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Diffstat (limited to 'sql/sql_base.cc')
| -rw-r--r-- | sql/sql_base.cc | 9239 |
1 files changed, 9239 insertions, 0 deletions
diff --git a/sql/sql_base.cc b/sql/sql_base.cc new file mode 100644 index 00000000..a9d7de9a --- /dev/null +++ b/sql/sql_base.cc @@ -0,0 +1,9239 @@ +/* Copyright (c) 2000, 2016, Oracle and/or its affiliates. + Copyright (c) 2010, 2021, MariaDB + + This program is free software; you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation; version 2 of the License. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */ + + +/* Basic functions needed by many modules */ + +#include "mariadb.h" +#include "sql_base.h" // setup_table_map +#include "sql_priv.h" +#include "unireg.h" +#include "debug_sync.h" +#include "lock.h" // mysql_lock_remove, + // mysql_unlock_tables, + // mysql_lock_have_duplicate +#include "sql_show.h" // append_identifier +#include "strfunc.h" // find_type +#include "sql_view.h" // mysql_make_view, VIEW_ANY_ACL +#include "sql_parse.h" // check_table_access +#include "sql_insert.h" // kill_delayed_threads +#include "sql_partition.h" // ALTER_PARTITION_PARAM_TYPE +#include "sql_derived.h" // mysql_derived_prepare, + // mysql_handle_derived, + // mysql_derived_filling +#include "sql_handler.h" // mysql_ha_flush +#include "sql_test.h" +#include "sql_partition.h" // ALTER_PARTITION_PARAM_TYPE +#include "log_event.h" // Query_log_event +#include "sql_select.h" +#include "sp_head.h" +#include "sp.h" +#include "sp_cache.h" +#include "sql_trigger.h" +#include "transaction.h" +#include "sql_prepare.h" +#include "sql_statistics.h" +#include "sql_cte.h" +#include <m_ctype.h> +#include <my_dir.h> +#include <hash.h> +#include "rpl_filter.h" +#include "sql_table.h" // build_table_filename +#include "datadict.h" // dd_frm_is_view() +#include "rpl_rli.h" // rpl_group_info +#ifdef __WIN__ +#include <io.h> +#endif +#include "wsrep_mysqld.h" +#ifdef WITH_WSREP +#include "wsrep_thd.h" +#include "wsrep_trans_observer.h" +#endif /* WITH_WSREP */ + + +bool +No_such_table_error_handler::handle_condition(THD *, + uint sql_errno, + const char*, + Sql_condition::enum_warning_level *level, + const char*, + Sql_condition ** cond_hdl) +{ + *cond_hdl= NULL; + if (sql_errno == ER_NO_SUCH_TABLE || sql_errno == ER_NO_SUCH_TABLE_IN_ENGINE) + { + m_handled_errors++; + return TRUE; + } + + if (*level == Sql_condition::WARN_LEVEL_ERROR) + m_unhandled_errors++; + return FALSE; +} + + +bool No_such_table_error_handler::safely_trapped_errors() +{ + /* + If m_unhandled_errors != 0, something else, unanticipated, happened, + so the error is not trapped but returned to the caller. + Multiple ER_NO_SUCH_TABLE can be raised in case of views. + */ + return ((m_handled_errors > 0) && (m_unhandled_errors == 0)); +} + + +/** + This internal handler is used to trap ER_NO_SUCH_TABLE and + ER_WRONG_MRG_TABLE errors during CHECK/REPAIR TABLE for MERGE + tables. +*/ + +class Repair_mrg_table_error_handler : public Internal_error_handler +{ +public: + Repair_mrg_table_error_handler() + : m_handled_errors(false), m_unhandled_errors(false) + {} + + bool handle_condition(THD *thd, + uint sql_errno, + const char* sqlstate, + Sql_condition::enum_warning_level *level, + const char* msg, + Sql_condition ** cond_hdl); + + /** + Returns TRUE if there were ER_NO_SUCH_/WRONG_MRG_TABLE and there + were no unhandled errors. FALSE otherwise. + */ + bool safely_trapped_errors() + { + /* + Check for m_handled_errors is here for extra safety. + It can be useful in situation when call to open_table() + fails because some error which was suppressed by another + error handler (e.g. in case of MDL deadlock which we + decided to solve by back-off and retry). + */ + return (m_handled_errors && (! m_unhandled_errors)); + } + +private: + bool m_handled_errors; + bool m_unhandled_errors; +}; + + +bool +Repair_mrg_table_error_handler::handle_condition(THD *, + uint sql_errno, + const char*, + Sql_condition::enum_warning_level *level, + const char*, + Sql_condition ** cond_hdl) +{ + *cond_hdl= NULL; + if (sql_errno == ER_NO_SUCH_TABLE || + sql_errno == ER_NO_SUCH_TABLE_IN_ENGINE || + sql_errno == ER_WRONG_MRG_TABLE) + { + m_handled_errors= true; + return TRUE; + } + + m_unhandled_errors= true; + return FALSE; +} + + +/** + @defgroup Data_Dictionary Data Dictionary + @{ +*/ + +static bool check_and_update_table_version(THD *thd, TABLE_LIST *tables, + TABLE_SHARE *table_share); +static bool open_table_entry_fini(THD *thd, TABLE_SHARE *share, TABLE *entry); +static bool auto_repair_table(THD *thd, TABLE_LIST *table_list); + + +/** + Get table cache key for a table list element. + + @param table_list[in] Table list element. + @param key[out] On return points to table cache key for the table. + + @note Unlike create_table_def_key() call this function doesn't construct + key in a buffer provided by caller. Instead it relies on the fact + that table list element for which key is requested has properly + initialized MDL_request object and the fact that table definition + cache key is suffix of key used in MDL subsystem. So to get table + definition key it simply needs to return pointer to appropriate + part of MDL_key object nested in this table list element. + Indeed, this means that lifetime of key produced by this call is + limited by the lifetime of table list element which it got as + parameter. + + @return Length of key. +*/ + +uint get_table_def_key(const TABLE_LIST *table_list, const char **key) +{ + /* + This call relies on the fact that TABLE_LIST::mdl_request::key object + is properly initialized, so table definition cache can be produced + from key used by MDL subsystem. + */ + DBUG_ASSERT(!strcmp(table_list->get_db_name(), + table_list->mdl_request.key.db_name())); + DBUG_ASSERT(!strcmp(table_list->get_table_name(), + table_list->mdl_request.key.name())); + + *key= (const char*)table_list->mdl_request.key.ptr() + 1; + return table_list->mdl_request.key.length() - 1; +} + + + +/***************************************************************************** + Functions to handle table definition cache (TABLE_SHARE) +*****************************************************************************/ + +/* + Create a list for all open tables matching SQL expression + + SYNOPSIS + list_open_tables() + thd Thread THD + wild SQL like expression + + NOTES + One gets only a list of tables for which one has any kind of privilege. + db and table names are allocated in result struct, so one doesn't need + a lock when traversing the return list. + + RETURN VALUES + NULL Error (Probably OOM) + # Pointer to list of names of open tables. +*/ + +struct list_open_tables_arg +{ + THD *thd; + const char *db; + const char *wild; + TABLE_LIST table_list; + OPEN_TABLE_LIST **start_list, *open_list; +}; + + +static my_bool list_open_tables_callback(TDC_element *element, + list_open_tables_arg *arg) +{ + const char *db= (char*) element->m_key; + size_t db_length= strlen(db); + const char *table_name= db + db_length + 1; + + if (arg->db && my_strcasecmp(system_charset_info, arg->db, db)) + return FALSE; + if (arg->wild && wild_compare(table_name, arg->wild, 0)) + return FALSE; + + /* Check if user has SELECT privilege for any column in the table */ + arg->table_list.db.str= db; + arg->table_list.db.length= db_length; + arg->table_list.table_name.str= table_name; + arg->table_list.table_name.length= strlen(table_name); + arg->table_list.grant.privilege= NO_ACL; + + if (check_table_access(arg->thd, SELECT_ACL, &arg->table_list, TRUE, 1, TRUE)) + return FALSE; + + if (!(*arg->start_list= (OPEN_TABLE_LIST *) arg->thd->alloc( + sizeof(**arg->start_list) + element->m_key_length))) + return TRUE; + + strmov((*arg->start_list)->table= + strmov(((*arg->start_list)->db= (char*) ((*arg->start_list) + 1)), + db) + 1, table_name); + (*arg->start_list)->in_use= 0; + + mysql_mutex_lock(&element->LOCK_table_share); + All_share_tables_list::Iterator it(element->all_tables); + TABLE *table; + while ((table= it++)) + if (table->in_use) + ++(*arg->start_list)->in_use; + mysql_mutex_unlock(&element->LOCK_table_share); + (*arg->start_list)->locked= 0; /* Obsolete. */ + arg->start_list= &(*arg->start_list)->next; + *arg->start_list= 0; + return FALSE; +} + + +OPEN_TABLE_LIST *list_open_tables(THD *thd, const char *db, const char *wild) +{ + list_open_tables_arg argument; + DBUG_ENTER("list_open_tables"); + + argument.thd= thd; + argument.db= db; + argument.wild= wild; + bzero((char*) &argument.table_list, sizeof(argument.table_list)); + argument.start_list= &argument.open_list; + argument.open_list= 0; + + if (tdc_iterate(thd, (my_hash_walk_action) list_open_tables_callback, + &argument, true)) + DBUG_RETURN(0); + + DBUG_RETURN(argument.open_list); +} + + +/** + Close all tables that are not in use in table definition cache +*/ + +void purge_tables() +{ + /* + Force close of all open tables. + + Note that code in TABLE_SHARE::wait_for_old_version() assumes that + incrementing of refresh_version is followed by purge of unused table + shares. + */ + kill_delayed_threads(); + /* + Get rid of all unused TABLE and TABLE_SHARE instances. By doing + this we automatically close all tables which were marked as "old". + */ + tc_purge(); + /* Free table shares which were not freed implicitly by loop above. */ + tdc_purge(true); +} + + +/** + close_cached_tables + + This function has two separate usages: + 1) Close not used tables in the table cache to free memory + 2) Close a list of tables and wait until they are not used anymore. This + is used mainly when preparing a table for export. + + If there are locked tables, they are closed and reopened before + function returns. This is done to ensure that table files will be closed + by all threads and thus external copyable when FLUSH TABLES returns. +*/ + +bool close_cached_tables(THD *thd, TABLE_LIST *tables, + bool wait_for_refresh, ulong timeout) +{ + DBUG_ENTER("close_cached_tables"); + DBUG_ASSERT(thd || (!wait_for_refresh && !tables)); + DBUG_ASSERT(wait_for_refresh || !tables); + + if (!tables) + { + /* Free tables that are not used */ + purge_tables(); + if (!wait_for_refresh) + DBUG_RETURN(false); + } + + DBUG_PRINT("info", ("open table definitions: %d", + (int) tdc_records())); + + if (thd->locked_tables_mode) + { + /* + If we are under LOCK TABLES, we need to reopen the tables without + opening a door for any concurrent threads to sneak in and get + lock on our tables. To achieve this we use exclusive metadata + locks. + */ + TABLE_LIST *tables_to_reopen= (tables ? tables : + thd->locked_tables_list.locked_tables()); + bool result= false; + + /* close open HANDLER for this thread to allow table to be closed */ + mysql_ha_flush_tables(thd, tables_to_reopen); + + for (TABLE_LIST *table_list= tables_to_reopen; table_list; + table_list= table_list->next_global) + { + int err; + /* A check that the table was locked for write is done by the caller. */ + TABLE *table= find_table_for_mdl_upgrade(thd, table_list->db.str, + table_list->table_name.str, &err); + + /* May return NULL if this table has already been closed via an alias. */ + if (! table) + continue; + + if (wait_while_table_is_used(thd, table, + HA_EXTRA_PREPARE_FOR_FORCED_CLOSE)) + { + result= true; + break; + } + close_all_tables_for_name(thd, table->s, HA_EXTRA_NOT_USED, NULL); + } + /* + No other thread has the locked tables open; reopen them and get the + old locks. This should always succeed (unless some external process + has removed the tables) + */ + if (thd->locked_tables_list.reopen_tables(thd, false)) + result= true; + + /* + Since downgrade_lock() won't do anything with shared + metadata lock it is much simpler to go through all open tables rather + than picking only those tables that were flushed. + */ + for (TABLE *tab= thd->open_tables; tab; tab= tab->next) + tab->mdl_ticket->downgrade_lock(MDL_SHARED_NO_READ_WRITE); + + DBUG_RETURN(result); + } + else if (tables) + { + /* + Get an explicit MDL lock for all requested tables to ensure they are + not used by any other thread + */ + MDL_request_list mdl_requests; + + DBUG_PRINT("info", ("Waiting for other threads to close their open tables")); + DEBUG_SYNC(thd, "after_flush_unlock"); + + /* close open HANDLER for this thread to allow table to be closed */ + mysql_ha_flush_tables(thd, tables); + + for (TABLE_LIST *table= tables; table; table= table->next_local) + { + MDL_request *mdl_request= new (thd->mem_root) MDL_request; + if (mdl_request == NULL) + DBUG_RETURN(true); + MDL_REQUEST_INIT_BY_KEY(mdl_request, &table->mdl_request.key, + MDL_EXCLUSIVE, MDL_STATEMENT); + mdl_requests.push_front(mdl_request); + } + + if (thd->mdl_context.acquire_locks(&mdl_requests, timeout)) + DBUG_RETURN(true); + + for (TABLE_LIST *table= tables; table; table= table->next_local) + tdc_remove_table(thd, table->db.str, table->table_name.str); + } + DBUG_RETURN(false); +} + + +/** + Collect all shares that has open tables +*/ + +struct tc_collect_arg +{ + DYNAMIC_ARRAY shares; + flush_tables_type flush_type; +}; + +static my_bool tc_collect_used_shares(TDC_element *element, + tc_collect_arg *arg) +{ + my_bool result= FALSE; + + DYNAMIC_ARRAY *shares= &arg->shares; + mysql_mutex_lock(&element->LOCK_table_share); + if (element->ref_count > 0 && !element->share->is_view) + { + DBUG_ASSERT(element->share); + bool do_flush= 0; + switch (arg->flush_type) { + case FLUSH_ALL: + do_flush= 1; + break; + case FLUSH_NON_TRANS_TABLES: + if (!element->share->online_backup && + element->share->table_category == TABLE_CATEGORY_USER) + do_flush= 1; + break; + case FLUSH_SYS_TABLES: + if (!element->share->online_backup && + element->share->table_category != TABLE_CATEGORY_USER) + do_flush= 1; + } + if (do_flush) + { + element->ref_count++; // Protect against delete + if (push_dynamic(shares, (uchar*) &element->share)) + result= TRUE; + } + } + mysql_mutex_unlock(&element->LOCK_table_share); + return result; +} + + +/* + Ignore errors from opening read only tables +*/ + +class flush_tables_error_handler : public Internal_error_handler +{ +public: + int handled_errors; + int unhandled_errors; + flush_tables_error_handler() : handled_errors(0), unhandled_errors(0) + {} + + bool handle_condition(THD *thd, + uint sql_errno, + const char* sqlstate, + Sql_condition::enum_warning_level *level, + const char* msg, + Sql_condition ** cond_hdl) + { + *cond_hdl= NULL; + if (sql_errno == ER_OPEN_AS_READONLY) + { + handled_errors++; + return TRUE; + } + if (*level == Sql_condition::WARN_LEVEL_ERROR) + unhandled_errors++; + return FALSE; + } + + bool got_fatal_error() + { + return unhandled_errors > 0; + } +}; + + +/** + Flush cached table as part of global read lock + + @param thd + @param flag What type of tables should be flushed + + @return 0 ok + @return 1 error + + After we get the list of table shares, we will call flush on all + possible tables, even if some flush fails. +*/ + +bool flush_tables(THD *thd, flush_tables_type flag) +{ + bool result= TRUE; + tc_collect_arg collect_arg; + TABLE *tmp_table; + flush_tables_error_handler error_handler; + DBUG_ENTER("flush_tables"); + + purge_tables(); /* Flush unused tables and shares */ + + /* + Loop over all shares and collect shares that have open tables + TODO: + Optimize this to only collect shares that have been used for + write after last time all tables was closed. + */ + + if (!(tmp_table= (TABLE*) my_malloc(PSI_INSTRUMENT_ME, sizeof(*tmp_table), + MYF(MY_WME | MY_THREAD_SPECIFIC)))) + DBUG_RETURN(1); + + my_init_dynamic_array(PSI_INSTRUMENT_ME, &collect_arg.shares, + sizeof(TABLE_SHARE*), 100, 100, MYF(0)); + collect_arg.flush_type= flag; + if (tdc_iterate(thd, (my_hash_walk_action) tc_collect_used_shares, + &collect_arg, true)) + { + /* Release already collected shares */ + for (uint i= 0 ; i < collect_arg.shares.elements ; i++) + { + TABLE_SHARE *share= *dynamic_element(&collect_arg.shares, i, + TABLE_SHARE**); + tdc_release_share(share); + } + goto err; + } + + /* Call HA_EXTRA_FLUSH on all found shares */ + + thd->push_internal_handler(&error_handler); + for (uint i= 0 ; i < collect_arg.shares.elements ; i++) + { + TABLE_SHARE *share= *dynamic_element(&collect_arg.shares, i, + TABLE_SHARE**); + TABLE *table= tc_acquire_table(thd, share->tdc); + if (table) + { + (void) table->file->extra(HA_EXTRA_FLUSH); + tc_release_table(table); + } + else + { + /* + HA_OPEN_FOR_FLUSH is used to allow us to open the table even if + TABLE_SHARE::incompatible_version is set. It also will tell + SEQUENCE engine that we don't have to read the sequence information + (which may cause deadlocks with concurrently running ALTER TABLE or + ALTER SEQUENCE) as we will close the table at once. + */ + if (!open_table_from_share(thd, share, &empty_clex_str, + HA_OPEN_KEYFILE, 0, + HA_OPEN_FOR_ALTER | HA_OPEN_FOR_FLUSH, + tmp_table, FALSE, + NULL)) + { + (void) tmp_table->file->extra(HA_EXTRA_FLUSH); + /* + We don't put the table into the TDC as the table was not fully + opened (we didn't open triggers) + */ + closefrm(tmp_table); + } + } + tdc_release_share(share); + } + thd->pop_internal_handler(); + result= error_handler.got_fatal_error(); + DBUG_PRINT("note", ("open_errors: %u %u", + error_handler.handled_errors, + error_handler.unhandled_errors)); +err: + my_free(tmp_table); + delete_dynamic(&collect_arg.shares); + DBUG_RETURN(result); +} + + +/* + Mark all tables in the list which were used by current substatement + as free for reuse. + + SYNOPSIS + mark_used_tables_as_free_for_reuse() + thd - thread context + table - head of the list of tables + + DESCRIPTION + Marks all tables in the list which were used by current substatement + (they are marked by its query_id) as free for reuse. + + Clear 'check_table_binlog_row_based_done' flag. For tables which were used + by current substatement the flag is cleared as part of 'ha_reset()' call. + For the rest of the open tables not used by current substament if this + flag is enabled as part of current substatement execution, + (for example when THD::binlog_write_table_maps() calls + prepare_for_row_logging()), clear the flag explicitly. + + NOTE + The reason we reset query_id is that it's not enough to just test + if table->query_id != thd->query_id to know if a table is in use. + + For example + SELECT f1_that_uses_t1() FROM t1; + In f1_that_uses_t1() we will see one instance of t1 where query_id is + set to query_id of original query. +*/ + +static void mark_used_tables_as_free_for_reuse(THD *thd, TABLE *table) +{ + DBUG_ENTER("mark_used_tables_as_free_for_reuse"); + for (; table ; table= table->next) + { + DBUG_ASSERT(table->pos_in_locked_tables == NULL || + table->pos_in_locked_tables->table == table); + if (table->query_id == thd->query_id) + { + table->query_id= 0; + table->file->ha_reset(); + } + else + table->file->clear_cached_table_binlog_row_based_flag(); + } + DBUG_VOID_RETURN; +} + + +/** + Close all open instances of the table but keep the MDL lock. + + Works both under LOCK TABLES and in the normal mode. + Removes all closed instances of the table from the table cache. + + @param thd thread handle + @param[in] share table share, but is just a handy way to + access the table cache key + + @param[in] extra + HA_EXTRA_PREPARE_FOR_DROP + - The table is dropped + HA_EXTRA_PREPARE_FOR_RENAME + - The table is renamed + HA_EXTRA_NOT_USED + - The table is marked as closed in the + locked_table_list but kept there so one can call + locked_table_list->reopen_tables() to put it back. + + In case of drop/rename the documented behavior is to + implicitly remove the table from LOCK TABLES + list. + + @pre Must be called with an X MDL lock on the table. +*/ + +void +close_all_tables_for_name(THD *thd, TABLE_SHARE *share, + ha_extra_function extra, + TABLE *skip_table) +{ + DBUG_ASSERT(!share->tmp_table); + DBUG_ASSERT(share->tdc->flushed); + + char key[MAX_DBKEY_LENGTH]; + size_t key_length= share->table_cache_key.length; + bool remove_from_locked_tables= extra != HA_EXTRA_NOT_USED; + + memcpy(key, share->table_cache_key.str, key_length); + + for (TABLE **prev= &thd->open_tables; *prev; ) + { + TABLE *table= *prev; + + if (table->s->table_cache_key.length == key_length && + !memcmp(table->s->table_cache_key.str, key, key_length) && + table != skip_table) + { + thd->locked_tables_list.unlink_from_list(thd, + table->pos_in_locked_tables, + remove_from_locked_tables); + /* Inform handler that there is a drop table or a rename going on */ + if (extra != HA_EXTRA_NOT_USED && table->db_stat) + { + table->file->extra(extra); + extra= HA_EXTRA_NOT_USED; // Call extra once! + } + + /* + Does nothing if the table is not locked. + This allows one to use this function after a table + has been unlocked, e.g. in partition management. + */ + mysql_lock_remove(thd, thd->lock, table); + close_thread_table(thd, prev); + } + else + { + /* Step to next entry in open_tables list. */ + prev= &table->next; + } + } +} + + +/* + Close all tables used by the current substatement, or all tables + used by this thread if we are on the upper level. + + SYNOPSIS + close_thread_tables() + thd Thread handler + + IMPLEMENTATION + Unlocks tables and frees derived tables. + Put all normal tables used by thread in free list. + + It will only close/mark as free for reuse tables opened by this + substatement, it will also check if we are closing tables after + execution of complete query (i.e. we are on upper level) and will + leave prelocked mode if needed. +*/ + +int close_thread_tables(THD *thd) +{ + TABLE *table; + int error= 0; + DBUG_ENTER("close_thread_tables"); + + THD_STAGE_INFO(thd, stage_closing_tables); + +#ifdef EXTRA_DEBUG + DBUG_PRINT("tcache", ("open tables:")); + for (table= thd->open_tables; table; table= table->next) + DBUG_PRINT("tcache", ("table: '%s'.'%s' %p", table->s->db.str, + table->s->table_name.str, table)); +#endif + +#if defined(ENABLED_DEBUG_SYNC) + /* debug_sync may not be initialized for some slave threads */ + if (thd->debug_sync_control) + DEBUG_SYNC(thd, "before_close_thread_tables"); +#endif + + DBUG_ASSERT(thd->transaction->stmt.is_empty() || thd->in_sub_stmt || + (thd->state_flags & Open_tables_state::BACKUPS_AVAIL)); + + for (table= thd->open_tables; table; table= table->next) + { + /* Table might be in use by some outer statement. */ + DBUG_PRINT("tcache", ("table: '%s' query_id: %lu", + table->s->table_name.str, (ulong) table->query_id)); + + /* Detach MERGE children after every statement. Even under LOCK TABLES. */ + if (thd->locked_tables_mode <= LTM_LOCK_TABLES || + table->query_id == thd->query_id) + { + DBUG_ASSERT(table->file); + table->file->extra(HA_EXTRA_DETACH_CHILDREN); + } + } + + /* + We are assuming here that thd->derived_tables contains ONLY derived + tables for this substatement. i.e. instead of approach which uses + query_id matching for determining which of the derived tables belong + to this substatement we rely on the ability of substatements to + save/restore thd->derived_tables during their execution. + + TODO: Probably even better approach is to simply associate list of + derived tables with (sub-)statement instead of thread and destroy + them at the end of its execution. + */ + if (thd->derived_tables) + { + TABLE *next; + /* + Close all derived tables generated in queries like + SELECT * FROM (SELECT * FROM t1) + */ + for (table= thd->derived_tables ; table ; table= next) + { + next= table->next; + free_tmp_table(thd, table); + } + thd->derived_tables= 0; + } + + if (thd->rec_tables) + { + TABLE *next; + /* + Close all temporary tables created for recursive table references. + This action was postponed because the table could be used in the + statements like ANALYZE WITH r AS (...) SELECT * from r + where r is defined through recursion. + */ + for (table= thd->rec_tables ; table ; table= next) + { + next= table->next; + free_tmp_table(thd, table); + } + thd->rec_tables= 0; + } + + /* + Mark all temporary tables used by this statement as free for reuse. + */ + thd->mark_tmp_tables_as_free_for_reuse(); + + if (thd->locked_tables_mode) + { + + /* Ensure we are calling ha_reset() for all used tables */ + mark_used_tables_as_free_for_reuse(thd, thd->open_tables); + + /* + We are under simple LOCK TABLES or we're inside a sub-statement + of a prelocked statement, so should not do anything else. + + Note that even if we are in LTM_LOCK_TABLES mode and statement + requires prelocking (e.g. when we are closing tables after + failing ot "open" all tables required for statement execution) + we will exit this function a few lines below. + */ + if (! thd->lex->requires_prelocking()) + DBUG_RETURN(0); + + /* + We are in the top-level statement of a prelocked statement, + so we have to leave the prelocked mode now with doing implicit + UNLOCK TABLES if needed. + */ + if (thd->locked_tables_mode == LTM_PRELOCKED_UNDER_LOCK_TABLES) + thd->locked_tables_mode= LTM_LOCK_TABLES; + + if (thd->locked_tables_mode == LTM_LOCK_TABLES) + DBUG_RETURN(0); + + thd->leave_locked_tables_mode(); + + /* Fallthrough */ + } + + if (thd->lock) + { + /* + For RBR we flush the pending event just before we unlock all the + tables. This means that we are at the end of a topmost + statement, so we ensure that the STMT_END_F flag is set on the + pending event. For statements that are *inside* stored + functions, the pending event will not be flushed: that will be + handled either before writing a query log event (inside + binlog_query()) or when preparing a pending event. + */ + (void)thd->binlog_flush_pending_rows_event(TRUE); + error= mysql_unlock_tables(thd, thd->lock); + thd->lock=0; + } + /* + Closing a MERGE child before the parent would be fatal if the + other thread tries to abort the MERGE lock in between. + */ + while (thd->open_tables) + (void) close_thread_table(thd, &thd->open_tables); + + DBUG_RETURN(error); +} + + +/* move one table to free list */ + +void close_thread_table(THD *thd, TABLE **table_ptr) +{ + TABLE *table= *table_ptr; + DBUG_ENTER("close_thread_table"); + DBUG_PRINT("tcache", ("table: '%s'.'%s' %p", table->s->db.str, + table->s->table_name.str, table)); + DBUG_ASSERT(!table->file->keyread_enabled()); + DBUG_ASSERT(!table->file || table->file->inited == handler::NONE); + + /* + The metadata lock must be released after giving back + the table to the table cache. + */ + DBUG_ASSERT(thd->mdl_context.is_lock_owner(MDL_key::TABLE, + table->s->db.str, + table->s->table_name.str, + MDL_SHARED)); + table->mdl_ticket= NULL; + + if (table->file) + { + table->file->update_global_table_stats(); + table->file->update_global_index_stats(); + } + + /* + This look is needed to allow THD::notify_shared_lock() to + traverse the thd->open_tables list without having to worry that + some of the tables are removed from under it + */ + + mysql_mutex_lock(&thd->LOCK_thd_data); + *table_ptr=table->next; + mysql_mutex_unlock(&thd->LOCK_thd_data); + + if (! table->needs_reopen()) + { + /* Avoid having MERGE tables with attached children in table cache. */ + table->file->extra(HA_EXTRA_DETACH_CHILDREN); + /* Free memory and reset for next loop. */ + free_field_buffers_larger_than(table, MAX_TDC_BLOB_SIZE); + table->file->ha_reset(); + } + + /* + Do this *before* entering the TABLE_SHARE::tdc.LOCK_table_share + critical section. + */ + MYSQL_UNBIND_TABLE(table->file); + + tc_release_table(table); + DBUG_VOID_RETURN; +} + + +/* + Find table in list. + + SYNOPSIS + find_table_in_list() + table Pointer to table list + offset Offset to which list in table structure to use + db_name Data base name + table_name Table name + + NOTES: + This is called by find_table_in_global_list(). + + RETURN VALUES + NULL Table not found + # Pointer to found table. +*/ + +TABLE_LIST *find_table_in_list(TABLE_LIST *table, + TABLE_LIST *TABLE_LIST::*link, + const LEX_CSTRING *db_name, + const LEX_CSTRING *table_name) +{ + for (; table; table= table->*link ) + { + if (cmp(&table->db, db_name) == 0 && + cmp(&table->table_name, table_name) == 0) + break; + } + return table; +} + + +/** + Test that table is unique (It's only exists once in the table list) + + @param thd thread handle + @param table table which should be checked + @param table_list list of tables + @param check_flag whether to check tables' aliases + Currently this is only used by INSERT + + NOTE: to exclude derived tables from check we use following mechanism: + a) during derived table processing set THD::derived_tables_processing + b) JOIN::prepare set SELECT::exclude_from_table_unique_test if + THD::derived_tables_processing set. (we can't use JOIN::execute + because for PS we perform only JOIN::prepare, but we can't set this + flag in JOIN::prepare if we are not sure that we are in derived table + processing loop, because multi-update call fix_fields() for some its + items (which mean JOIN::prepare for subqueries) before unique_table + call to detect which tables should be locked for write). + c) find_dup_table skip all tables which belong to SELECT with + SELECT::exclude_from_table_unique_test set. + Also SELECT::exclude_from_table_unique_test used to exclude from check + tables of main SELECT of multi-delete and multi-update + + We also skip tables with TABLE_LIST::prelocking_placeholder set, + because we want to allow SELECTs from them, and their modification + will rise the error anyway. + + TODO: when we will have table/view change detection we can do this check + only once for PS/SP + + @retval !=0 found duplicate + @retval 0 if table is unique +*/ + +static +TABLE_LIST* find_dup_table(THD *thd, TABLE_LIST *table, TABLE_LIST *table_list, + uint check_flag) +{ + TABLE_LIST *res= 0; + LEX_CSTRING *d_name, *t_name, *t_alias; + DBUG_ENTER("find_dup_table"); + DBUG_PRINT("enter", ("table alias: %s", table->alias.str)); + + /* + If this function called for query which update table (INSERT/UPDATE/...) + then we have in table->table pointer to TABLE object which we are + updating even if it is VIEW so we need TABLE_LIST of this TABLE object + to get right names (even if lower_case_table_names used). + + If this function called for CREATE command that we have not opened table + (table->table equal to 0) and right names is in current TABLE_LIST + object. + */ + if (table->table) + { + /* All MyISAMMRG children are plain MyISAM tables. */ + DBUG_ASSERT(table->table->file->ht->db_type != DB_TYPE_MRG_MYISAM); + + table= table->find_underlying_table(table->table); + /* + as far as we have table->table we have to find real TABLE_LIST of + it in underlying tables + */ + DBUG_ASSERT(table); + } + d_name= &table->db; + t_name= &table->table_name; + t_alias= &table->alias; + +retry: + DBUG_PRINT("info", ("real table: %s.%s", d_name->str, t_name->str)); + for (TABLE_LIST *tl= table_list; tl ; tl= tl->next_global, res= 0) + { + if (tl->select_lex && tl->select_lex->master_unit() && + tl->select_lex->master_unit()->executed) + { + /* + There is no sense to check tables of already executed parts + of the query + */ + continue; + } + /* + Table is unique if it is present only once in the global list + of tables and once in the list of table locks. + */ + if (! (res= find_table_in_global_list(tl, d_name, t_name))) + break; + tl= res; // We can continue search after this table + + /* Skip if same underlying table. */ + if (res->table && (res->table == table->table)) + continue; + + /* Skip if table is tmp table */ + if (check_flag & CHECK_DUP_SKIP_TEMP_TABLE && + res->table && res->table->s->tmp_table != NO_TMP_TABLE) + { + continue; + } + if (check_flag & CHECK_DUP_FOR_CREATE) + DBUG_RETURN(res); + + /* Skip if table alias does not match. */ + if (check_flag & CHECK_DUP_ALLOW_DIFFERENT_ALIAS) + { + if (my_strcasecmp(table_alias_charset, t_alias->str, res->alias.str)) + continue; + } + + /* + If table is not excluded (could be a derived table) and table is not + a prelocking placeholder then we found either a duplicate entry + or a table that is part of a derived table (handled below). + Examples are: + INSERT INTO t1 SELECT * FROM t1; + INSERT INTO t1 SELECT * FROM view_containing_t1; + */ + if (res->select_lex && + !res->select_lex->exclude_from_table_unique_test && + !res->prelocking_placeholder) + break; + + /* + If we found entry of this table or table of SELECT which already + processed in derived table or top select of multi-update/multi-delete + (exclude_from_table_unique_test) or prelocking placeholder. + */ + DBUG_PRINT("info", + ("found same copy of table or table which we should skip")); + } + if (res && res->belong_to_derived) + { + /* + We come here for queries of type: + INSERT INTO t1 (SELECT tmp.a FROM (select * FROM t1) as tmp); + + Try to fix by materializing the derived table + */ + TABLE_LIST *derived= res->belong_to_derived; + if (derived->is_merged_derived() && !derived->derived->is_excluded()) + { + DBUG_PRINT("info", + ("convert merged to materialization to resolve the conflict")); + derived->change_refs_to_fields(); + derived->set_materialized_derived(); + goto retry; + } + } + DBUG_RETURN(res); +} + + +/** + Test that the subject table of INSERT/UPDATE/DELETE/CREATE + or (in case of MyISAMMRG) one of its children are not used later + in the query. + + For MyISAMMRG tables, it is assumed that all the underlying + tables of @c table (if any) are listed right after it and that + their @c parent_l field points at the main table. + + + @retval non-NULL The table list element for the table that + represents the duplicate. + @retval NULL No duplicates found. +*/ + +TABLE_LIST* +unique_table(THD *thd, TABLE_LIST *table, TABLE_LIST *table_list, + uint check_flag) +{ + TABLE_LIST *dup; + + table= table->find_table_for_update(); + + if (table->table && + table->table->file->ha_table_flags() & HA_CAN_MULTISTEP_MERGE) + { + TABLE_LIST *child; + dup= NULL; + /* Check duplicates of all merge children. */ + for (child= table->next_global; child; + child= child->next_global) + { + if (child->table && + child->table->file->ha_table_flags() & HA_CAN_MULTISTEP_MERGE) + continue; + + /* + Ensure that the child has one parent that is the table that is + updated. + */ + TABLE_LIST *tmp_parent= child; + while ((tmp_parent= tmp_parent->parent_l)) + { + if (tmp_parent == table) + break; + } + if (!tmp_parent) + break; + + if ((dup= find_dup_table(thd, child, child->next_global, check_flag))) + break; + } + } + else + dup= find_dup_table(thd, table, table_list, check_flag); + return dup; +} + + +/* + Issue correct error message in case we found 2 duplicate tables which + prevent some update operation + + SYNOPSIS + update_non_unique_table_error() + update table which we try to update + operation name of update operation + duplicate duplicate table which we found + + NOTE: + here we hide view underlying tables if we have them +*/ + +void update_non_unique_table_error(TABLE_LIST *update, + const char *operation, + TABLE_LIST *duplicate) +{ + update= update->top_table(); + duplicate= duplicate->top_table(); + if (!update->view || !duplicate->view || + update->view == duplicate->view || + update->view_name.length != duplicate->view_name.length || + update->view_db.length != duplicate->view_db.length || + lex_string_cmp(table_alias_charset, + &update->view_name, &duplicate->view_name) != 0 || + lex_string_cmp(table_alias_charset, + &update->view_db, &duplicate->view_db) != 0) + { + /* + it is not the same view repeated (but it can be parts of the same copy + of view), so we have to hide underlying tables. + */ + if (update->view) + { + /* Issue the ER_NON_INSERTABLE_TABLE error for an INSERT */ + if (update->view == duplicate->view) + my_error(!strncmp(operation, "INSERT", 6) ? + ER_NON_INSERTABLE_TABLE : ER_NON_UPDATABLE_TABLE, MYF(0), + update->alias.str, operation); + else + my_error(ER_VIEW_PREVENT_UPDATE, MYF(0), + (duplicate->view ? duplicate->alias.str : update->alias.str), + operation, update->alias.str); + return; + } + if (duplicate->view) + { + my_error(ER_VIEW_PREVENT_UPDATE, MYF(0), duplicate->alias.str, operation, + update->alias.str); + return; + } + } + my_error(ER_UPDATE_TABLE_USED, MYF(0), update->alias.str, operation); +} + + +/** + Force all other threads to stop using the table by upgrading + metadata lock on it and remove unused TABLE instances from cache. + + @param thd Thread handler + @param table Table to remove from cache + @param function HA_EXTRA_PREPARE_FOR_DROP if table is to be deleted + HA_EXTRA_FORCE_REOPEN if table is not be used + HA_EXTRA_PREPARE_FOR_RENAME if table is to be renamed + HA_EXTRA_NOT_USED Don't call extra() + + @note When returning, the table will be unusable for other threads + until metadata lock is downgraded. + + @retval FALSE Success. + @retval TRUE Failure (e.g. because thread was killed). +*/ + +bool wait_while_table_is_used(THD *thd, TABLE *table, + enum ha_extra_function function) +{ + DBUG_ENTER("wait_while_table_is_used"); + DBUG_ASSERT(!table->s->tmp_table); + DBUG_PRINT("enter", ("table: '%s' share: %p db_stat: %u", + table->s->table_name.str, table->s, + table->db_stat)); + + if (thd->mdl_context.upgrade_shared_lock( + table->mdl_ticket, MDL_EXCLUSIVE, + thd->variables.lock_wait_timeout)) + DBUG_RETURN(TRUE); + + table->s->tdc->flush(thd, true); + /* extra() call must come only after all instances above are closed */ + if (function != HA_EXTRA_NOT_USED) + { + int error= table->file->extra(function); + if (error) + table->file->print_error(error, MYF(0)); + DBUG_RETURN(error); + } + DBUG_RETURN(FALSE); +} + + +/** + Close a and drop a just created table in CREATE TABLE ... SELECT. + + @param thd Thread handle + @param table TABLE object for the table to be dropped + @param db_name Name of database for this table + @param table_name Name of this table + + This routine assumes that the table to be closed is open only + by the calling thread, so we needn't wait until other threads + close the table. It also assumes that the table is first + in thd->open_ables and a data lock on it, if any, has been + released. To sum up, it's tuned to work with + CREATE TABLE ... SELECT and CREATE TABLE .. SELECT only. + Note, that currently CREATE TABLE ... SELECT is not supported + under LOCK TABLES. This function, still, can be called in + prelocked mode, e.g. if we do CREATE TABLE .. SELECT f1(); +*/ + +void drop_open_table(THD *thd, TABLE *table, const LEX_CSTRING *db_name, + const LEX_CSTRING *table_name) +{ + DBUG_ENTER("drop_open_table"); + if (table->s->tmp_table) + thd->drop_temporary_table(table, NULL, true); + else + { + DBUG_ASSERT(table == thd->open_tables); + + handlerton *table_type= table->s->db_type(); + table->file->extra(HA_EXTRA_PREPARE_FOR_DROP); + table->s->tdc->flush(thd, true); + close_thread_table(thd, &thd->open_tables); + /* Remove the table from the storage engine and rm the .frm. */ + quick_rm_table(thd, table_type, db_name, table_name, 0); + } + DBUG_VOID_RETURN; +} + + +/** + An error handler which converts, if possible, ER_LOCK_DEADLOCK error + that can occur when we are trying to acquire a metadata lock to + a request for back-off and re-start of open_tables() process. +*/ + +class MDL_deadlock_handler : public Internal_error_handler +{ +public: + MDL_deadlock_handler(Open_table_context *ot_ctx_arg) + : m_ot_ctx(ot_ctx_arg), m_is_active(FALSE) + {} + + virtual ~MDL_deadlock_handler() {} + + virtual bool handle_condition(THD *thd, + uint sql_errno, + const char* sqlstate, + Sql_condition::enum_warning_level *level, + const char* msg, + Sql_condition ** cond_hdl); + +private: + /** Open table context to be used for back-off request. */ + Open_table_context *m_ot_ctx; + /** + Indicates that we are already in the process of handling + ER_LOCK_DEADLOCK error. Allows to re-emit the error from + the error handler without falling into infinite recursion. + */ + bool m_is_active; +}; + + +bool MDL_deadlock_handler::handle_condition(THD *, + uint sql_errno, + const char*, + Sql_condition::enum_warning_level*, + const char*, + Sql_condition ** cond_hdl) +{ + *cond_hdl= NULL; + if (! m_is_active && sql_errno == ER_LOCK_DEADLOCK) + { + /* Disable the handler to avoid infinite recursion. */ + m_is_active= TRUE; + (void) m_ot_ctx->request_backoff_action( + Open_table_context::OT_BACKOFF_AND_RETRY, + NULL); + m_is_active= FALSE; + /* + If the above back-off request failed, a new instance of + ER_LOCK_DEADLOCK error was emitted. Thus the current + instance of error condition can be treated as handled. + */ + return TRUE; + } + return FALSE; +} + + +/** + Try to acquire an MDL lock for a table being opened. + + @param[in,out] thd Session context, to report errors. + @param[out] ot_ctx Open table context, to hold the back off + state. If we failed to acquire a lock + due to a lock conflict, we add the + failed request to the open table context. + @param[in,out] mdl_request A request for an MDL lock. + If we managed to acquire a ticket + (no errors or lock conflicts occurred), + contains a reference to it on + return. However, is not modified if MDL + lock type- modifying flags were provided. + @param[in] flags flags MYSQL_OPEN_FORCE_SHARED_MDL, + MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL or + MYSQL_OPEN_FAIL_ON_MDL_CONFLICT + @sa open_table(). + @param[out] mdl_ticket Only modified if there was no error. + If we managed to acquire an MDL + lock, contains a reference to the + ticket, otherwise is set to NULL. + + @retval TRUE An error occurred. + @retval FALSE No error, but perhaps a lock conflict, check mdl_ticket. +*/ + +static bool +open_table_get_mdl_lock(THD *thd, Open_table_context *ot_ctx, + MDL_request *mdl_request, + uint flags, + MDL_ticket **mdl_ticket) +{ + MDL_request mdl_request_shared; + + if (flags & (MYSQL_OPEN_FORCE_SHARED_MDL | + MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL)) + { + /* + MYSQL_OPEN_FORCE_SHARED_MDL flag means that we are executing + PREPARE for a prepared statement and want to override + the type-of-operation aware metadata lock which was set + in the parser/during view opening with a simple shared + metadata lock. + This is necessary to allow concurrent execution of PREPARE + and LOCK TABLES WRITE statement against the same table. + + MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL flag means that we open + the table in order to get information about it for one of I_S + queries and also want to override the type-of-operation aware + shared metadata lock which was set earlier (e.g. during view + opening) with a high-priority shared metadata lock. + This is necessary to avoid unnecessary waiting and extra + ER_WARN_I_S_SKIPPED_TABLE warnings when accessing I_S tables. + + These two flags are mutually exclusive. + */ + DBUG_ASSERT(!(flags & MYSQL_OPEN_FORCE_SHARED_MDL) || + !(flags & MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL)); + + MDL_REQUEST_INIT_BY_KEY(&mdl_request_shared, &mdl_request->key, + flags & MYSQL_OPEN_FORCE_SHARED_MDL ? MDL_SHARED : MDL_SHARED_HIGH_PRIO, + MDL_TRANSACTION); + mdl_request= &mdl_request_shared; + } + + if (flags & MYSQL_OPEN_FAIL_ON_MDL_CONFLICT) + { + /* + When table is being open in order to get data for I_S table, + we might have some tables not only open but also locked (e.g. when + this happens under LOCK TABLES or in a stored function). + As a result by waiting on a conflicting metadata lock to go away + we may create a deadlock which won't entirely belong to the + MDL subsystem and thus won't be detectable by this subsystem's + deadlock detector. + To avoid such situation we skip the trouble-making table if + there is a conflicting lock. + */ + if (thd->mdl_context.try_acquire_lock(mdl_request)) + return TRUE; + if (mdl_request->ticket == NULL) + { + my_error(ER_WARN_I_S_SKIPPED_TABLE, MYF(0), + mdl_request->key.db_name(), mdl_request->key.name()); + return TRUE; + } + } + else + { + /* + We are doing a normal table open. Let us try to acquire a metadata + lock on the table. If there is a conflicting lock, acquire_lock() + will wait for it to go away. Sometimes this waiting may lead to a + deadlock, with the following results: + 1) If a deadlock is entirely within MDL subsystem, it is + detected by the deadlock detector of this subsystem. + ER_LOCK_DEADLOCK error is produced. Then, the error handler + that is installed prior to the call to acquire_lock() attempts + to request a back-off and retry. Upon success, ER_LOCK_DEADLOCK + error is suppressed, otherwise propagated up the calling stack. + 2) Otherwise, a deadlock may occur when the wait-for graph + includes edges not visible to the MDL deadlock detector. + One such example is a wait on an InnoDB row lock, e.g. when: + conn C1 gets SR MDL lock on t1 with SELECT * FROM t1 + conn C2 gets a row lock on t2 with SELECT * FROM t2 FOR UPDATE + conn C3 gets in and waits on C1 with DROP TABLE t0, t1 + conn C2 continues and blocks on C3 with SELECT * FROM t0 + conn C1 deadlocks by waiting on C2 by issuing SELECT * FROM + t2 LOCK IN SHARE MODE. + Such circular waits are currently only resolved by timeouts, + e.g. @@innodb_lock_wait_timeout or @@lock_wait_timeout. + */ + MDL_deadlock_handler mdl_deadlock_handler(ot_ctx); + + thd->push_internal_handler(&mdl_deadlock_handler); + bool result= thd->mdl_context.acquire_lock(mdl_request, + ot_ctx->get_timeout()); + thd->pop_internal_handler(); + + if (result && !ot_ctx->can_recover_from_failed_open()) + return TRUE; + } + *mdl_ticket= mdl_request->ticket; + return FALSE; +} + +#ifdef WITH_PARTITION_STORAGE_ENGINE +/* Set all [named] partitions as used. */ +static int set_partitions_as_used(TABLE_LIST *tl, TABLE *t) +{ + if (t->part_info) + return t->file->change_partitions_to_open(tl->partition_names); + return 0; +} +#endif + + +/** + Check if the given table is actually a VIEW that was LOCK-ed + + @param thd Thread context. + @param t Table to check. + + @retval TRUE The 't'-table is a locked view + needed to remedy problem before retrying again. + @retval FALSE 't' was not locked, not a VIEW or an error happened. +*/ + +bool is_locked_view(THD *thd, TABLE_LIST *t) +{ + DBUG_ENTER("is_locked_view"); + /* + Is this table a view and not a base table? + (it is work around to allow to open view with locked tables, + real fix will be made after definition cache will be made) + + Since opening of view which was not explicitly locked by LOCK + TABLES breaks metadata locking protocol (potentially can lead + to deadlocks) it should be disallowed. + */ + if (thd->mdl_context.is_lock_owner(MDL_key::TABLE, t->db.str, + t->table_name.str, MDL_SHARED)) + { + char path[FN_REFLEN + 1]; + build_table_filename(path, sizeof(path) - 1, + t->db.str, t->table_name.str, reg_ext, 0); + /* + Note that we can't be 100% sure that it is a view since it's + possible that we either simply have not found unused TABLE + instance in THD::open_tables list or were unable to open table + during prelocking process (in this case in theory we still + should hold shared metadata lock on it). + */ + if (dd_frm_is_view(thd, path)) + { + /* + If parent_l of the table_list is non null then a merge table + has this view as child table, which is not supported. + */ + if (t->parent_l) + { + my_error(ER_WRONG_MRG_TABLE, MYF(0)); + DBUG_RETURN(FALSE); + } + + if (!tdc_open_view(thd, t, CHECK_METADATA_VERSION)) + { + DBUG_ASSERT(t->view != 0); + DBUG_RETURN(TRUE); // VIEW + } + } + } + + DBUG_RETURN(FALSE); +} + + +/** + Open a base table. + + @param thd Thread context. + @param table_list Open first table in list. + @param ot_ctx Context with flags which modify how open works + and which is used to recover from a failed + open_table() attempt. + Some examples of flags: + MYSQL_OPEN_IGNORE_FLUSH - Open table even if + someone has done a flush. No version number + checking is done. + MYSQL_OPEN_HAS_MDL_LOCK - instead of acquiring + metadata locks rely on that caller already has + appropriate ones. + + Uses a cache of open tables to find a TABLE instance not in use. + + If TABLE_LIST::open_strategy is set to OPEN_IF_EXISTS, the table is + opened only if it exists. If the open strategy is OPEN_STUB, the + underlying table is never opened. In both cases, metadata locks are + always taken according to the lock strategy. + + The function used to open temporary tables, but now it opens base tables + only. + + @retval TRUE Open failed. "action" parameter may contain type of action + needed to remedy problem before retrying again. + @retval FALSE Success. Members of TABLE_LIST structure are filled properly + (e.g. TABLE_LIST::table is set for real tables and + TABLE_LIST::view is set for views). +*/ + +bool open_table(THD *thd, TABLE_LIST *table_list, Open_table_context *ot_ctx) +{ + TABLE *table; + const char *key; + uint key_length; + const char *alias= table_list->alias.str; + uint flags= ot_ctx->get_flags(); + MDL_ticket *mdl_ticket; + TABLE_SHARE *share; + uint gts_flags; +#ifdef WITH_PARTITION_STORAGE_ENGINE + int part_names_error=0; +#endif + DBUG_ENTER("open_table"); + + /* + The table must not be opened already. The table can be pre-opened for + some statements if it is a temporary table. + + open_temporary_table() must be used to open temporary tables. + */ + DBUG_ASSERT(!table_list->table); + + /* an open table operation needs a lot of the stack space */ + if (check_stack_overrun(thd, STACK_MIN_SIZE_FOR_OPEN, (uchar *)&alias)) + DBUG_RETURN(TRUE); + + if (!(flags & MYSQL_OPEN_IGNORE_KILLED) && thd->killed) + { + thd->send_kill_message(); + DBUG_RETURN(TRUE); + } + + /* + Check if we're trying to take a write lock in a read only transaction. + + Note that we allow write locks on log tables as otherwise logging + to general/slow log would be disabled in read only transactions. + */ + if (table_list->mdl_request.is_write_lock_request() && + thd->tx_read_only && + !(flags & (MYSQL_LOCK_LOG_TABLE | MYSQL_OPEN_HAS_MDL_LOCK))) + { + my_error(ER_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION, MYF(0)); + DBUG_RETURN(true); + } + + if (!table_list->db.str) + { + my_error(ER_NO_DB_ERROR, MYF(0)); + DBUG_RETURN(true); + } + + key_length= get_table_def_key(table_list, &key); + + /* + If we're in pre-locked or LOCK TABLES mode, let's try to find the + requested table in the list of pre-opened and locked tables. If the + table is not there, return an error - we can't open not pre-opened + tables in pre-locked/LOCK TABLES mode. + TODO: move this block into a separate function. + */ + if (thd->locked_tables_mode && + ! (flags & MYSQL_OPEN_GET_NEW_TABLE)) + { // Using table locks + TABLE *best_table= 0; + int best_distance= INT_MIN; + for (table=thd->open_tables; table ; table=table->next) + { + if (table->s->table_cache_key.length == key_length && + !memcmp(table->s->table_cache_key.str, key, key_length)) + { + if (!my_strcasecmp(system_charset_info, table->alias.c_ptr(), alias) && + table->query_id != thd->query_id && /* skip tables already used */ + (thd->locked_tables_mode == LTM_LOCK_TABLES || + table->query_id == 0)) + { + int distance= ((int) table->reginfo.lock_type - + (int) table_list->lock_type); + + /* + Find a table that either has the exact lock type requested, + or has the best suitable lock. In case there is no locked + table that has an equal or higher lock than requested, + we us the closest matching lock to be able to produce an error + message about wrong lock mode on the table. The best_table + is changed if bd < 0 <= d or bd < d < 0 or 0 <= d < bd. + + distance < 0 - No suitable lock found + distance > 0 - we have lock mode higher then we require + distance == 0 - we have lock mode exactly which we need + */ + if ((best_distance < 0 && distance > best_distance) || + (distance >= 0 && distance < best_distance)) + { + best_distance= distance; + best_table= table; + if (best_distance == 0) + { + /* + We have found a perfect match and can finish iterating + through open tables list. Check for table use conflict + between calling statement and SP/trigger is done in + lock_tables(). + */ + break; + } + } + } + } + } + if (best_table) + { + table= best_table; + table->query_id= thd->query_id; + table->init(thd, table_list); + DBUG_PRINT("info",("Using locked table")); +#ifdef WITH_PARTITION_STORAGE_ENGINE + part_names_error= set_partitions_as_used(table_list, table); +#endif + goto reset; + } + + if (is_locked_view(thd, table_list)) + { + if (table_list->sequence) + { + my_error(ER_NOT_SEQUENCE, MYF(0), table_list->db.str, table_list->alias.str); + DBUG_RETURN(true); + } + DBUG_RETURN(FALSE); // VIEW + } + + /* + No table in the locked tables list. In case of explicit LOCK TABLES + this can happen if a user did not include the table into the list. + In case of pre-locked mode locked tables list is generated automatically, + so we may only end up here if the table did not exist when + locked tables list was created. + */ + if (thd->locked_tables_mode == LTM_PRELOCKED) + my_error(ER_NO_SUCH_TABLE, MYF(0), table_list->db.str, table_list->alias.str); + else + my_error(ER_TABLE_NOT_LOCKED, MYF(0), alias); + DBUG_RETURN(TRUE); + } + + /* + Non pre-locked/LOCK TABLES mode, and the table is not temporary. + This is the normal use case. + */ + + if (! (flags & MYSQL_OPEN_HAS_MDL_LOCK)) + { + if (open_table_get_mdl_lock(thd, ot_ctx, &table_list->mdl_request, + flags, &mdl_ticket) || + mdl_ticket == NULL) + { + DEBUG_SYNC(thd, "before_open_table_wait_refresh"); + DBUG_RETURN(TRUE); + } + DEBUG_SYNC(thd, "after_open_table_mdl_shared"); + } + else + { + /* + Grab reference to the MDL lock ticket that was acquired + by the caller. + */ + mdl_ticket= table_list->mdl_request.ticket; + } + + if (table_list->open_strategy == TABLE_LIST::OPEN_IF_EXISTS) + { + if (!ha_table_exists(thd, &table_list->db, &table_list->table_name)) + DBUG_RETURN(FALSE); + } + else if (table_list->open_strategy == TABLE_LIST::OPEN_STUB) + DBUG_RETURN(FALSE); + + /* Table exists. Let us try to open it. */ + + if (table_list->i_s_requested_object & OPEN_TABLE_ONLY) + gts_flags= GTS_TABLE; + else if (table_list->i_s_requested_object & OPEN_VIEW_ONLY) + gts_flags= GTS_VIEW; + else + gts_flags= GTS_TABLE | GTS_VIEW; + +retry_share: + + share= tdc_acquire_share(thd, table_list, gts_flags, &table); + + if (unlikely(!share)) + { + /* + Hide "Table doesn't exist" errors if the table belongs to a view. + The check for thd->is_error() is necessary to not push an + unwanted error in case the error was already silenced. + @todo Rework the alternative ways to deal with ER_NO_SUCH TABLE. + */ + if (thd->is_error()) + { + if (table_list->parent_l) + { + thd->clear_error(); + my_error(ER_WRONG_MRG_TABLE, MYF(0)); + } + else if (table_list->belong_to_view) + { + TABLE_LIST *view= table_list->belong_to_view; + thd->clear_error(); + my_error(ER_VIEW_INVALID, MYF(0), + view->view_db.str, view->view_name.str); + } + } + DBUG_RETURN(TRUE); + } + + /* + Check if this TABLE_SHARE-object corresponds to a view. Note, that there is + no need to check TABLE_SHARE::tdc.flushed as we do for regular tables, + because view shares are always up to date. + */ + if (share->is_view) + { + /* + If parent_l of the table_list is non null then a merge table + has this view as child table, which is not supported. + */ + if (table_list->parent_l) + { + my_error(ER_WRONG_MRG_TABLE, MYF(0)); + goto err_lock; + } + if (table_list->sequence) + { + my_error(ER_NOT_SEQUENCE, MYF(0), table_list->db.str, + table_list->alias.str); + goto err_lock; + } + /* + This table is a view. Validate its metadata version: in particular, + that it was a view when the statement was prepared. + */ + if (check_and_update_table_version(thd, table_list, share)) + goto err_lock; + + /* Open view */ + if (mysql_make_view(thd, share, table_list, false)) + goto err_lock; + + /* TODO: Don't free this */ + tdc_release_share(share); + + DBUG_ASSERT(table_list->view); + + DBUG_RETURN(FALSE); + } + +#ifdef WITH_WSREP + if (!((flags & MYSQL_OPEN_IGNORE_FLUSH) || + (thd->wsrep_applier))) +#else + if (!(flags & MYSQL_OPEN_IGNORE_FLUSH)) +#endif + { + if (share->tdc->flushed) + { + /* + We already have an MDL lock. But we have encountered an old + version of table in the table definition cache which is possible + when someone changes the table version directly in the cache + without acquiring a metadata lock (e.g. this can happen during + "rolling" FLUSH TABLE(S)). + Release our reference to share, wait until old version of + share goes away and then try to get new version of table share. + */ + if (table) + tc_release_table(table); + else + tdc_release_share(share); + + MDL_deadlock_handler mdl_deadlock_handler(ot_ctx); + bool wait_result; + + thd->push_internal_handler(&mdl_deadlock_handler); + wait_result= tdc_wait_for_old_version(thd, table_list->db.str, + table_list->table_name.str, + ot_ctx->get_timeout(), + mdl_ticket->get_deadlock_weight()); + thd->pop_internal_handler(); + + if (wait_result) + DBUG_RETURN(TRUE); + + goto retry_share; + } + + if (thd->open_tables && thd->open_tables->s->tdc->flushed) + { + /* + If the version changes while we're opening the tables, + we have to back off, close all the tables opened-so-far, + and try to reopen them. Note: refresh_version is currently + changed only during FLUSH TABLES. + */ + if (table) + tc_release_table(table); + else + tdc_release_share(share); + (void)ot_ctx->request_backoff_action(Open_table_context::OT_REOPEN_TABLES, + NULL); + DBUG_RETURN(TRUE); + } + } + + if (table) + { + DBUG_ASSERT(table->file != NULL); + if (table->file->discover_check_version()) + { + tc_release_table(table); + (void) ot_ctx->request_backoff_action(Open_table_context::OT_DISCOVER, + table_list); + DBUG_RETURN(TRUE); + } + table->file->rebind_psi(); +#ifdef WITH_PARTITION_STORAGE_ENGINE + part_names_error= set_partitions_as_used(table_list, table); +#endif + } + else + { + enum open_frm_error error; + /* make a new table */ + if (!(table=(TABLE*) my_malloc(key_memory_TABLE, sizeof(*table), + MYF(MY_WME)))) + goto err_lock; + + error= open_table_from_share(thd, share, &table_list->alias, + HA_OPEN_KEYFILE | HA_TRY_READ_ONLY, + EXTRA_RECORD, + thd->open_options, table, FALSE, + IF_PARTITIONING(table_list->partition_names,0)); + + if (unlikely(error)) + { + my_free(table); + + if (error == OPEN_FRM_DISCOVER) + (void) ot_ctx->request_backoff_action(Open_table_context::OT_DISCOVER, + table_list); + else if (share->crashed) + { + if (!(flags & MYSQL_OPEN_IGNORE_REPAIR)) + (void) ot_ctx->request_backoff_action(Open_table_context::OT_REPAIR, + table_list); + else + table_list->crashed= 1; /* Mark that table was crashed */ + } + goto err_lock; + } + if (open_table_entry_fini(thd, share, table)) + { + closefrm(table); + my_free(table); + goto err_lock; + } + + /* Add table to the share's used tables list. */ + tc_add_table(thd, table); + } + + if (!(flags & MYSQL_OPEN_HAS_MDL_LOCK) && + table->s->table_category < TABLE_CATEGORY_INFORMATION) + { + /* + We are not under LOCK TABLES and going to acquire write-lock/ + modify the base table. We need to acquire protection against + global read lock until end of this statement in order to have + this statement blocked by active FLUSH TABLES WITH READ LOCK. + + We don't need to acquire this protection under LOCK TABLES as + such protection already acquired at LOCK TABLES time and + not released until UNLOCK TABLES. + + We don't block statements which modify only temporary tables + as these tables are not preserved by any form of + backup which uses FLUSH TABLES WITH READ LOCK. + + TODO: The fact that we sometimes acquire protection against + GRL only when we encounter table to be write-locked + slightly increases probability of deadlock. + This problem will be solved once Alik pushes his + temporary table refactoring patch and we can start + pre-acquiring metadata locks at the beggining of + open_tables() call. + */ + enum enum_mdl_type mdl_type= MDL_BACKUP_DML; + + if (table->s->table_category != TABLE_CATEGORY_USER) + mdl_type= MDL_BACKUP_SYS_DML; + else if (table->s->online_backup) + mdl_type= MDL_BACKUP_TRANS_DML; + + if (table_list->mdl_request.is_write_lock_request() && + ! (flags & (MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK | + MYSQL_OPEN_FORCE_SHARED_MDL | + MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL | + MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK)) && + ! ot_ctx->has_protection_against_grl(mdl_type)) + { + MDL_request protection_request; + MDL_deadlock_handler mdl_deadlock_handler(ot_ctx); + + if (thd->has_read_only_protection()) + { + MYSQL_UNBIND_TABLE(table->file); + tc_release_table(table); + DBUG_RETURN(TRUE); + } + + MDL_REQUEST_INIT(&protection_request, MDL_key::BACKUP, "", "", mdl_type, + MDL_STATEMENT); + + /* + Install error handler which if possible will convert deadlock error + into request to back-off and restart process of opening tables. + */ + thd->push_internal_handler(&mdl_deadlock_handler); + bool result= thd->mdl_context.acquire_lock(&protection_request, + ot_ctx->get_timeout()); + thd->pop_internal_handler(); + + if (result) + { + MYSQL_UNBIND_TABLE(table->file); + tc_release_table(table); + DBUG_RETURN(TRUE); + } + + ot_ctx->set_has_protection_against_grl(mdl_type); + } + } + + table->mdl_ticket= mdl_ticket; + table->reginfo.lock_type=TL_READ; /* Assume read */ + + table->init(thd, table_list); + + table->next= thd->open_tables; /* Link into simple list */ + thd->set_open_tables(table); + + reset: + /* + Check that there is no reference to a condition from an earlier query + (cf. Bug#58553). + */ + DBUG_ASSERT(table->file->pushed_cond == NULL); + table_list->updatable= 1; // It is not derived table nor non-updatable VIEW + table_list->table= table; + +#ifdef WITH_PARTITION_STORAGE_ENGINE + if (unlikely(table->part_info)) + { + /* Partitions specified were incorrect.*/ + if (part_names_error) + { + table->file->print_error(part_names_error, MYF(0)); + DBUG_RETURN(true); + } + } + else if (table_list->partition_names) + { + /* Don't allow PARTITION () clause on a nonpartitioned table */ + my_error(ER_PARTITION_CLAUSE_ON_NONPARTITIONED, MYF(0)); + DBUG_RETURN(true); + } +#endif + if (table_list->sequence && table->s->table_type != TABLE_TYPE_SEQUENCE) + { + my_error(ER_NOT_SEQUENCE, MYF(0), table_list->db.str, table_list->alias.str); + DBUG_RETURN(true); + } + + DBUG_ASSERT(thd->locked_tables_mode || table->file->row_logging == 0); + DBUG_RETURN(false); + +err_lock: + tdc_release_share(share); + + DBUG_PRINT("exit", ("failed")); + DBUG_RETURN(true); +} + + +/** + Find table in the list of open tables. + + @param list List of TABLE objects to be inspected. + @param db Database name + @param table_name Table name + + @return Pointer to the TABLE object found, 0 if no table found. +*/ + +TABLE *find_locked_table(TABLE *list, const char *db, const char *table_name) +{ + char key[MAX_DBKEY_LENGTH]; + uint key_length= tdc_create_key(key, db, table_name); + + for (TABLE *table= list; table ; table=table->next) + { + if (table->s->table_cache_key.length == key_length && + !memcmp(table->s->table_cache_key.str, key, key_length)) + return table; + } + return(0); +} + + +/** + Find instance of TABLE with upgradable or exclusive metadata + lock from the list of open tables, emit error if no such table + found. + + @param thd Thread context + @param db Database name. + @param table_name Name of table. + @param p_error In the case of an error (when the function returns NULL) + the error number is stored there. + If the p_error is NULL, function launches the error itself. + + @note This function checks if the connection holds a global IX + metadata lock. If no such lock is found, it is not safe to + upgrade the lock and ER_TABLE_NOT_LOCKED_FOR_WRITE will be + reported. + + @return Pointer to TABLE instance with MDL_SHARED_UPGRADABLE + MDL_SHARED_NO_WRITE, MDL_SHARED_NO_READ_WRITE, or + MDL_EXCLUSIVE metadata lock, NULL otherwise. +*/ + +TABLE *find_table_for_mdl_upgrade(THD *thd, const char *db, + const char *table_name, int *p_error) +{ + TABLE *tab= find_locked_table(thd->open_tables, db, table_name); + int error; + + if (unlikely(!tab)) + { + error= ER_TABLE_NOT_LOCKED; + goto err_exit; + } + + /* + It is not safe to upgrade the metadata lock without a global IX lock. + This can happen with FLUSH TABLES <list> WITH READ LOCK as we in these + cases don't take a global IX lock in order to be compatible with + global read lock. + */ + if (unlikely(!thd->mdl_context.is_lock_owner(MDL_key::BACKUP, "", "", + MDL_BACKUP_DDL))) + { + error= ER_TABLE_NOT_LOCKED_FOR_WRITE; + goto err_exit; + } + + while (tab->mdl_ticket != NULL && + !tab->mdl_ticket->is_upgradable_or_exclusive() && + (tab= find_locked_table(tab->next, db, table_name))) + continue; + + if (unlikely(!tab)) + { + error= ER_TABLE_NOT_LOCKED_FOR_WRITE; + goto err_exit; + } + + return tab; + +err_exit: + if (p_error) + *p_error= error; + else + my_error(error, MYF(0), table_name); + + return NULL; +} + + +/*********************************************************************** + class Locked_tables_list implementation. Declared in sql_class.h +************************************************************************/ + +/** + Enter LTM_LOCK_TABLES mode. + + Enter the LOCK TABLES mode using all the tables that are + currently open and locked in this connection. + Initializes a TABLE_LIST instance for every locked table. + + @param thd thread handle + + @return TRUE if out of memory. +*/ + +bool +Locked_tables_list::init_locked_tables(THD *thd) +{ + DBUG_ASSERT(thd->locked_tables_mode == LTM_NONE); + DBUG_ASSERT(m_locked_tables == NULL); + DBUG_ASSERT(m_reopen_array == NULL); + DBUG_ASSERT(m_locked_tables_count == 0); + + for (TABLE *table= thd->open_tables; table; + table= table->next, m_locked_tables_count++) + { + TABLE_LIST *src_table_list= table->pos_in_table_list; + LEX_CSTRING db, table_name, alias; + + db.length= table->s->db.length; + table_name.length= table->s->table_name.length; + alias.length= table->alias.length(); + TABLE_LIST *dst_table_list; + + if (! multi_alloc_root(&m_locked_tables_root, + &dst_table_list, sizeof(*dst_table_list), + &db.str, (size_t) db.length + 1, + &table_name.str, (size_t) table_name.length + 1, + &alias.str, (size_t) alias.length + 1, + NullS)) + { + reset(); + return TRUE; + } + + memcpy((char*) db.str, table->s->db.str, db.length + 1); + memcpy((char*) table_name.str, table->s->table_name.str, + table_name.length + 1); + memcpy((char*) alias.str, table->alias.c_ptr(), alias.length + 1); + dst_table_list->init_one_table(&db, &table_name, + &alias, table->reginfo.lock_type); + dst_table_list->table= table; + dst_table_list->mdl_request.ticket= src_table_list->mdl_request.ticket; + + /* Link last into the list of tables */ + *(dst_table_list->prev_global= m_locked_tables_last)= dst_table_list; + m_locked_tables_last= &dst_table_list->next_global; + table->pos_in_locked_tables= dst_table_list; + } + if (m_locked_tables_count) + { + /** + Allocate an auxiliary array to pass to mysql_lock_tables() + in reopen_tables(). reopen_tables() is a critical + path and we don't want to complicate it with extra allocations. + */ + m_reopen_array= (TABLE_LIST**)alloc_root(&m_locked_tables_root, + sizeof(TABLE_LIST*) * + (m_locked_tables_count+1)); + if (m_reopen_array == NULL) + { + reset(); + return TRUE; + } + } + + TRANSACT_TRACKER(add_trx_state(thd, TX_LOCKED_TABLES)); + + thd->enter_locked_tables_mode(LTM_LOCK_TABLES); + + return FALSE; +} + + +/** + Leave LTM_LOCK_TABLES mode if it's been entered. + + Close all locked tables, free memory, and leave the mode. + + @note This function is a no-op if we're not in LOCK TABLES. +*/ + +int +Locked_tables_list::unlock_locked_tables(THD *thd) +{ + int error; + DBUG_ASSERT(!thd->in_sub_stmt && + !(thd->state_flags & Open_tables_state::BACKUPS_AVAIL)); + /* + Sic: we must be careful to not close open tables if + we're not in LOCK TABLES mode: unlock_locked_tables() is + sometimes called implicitly, expecting no effect on + open tables, e.g. from begin_trans(). + */ + if (thd->locked_tables_mode != LTM_LOCK_TABLES) + return 0; + + for (TABLE_LIST *table_list= m_locked_tables; + table_list; table_list= table_list->next_global) + { + /* + Clear the position in the list, the TABLE object will be + returned to the table cache. + */ + if (table_list->table) // If not closed + table_list->table->pos_in_locked_tables= NULL; + } + thd->leave_locked_tables_mode(); + + TRANSACT_TRACKER(clear_trx_state(thd, TX_LOCKED_TABLES)); + + DBUG_ASSERT(thd->transaction->stmt.is_empty()); + error= close_thread_tables(thd); + + /* + We rely on the caller to implicitly commit the + transaction and release transactional locks. + */ + + /* + After closing tables we can free memory used for storing lock + request for metadata locks and TABLE_LIST elements. + */ + reset(); + return error; +} + + +/** + Remove all meta data locks associated with table and release locked + table mode if there is no locked tables anymore +*/ + +int +Locked_tables_list::unlock_locked_table(THD *thd, MDL_ticket *mdl_ticket) +{ + /* + Ensure we are in locked table mode. + As this function is only called on error condition it's better + to check this condition here than in the caller. + */ + if (thd->locked_tables_mode != LTM_LOCK_TABLES) + return 0; + + if (mdl_ticket) + { + /* + Under LOCK TABLES we may have several instances of table open + and locked and therefore have to remove several metadata lock + requests associated with them. + */ + thd->mdl_context.release_all_locks_for_name(mdl_ticket); + } + + if (thd->lock->table_count == 0) + return unlock_locked_tables(thd); + return 0; +} + + +/* + Free memory allocated for storing locks +*/ + +void Locked_tables_list::reset() +{ + free_root(&m_locked_tables_root, MYF(0)); + m_locked_tables= NULL; + m_locked_tables_last= &m_locked_tables; + m_reopen_array= NULL; + m_locked_tables_count= 0; + some_table_marked_for_reopen= 0; +} + + +/** + Unlink a locked table from the locked tables list, either + temporarily or permanently. + + @param thd thread handle + @param table_list the element of locked tables list. + The implementation assumes that this argument + points to a TABLE_LIST element linked into + the locked tables list. Passing a TABLE_LIST + instance that is not part of locked tables + list will lead to a crash. + @param remove_from_locked_tables + TRUE if the table is removed from the list + permanently. + + This function is a no-op if we're not under LOCK TABLES. + + @sa Locked_tables_list::reopen_tables() +*/ + + +void Locked_tables_list::unlink_from_list(THD *thd, + TABLE_LIST *table_list, + bool remove_from_locked_tables) +{ + /* + If mode is not LTM_LOCK_TABLES, we needn't do anything. Moreover, + outside this mode pos_in_locked_tables value is not trustworthy. + */ + if (thd->locked_tables_mode != LTM_LOCK_TABLES && + thd->locked_tables_mode != LTM_PRELOCKED_UNDER_LOCK_TABLES) + return; + + /* + table_list must be set and point to pos_in_locked_tables of some + table. + */ + DBUG_ASSERT(table_list->table->pos_in_locked_tables == table_list); + + /* Clear the pointer, the table will be returned to the table cache. */ + table_list->table->pos_in_locked_tables= NULL; + + /* Mark the table as closed in the locked tables list. */ + table_list->table= NULL; + + /* + If the table is being dropped or renamed, remove it from + the locked tables list (implicitly drop the LOCK TABLES lock + on it). + */ + if (remove_from_locked_tables) + { + *table_list->prev_global= table_list->next_global; + if (table_list->next_global == NULL) + m_locked_tables_last= table_list->prev_global; + else + table_list->next_global->prev_global= table_list->prev_global; + m_locked_tables_count--; + } +} + +/** + This is an attempt to recover (somewhat) in case of an error. + If we failed to reopen a closed table, let's unlink it from the + list and forget about it. From a user perspective that would look + as if the server "lost" the lock on one of the locked tables. + + @note This function is a no-op if we're not under LOCK TABLES. +*/ + +void Locked_tables_list:: +unlink_all_closed_tables(THD *thd, MYSQL_LOCK *lock, size_t reopen_count) +{ + /* If we managed to take a lock, unlock tables and free the lock. */ + if (lock) + mysql_unlock_tables(thd, lock); + /* + If a failure happened in reopen_tables(), we may have succeeded + reopening some tables, but not all. + This works when the connection was killed in mysql_lock_tables(). + */ + if (reopen_count) + { + while (reopen_count--) + { + /* + When closing the table, we must remove it + from thd->open_tables list. + We rely on the fact that open_table() that was used + in reopen_tables() always links the opened table + to the beginning of the open_tables list. + */ + DBUG_ASSERT(thd->open_tables == m_reopen_array[reopen_count]->table); + + thd->open_tables->pos_in_locked_tables->table= NULL; + thd->open_tables->pos_in_locked_tables= NULL; + + close_thread_table(thd, &thd->open_tables); + } + } + /* Exclude all closed tables from the LOCK TABLES list. */ + for (TABLE_LIST *table_list= m_locked_tables; table_list; table_list= + table_list->next_global) + { + if (table_list->table == NULL) + { + /* Unlink from list. */ + *table_list->prev_global= table_list->next_global; + if (table_list->next_global == NULL) + m_locked_tables_last= table_list->prev_global; + else + table_list->next_global->prev_global= table_list->prev_global; + m_locked_tables_count--; + } + } + + /* If no tables left, do an automatic UNLOCK TABLES */ + if (thd->lock && thd->lock->table_count == 0) + { + /* + We have to rollback any open transactions here. + This is required in the case where the server has been killed + but some transations are still open (as part of locked tables). + If we don't do this, we will get an assert in unlock_locked_tables(). + */ + ha_rollback_trans(thd, FALSE); + ha_rollback_trans(thd, TRUE); + unlock_locked_tables(thd); + } +} + + +/* + Mark all instances of the table to be reopened + + This is only needed when LOCK TABLES is active +*/ + +void Locked_tables_list::mark_table_for_reopen(THD *thd, TABLE *table) +{ + TABLE_SHARE *share= table->s; + + for (TABLE_LIST *table_list= m_locked_tables; + table_list; table_list= table_list->next_global) + { + if (table_list->table->s == share) + table_list->table->internal_set_needs_reopen(true); + } + /* This is needed in the case where lock tables where not used */ + table->internal_set_needs_reopen(true); + some_table_marked_for_reopen= 1; +} + + +/** + Reopen the tables locked with LOCK TABLES and temporarily closed + by a DDL statement or FLUSH TABLES. + + @param need_reopen If set, reopen open tables that are marked with + for reopen. + If not set, reopen tables that where closed. + + @note This function is a no-op if we're not under LOCK TABLES. + + @return TRUE if an error reopening the tables. May happen in + case of some fatal system error only, e.g. a disk + corruption, out of memory or a serious bug in the + locking. +*/ + +bool +Locked_tables_list::reopen_tables(THD *thd, bool need_reopen) +{ + Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN); + uint reopen_count= 0; + MYSQL_LOCK *lock; + MYSQL_LOCK *merged_lock; + DBUG_ENTER("Locked_tables_list::reopen_tables"); + + DBUG_ASSERT(some_table_marked_for_reopen || !need_reopen); + + + /* Reset flag that some table was marked for reopen */ + if (need_reopen) + some_table_marked_for_reopen= 0; + + for (TABLE_LIST *table_list= m_locked_tables; + table_list; table_list= table_list->next_global) + { + if (need_reopen) + { + if (!table_list->table || !table_list->table->needs_reopen()) + continue; + for (TABLE **prev= &thd->open_tables; *prev; prev= &(*prev)->next) + { + if (*prev == table_list->table) + { + thd->locked_tables_list.unlink_from_list(thd, table_list, false); + mysql_lock_remove(thd, thd->lock, *prev); + (*prev)->file->extra(HA_EXTRA_PREPARE_FOR_FORCED_CLOSE); + close_thread_table(thd, prev); + break; + } + } + DBUG_ASSERT(table_list->table == NULL); + } + else + { + if (table_list->table) /* The table was not closed */ + continue; + } + + DBUG_ASSERT(reopen_count < m_locked_tables_count); + m_reopen_array[reopen_count++]= table_list; + } + if (reopen_count) + { + TABLE **tables= (TABLE**) my_alloca(reopen_count * sizeof(TABLE*)); + + for (uint i= 0 ; i < reopen_count ; i++) + { + TABLE_LIST *table_list= m_reopen_array[i]; + /* Links into thd->open_tables upon success */ + if (open_table(thd, table_list, &ot_ctx)) + { + unlink_all_closed_tables(thd, 0, i); + my_afree((void*) tables); + DBUG_RETURN(TRUE); + } + tables[i]= table_list->table; + table_list->table->pos_in_locked_tables= table_list; + /* See also the comment on lock type in init_locked_tables(). */ + table_list->table->reginfo.lock_type= table_list->lock_type; + } + + thd->in_lock_tables= 1; + /* + We re-lock all tables with mysql_lock_tables() at once rather + than locking one table at a time because of the case + reported in Bug#45035: when the same table is present + in the list many times, thr_lock.c fails to grant READ lock + on a table that is already locked by WRITE lock, even if + WRITE lock is taken by the same thread. If READ and WRITE + lock are passed to thr_lock.c in the same list, everything + works fine. Patching legacy code of thr_lock.c is risking to + break something else. + */ + lock= mysql_lock_tables(thd, tables, reopen_count, + MYSQL_OPEN_REOPEN | MYSQL_LOCK_USE_MALLOC); + thd->in_lock_tables= 0; + if (lock == NULL || (merged_lock= + mysql_lock_merge(thd->lock, lock)) == NULL) + { + unlink_all_closed_tables(thd, lock, reopen_count); + if (! thd->killed) + my_error(ER_LOCK_DEADLOCK, MYF(0)); + my_afree((void*) tables); + DBUG_RETURN(TRUE); + } + thd->lock= merged_lock; + my_afree((void*) tables); + } + DBUG_RETURN(FALSE); +} + +/** + Add back a locked table to the locked list that we just removed from it. + This is needed in CREATE OR REPLACE TABLE where we are dropping, creating + and re-opening a locked table. + + @return 0 0k + @return 1 error +*/ + +bool Locked_tables_list::restore_lock(THD *thd, TABLE_LIST *dst_table_list, + TABLE *table, MYSQL_LOCK *lock) +{ + MYSQL_LOCK *merged_lock; + DBUG_ENTER("restore_lock"); + DBUG_ASSERT(!strcmp(dst_table_list->table_name.str, table->s->table_name.str)); + + /* Ensure we have the memory to add the table back */ + if (!(merged_lock= mysql_lock_merge(thd->lock, lock))) + DBUG_RETURN(1); + thd->lock= merged_lock; + + /* Link to the new table */ + dst_table_list->table= table; + /* + The lock type may have changed (normally it should not as create + table will lock the table in write mode + */ + dst_table_list->lock_type= table->reginfo.lock_type; + table->pos_in_locked_tables= dst_table_list; + + add_back_last_deleted_lock(dst_table_list); + + table->mdl_ticket->downgrade_lock(table->reginfo.lock_type >= + TL_WRITE_ALLOW_WRITE ? + MDL_SHARED_NO_READ_WRITE : + MDL_SHARED_READ); + + DBUG_RETURN(0); +} + +/* + Add back the last deleted lock structure. + This should be followed by a call to reopen_tables() to + open the table. +*/ + +void Locked_tables_list::add_back_last_deleted_lock(TABLE_LIST *dst_table_list) +{ + /* Link the lock back in the locked tables list */ + dst_table_list->prev_global= m_locked_tables_last; + *m_locked_tables_last= dst_table_list; + m_locked_tables_last= &dst_table_list->next_global; + dst_table_list->next_global= 0; + m_locked_tables_count++; +} + + +#ifndef DBUG_OFF +/* Cause a spurious statement reprepare for debug purposes. */ +static bool inject_reprepare(THD *thd) +{ + if (thd->m_reprepare_observer && thd->stmt_arena->is_reprepared == FALSE) + { + thd->m_reprepare_observer->report_error(thd); + return TRUE; + } + + return FALSE; +} +#endif + +/** + Compare metadata versions of an element obtained from the table + definition cache and its corresponding node in the parse tree. + + @details If the new and the old values mismatch, invoke + Metadata_version_observer. + At prepared statement prepare, all TABLE_LIST version values are + NULL and we always have a mismatch. But there is no observer set + in THD, and therefore no error is reported. Instead, we update + the value in the parse tree, effectively recording the original + version. + At prepared statement execute, an observer may be installed. If + there is a version mismatch, we push an error and return TRUE. + + For conventional execution (no prepared statements), the + observer is never installed. + + @sa Execute_observer + @sa check_prepared_statement() to see cases when an observer is installed + @sa TABLE_LIST::is_table_ref_id_equal() + @sa TABLE_SHARE::get_table_ref_id() + + @param[in] thd used to report errors + @param[in,out] tables TABLE_LIST instance created by the parser + Metadata version information in this object + is updated upon success. + @param[in] table_share an element from the table definition cache + + @retval TRUE an error, which has been reported + @retval FALSE success, version in TABLE_LIST has been updated +*/ + +static bool +check_and_update_table_version(THD *thd, + TABLE_LIST *tables, TABLE_SHARE *table_share) +{ + if (! tables->is_table_ref_id_equal(table_share)) + { + if (thd->m_reprepare_observer && + thd->m_reprepare_observer->report_error(thd)) + { + /* + Version of the table share is different from the + previous execution of the prepared statement, and it is + unacceptable for this SQLCOM. Error has been reported. + */ + DBUG_ASSERT(thd->is_error()); + return TRUE; + } + /* Always maintain the latest version and type */ + tables->set_table_ref_id(table_share); + } + + DBUG_EXECUTE_IF("reprepare_each_statement", return inject_reprepare(thd);); + return FALSE; +} + + +/** + Compares versions of a stored routine obtained from the sp cache + and the version used at prepare. + + @details If the new and the old values mismatch, invoke + Metadata_version_observer. + At prepared statement prepare, all Sroutine_hash_entry version values + are NULL and we always have a mismatch. But there is no observer set + in THD, and therefore no error is reported. Instead, we update + the value in Sroutine_hash_entry, effectively recording the original + version. + At prepared statement execute, an observer may be installed. If + there is a version mismatch, we push an error and return TRUE. + + For conventional execution (no prepared statements), the + observer is never installed. + + @param[in] thd used to report errors + @param[in/out] rt pointer to stored routine entry in the + parse tree + @param[in] sp pointer to stored routine cache entry. + Can be NULL if there is no such routine. + @retval TRUE an error, which has been reported + @retval FALSE success, version in Sroutine_hash_entry has been updated +*/ + +static bool +check_and_update_routine_version(THD *thd, Sroutine_hash_entry *rt, + sp_head *sp) +{ + ulong spc_version= sp_cache_version(); + /* sp is NULL if there is no such routine. */ + ulong version= sp ? sp->sp_cache_version() : spc_version; + /* + If the version in the parse tree is stale, + or the version in the cache is stale and sp is not used, + we need to reprepare. + Sic: version != spc_version <--> sp is not NULL. + */ + if (rt->m_sp_cache_version != version || + (version != spc_version && !sp->is_invoked())) + { + if (thd->m_reprepare_observer && + thd->m_reprepare_observer->report_error(thd)) + { + /* + Version of the sp cache is different from the + previous execution of the prepared statement, and it is + unacceptable for this SQLCOM. Error has been reported. + */ + DBUG_ASSERT(thd->is_error()); + return TRUE; + } + /* Always maintain the latest cache version. */ + rt->m_sp_cache_version= version; + } + return FALSE; +} + + +/** + Open view by getting its definition from disk (and table cache in future). + + @param thd Thread handle + @param table_list TABLE_LIST with db, table_name & belong_to_view + @param flags Flags which modify how we open the view + + @todo This function is needed for special handling of views under + LOCK TABLES. We probably should get rid of it in long term. + + @return FALSE if success, TRUE - otherwise. +*/ + +bool tdc_open_view(THD *thd, TABLE_LIST *table_list, uint flags) +{ + TABLE not_used; + TABLE_SHARE *share; + bool err= TRUE; + + if (!(share= tdc_acquire_share(thd, table_list, GTS_VIEW))) + return TRUE; + + DBUG_ASSERT(share->is_view); + + if (flags & CHECK_METADATA_VERSION) + { + /* + Check TABLE_SHARE-version of view only if we have been instructed to do + so. We do not need to check the version if we're executing CREATE VIEW or + ALTER VIEW statements. + + In the future, this functionality should be moved out from + tdc_open_view(), and tdc_open_view() should became a part of a clean + table-definition-cache interface. + */ + if (check_and_update_table_version(thd, table_list, share)) + goto ret; + } + + err= mysql_make_view(thd, share, table_list, (flags & OPEN_VIEW_NO_PARSE)); +ret: + tdc_release_share(share); + + return err; +} + + +/** + Finalize the process of TABLE creation by loading table triggers + and taking action if a HEAP table content was emptied implicitly. +*/ + +static bool open_table_entry_fini(THD *thd, TABLE_SHARE *share, TABLE *entry) +{ + if (Table_triggers_list::check_n_load(thd, &share->db, + &share->table_name, entry, 0)) + return TRUE; + + /* + If we are here, there was no fatal error (but error may be still + unitialized). + */ + if (unlikely(entry->file->implicit_emptied)) + { + entry->file->implicit_emptied= 0; + if (mysql_bin_log.is_open()) + { + char query_buf[2*FN_REFLEN + 21]; + String query(query_buf, sizeof(query_buf), system_charset_info); + + query.length(0); + query.append("DELETE FROM "); + append_identifier(thd, &query, &share->db); + query.append("."); + append_identifier(thd, &query, &share->table_name); + + /* + we bypass thd->binlog_query() here, + as it does a lot of extra work, that is simply wrong in this case + */ + Query_log_event qinfo(thd, query.ptr(), query.length(), + FALSE, TRUE, TRUE, 0); + if (mysql_bin_log.write(&qinfo)) + return TRUE; + } + } + return FALSE; +} + + +/** + Auxiliary routine which is used for performing automatical table repair. +*/ + +static bool auto_repair_table(THD *thd, TABLE_LIST *table_list) +{ + TABLE_SHARE *share; + TABLE entry; + bool result= TRUE; + + thd->clear_error(); + + if (!(share= tdc_acquire_share(thd, table_list, GTS_TABLE))) + return result; + + DBUG_ASSERT(! share->is_view); + + if (open_table_from_share(thd, share, &table_list->alias, + HA_OPEN_KEYFILE | HA_TRY_READ_ONLY, + EXTRA_RECORD, + ha_open_options | HA_OPEN_FOR_REPAIR, + &entry, FALSE) || ! entry.file || + (entry.file->is_crashed() && entry.file->ha_check_and_repair(thd))) + { + /* Give right error message */ + thd->clear_error(); + my_error(ER_NOT_KEYFILE, MYF(0), share->table_name.str); + sql_print_error("Couldn't repair table: %s.%s", share->db.str, + share->table_name.str); + if (entry.file) + closefrm(&entry); + } + else + { + thd->clear_error(); // Clear error message + closefrm(&entry); + result= FALSE; + } + + tdc_remove_referenced_share(thd, share); + return result; +} + + +/** Open_table_context */ + +Open_table_context::Open_table_context(THD *thd, uint flags) + :m_thd(thd), + m_failed_table(NULL), + m_start_of_statement_svp(thd->mdl_context.mdl_savepoint()), + m_timeout(flags & MYSQL_LOCK_IGNORE_TIMEOUT ? + LONG_TIMEOUT : thd->variables.lock_wait_timeout), + m_flags(flags), + m_action(OT_NO_ACTION), + m_has_locks(thd->mdl_context.has_locks()), + m_has_protection_against_grl(0) +{} + + +/** + Check if we can back-off and set back off action if we can. + Otherwise report and return error. + + @retval TRUE if back-off is impossible. + @retval FALSE if we can back off. Back off action has been set. +*/ + +bool +Open_table_context:: +request_backoff_action(enum_open_table_action action_arg, + TABLE_LIST *table) +{ + /* + A back off action may be one of three kinds: + + * We met a broken table that needs repair, or a table that + is not present on this MySQL server and needs re-discovery. + To perform the action, we need an exclusive metadata lock on + the table. Acquiring X lock while holding other shared + locks can easily lead to deadlocks. We rely on MDL deadlock + detector to discover them. If this is a multi-statement + transaction that holds metadata locks for completed statements, + we should keep these locks after discovery/repair. + The action type in this case is OT_DISCOVER or OT_REPAIR. + * Our attempt to acquire an MDL lock lead to a deadlock, + detected by the MDL deadlock detector. The current + session was chosen a victim. If this is a multi-statement + transaction that holds metadata locks taken by completed + statements, restarting locking for the current statement + may lead to a livelock. Releasing locks of completed + statements can not be done as will lead to violation + of ACID. Thus, again, if m_has_locks is set, + we report an error. Otherwise, when there are no metadata + locks other than which belong to this statement, we can + try to recover from error by releasing all locks and + restarting the pre-locking. + Similarly, a deadlock error can occur when the + pre-locking process met a TABLE_SHARE that is being + flushed, and unsuccessfully waited for the flush to + complete. A deadlock in this case can happen, e.g., + when our session is holding a metadata lock that + is being waited on by a session which is using + the table which is being flushed. The only way + to recover from this error is, again, to close all + open tables, release all locks, and retry pre-locking. + Action type name is OT_REOPEN_TABLES. Re-trying + while holding some locks may lead to a livelock, + and thus we don't do it. + * Finally, this session has open TABLEs from different + "generations" of the table cache. This can happen, e.g., + when, after this session has successfully opened one + table used for a statement, FLUSH TABLES interfered and + expelled another table used in it. FLUSH TABLES then + blocks and waits on the table already opened by this + statement. + We detect this situation by ensuring that table cache + version of all tables used in a statement is the same. + If it isn't, all tables needs to be reopened. + Note, that we can always perform a reopen in this case, + even if we already have metadata locks, since we don't + keep tables open between statements and a livelock + is not possible. + */ + if (action_arg == OT_BACKOFF_AND_RETRY && m_has_locks) + { + my_error(ER_LOCK_DEADLOCK, MYF(0)); + m_thd->mark_transaction_to_rollback(true); + return TRUE; + } + /* + If auto-repair or discovery are requested, a pointer to table + list element must be provided. + */ + if (table) + { + DBUG_ASSERT(action_arg == OT_DISCOVER || action_arg == OT_REPAIR); + m_failed_table= (TABLE_LIST*) m_thd->alloc(sizeof(TABLE_LIST)); + if (m_failed_table == NULL) + return TRUE; + m_failed_table->init_one_table(&table->db, &table->table_name, &table->alias, TL_WRITE); + m_failed_table->open_strategy= table->open_strategy; + m_failed_table->mdl_request.set_type(MDL_EXCLUSIVE); + } + m_action= action_arg; + return FALSE; +} + + +/** + An error handler to mark transaction to rollback on DEADLOCK error + during DISCOVER / REPAIR. +*/ +class MDL_deadlock_discovery_repair_handler : public Internal_error_handler +{ +public: + virtual bool handle_condition(THD *thd, + uint sql_errno, + const char* sqlstate, + Sql_condition::enum_warning_level *level, + const char* msg, + Sql_condition ** cond_hdl) + { + if (sql_errno == ER_LOCK_DEADLOCK) + { + thd->mark_transaction_to_rollback(true); + } + /* + We have marked this transaction to rollback. Return false to allow + error to be reported or handled by other handlers. + */ + return false; + } +}; + +/** + Recover from failed attempt of open table by performing requested action. + + @pre This function should be called only with "action" != OT_NO_ACTION + and after having called @sa close_tables_for_reopen(). + + @retval FALSE - Success. One should try to open tables once again. + @retval TRUE - Error +*/ + +bool +Open_table_context::recover_from_failed_open() +{ + bool result= FALSE; + MDL_deadlock_discovery_repair_handler handler; + /* + Install error handler to mark transaction to rollback on DEADLOCK error. + */ + m_thd->push_internal_handler(&handler); + + /* Execute the action. */ + switch (m_action) + { + case OT_BACKOFF_AND_RETRY: + case OT_REOPEN_TABLES: + break; + case OT_DISCOVER: + case OT_REPAIR: + if ((result= lock_table_names(m_thd, m_thd->lex->create_info, + m_failed_table, NULL, + get_timeout(), 0))) + break; + + tdc_remove_table(m_thd, m_failed_table->db.str, + m_failed_table->table_name.str); + + switch (m_action) + { + case OT_DISCOVER: + { + m_thd->get_stmt_da()->clear_warning_info(m_thd->query_id); + m_thd->clear_error(); // Clear error message + + No_such_table_error_handler no_such_table_handler; + bool open_if_exists= m_failed_table->open_strategy == TABLE_LIST::OPEN_IF_EXISTS; + + if (open_if_exists) + m_thd->push_internal_handler(&no_such_table_handler); + + result= !tdc_acquire_share(m_thd, m_failed_table, + GTS_TABLE | GTS_FORCE_DISCOVERY | GTS_NOLOCK); + if (open_if_exists) + { + m_thd->pop_internal_handler(); + if (result && no_such_table_handler.safely_trapped_errors()) + result= FALSE; + } + break; + } + case OT_REPAIR: + result= auto_repair_table(m_thd, m_failed_table); + break; + case OT_BACKOFF_AND_RETRY: + case OT_REOPEN_TABLES: + case OT_NO_ACTION: + DBUG_ASSERT(0); + } + /* + Rollback to start of the current statement to release exclusive lock + on table which was discovered but preserve locks from previous statements + in current transaction. + */ + m_thd->mdl_context.rollback_to_savepoint(start_of_statement_svp()); + break; + case OT_NO_ACTION: + DBUG_ASSERT(0); + } + m_thd->pop_internal_handler(); + /* + Reset the pointers to conflicting MDL request and the + TABLE_LIST element, set when we need auto-discovery or repair, + for safety. + */ + m_failed_table= NULL; + /* + Reset flag indicating that we have already acquired protection + against GRL. It is no longer valid as the corresponding lock was + released by close_tables_for_reopen(). + */ + m_has_protection_against_grl= 0; + /* Prepare for possible another back-off. */ + m_action= OT_NO_ACTION; + return result; +} + + +/* + Return a appropriate read lock type given a table object. + + @param thd Thread context + @param prelocking_ctx Prelocking context. + @param table_list Table list element for table to be locked. + @param routine_modifies_data + Some routine that is invoked by statement + modifies data. + + @remark Due to a statement-based replication limitation, statements such as + INSERT INTO .. SELECT FROM .. and CREATE TABLE .. SELECT FROM need + to grab a TL_READ_NO_INSERT lock on the source table in order to + prevent the replication of a concurrent statement that modifies the + source table. If such a statement gets applied on the slave before + the INSERT .. SELECT statement finishes, data on the master could + differ from data on the slave and end-up with a discrepancy between + the binary log and table state. + This also applies to SELECT/SET/DO statements which use stored + functions. Calls to such functions are going to be logged as a + whole and thus should be serialized against concurrent changes + to tables used by those functions. This is avoided when functions + do not modify data but only read it, since in this case nothing is + written to the binary log. Argument routine_modifies_data + denotes the same. So effectively, if the statement is not a + update query and routine_modifies_data is false, then + prelocking_placeholder does not take importance. + + Furthermore, this does not apply to I_S and log tables as it's + always unsafe to replicate such tables under statement-based + replication as the table on the slave might contain other data + (ie: general_log is enabled on the slave). The statement will + be marked as unsafe for SBR in decide_logging_format(). + @remark Note that even in prelocked mode it is important to correctly + determine lock type value. In this mode lock type is passed to + handler::start_stmt() method and can be used by storage engine, + for example, to determine what kind of row locks it should acquire + when reading data from the table. +*/ + +thr_lock_type read_lock_type_for_table(THD *thd, + Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, + bool routine_modifies_data) +{ + /* + In cases when this function is called for a sub-statement executed in + prelocked mode we can't rely on OPTION_BIN_LOG flag in THD::options + bitmap to determine that binary logging is turned on as this bit can + be cleared before executing sub-statement. So instead we have to look + at THD::variables::sql_log_bin member. + */ + bool log_on= mysql_bin_log.is_open() && thd->variables.sql_log_bin; + if ((log_on == FALSE) || (thd->wsrep_binlog_format() == BINLOG_FORMAT_ROW) || + (table_list->table->s->table_category == TABLE_CATEGORY_LOG) || + (table_list->table->s->table_category == TABLE_CATEGORY_PERFORMANCE) || + !(is_update_query(prelocking_ctx->sql_command) || + (routine_modifies_data && table_list->prelocking_placeholder) || + (thd->locked_tables_mode > LTM_LOCK_TABLES))) + return TL_READ; + else + return TL_READ_NO_INSERT; +} + + +/* + Extend the prelocking set with tables and routines used by a routine. + + @param[in] thd Thread context. + @param[in] rt Element of prelocking set to be processed. + @param[in] ot_ctx Context of open_table used to recover from + locking failures. + @retval false Success. + @retval true Failure (Conflicting metadata lock, OOM, other errors). +*/ +static bool +sp_acquire_mdl(THD *thd, Sroutine_hash_entry *rt, Open_table_context *ot_ctx) +{ + DBUG_ENTER("sp_acquire_mdl"); + /* + Since we acquire only shared lock on routines we don't + need to care about global intention exclusive locks. + */ + DBUG_ASSERT(rt->mdl_request.type == MDL_SHARED); + + /* + Waiting for a conflicting metadata lock to go away may + lead to a deadlock, detected by MDL subsystem. + If possible, we try to resolve such deadlocks by releasing all + metadata locks and restarting the pre-locking process. + To prevent the error from polluting the diagnostics area + in case of successful resolution, install a special error + handler for ER_LOCK_DEADLOCK error. + */ + MDL_deadlock_handler mdl_deadlock_handler(ot_ctx); + + thd->push_internal_handler(&mdl_deadlock_handler); + bool result= thd->mdl_context.acquire_lock(&rt->mdl_request, + ot_ctx->get_timeout()); + thd->pop_internal_handler(); + + DBUG_RETURN(result); +} + + +/* + Handle element of prelocking set other than table. E.g. cache routine + and, if prelocking strategy prescribes so, extend the prelocking set + with tables and routines used by it. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context. + @param[in] rt Element of prelocking set to be processed. + @param[in] prelocking_strategy Strategy which specifies how the + prelocking set should be extended when + one of its elements is processed. + @param[in] has_prelocking_list Indicates that prelocking set/list for + this statement has already been built. + @param[in] ot_ctx Context of open_table used to recover from + locking failures. + @param[out] need_prelocking Set to TRUE if it was detected that this + statement will require prelocked mode for + its execution, not touched otherwise. + @param[out] routine_modifies_data Set to TRUE if it was detected that this + routine does modify table data. + + @retval FALSE Success. + @retval TRUE Failure (Conflicting metadata lock, OOM, other errors). +*/ + +static bool +open_and_process_routine(THD *thd, Query_tables_list *prelocking_ctx, + Sroutine_hash_entry *rt, + Prelocking_strategy *prelocking_strategy, + bool has_prelocking_list, + Open_table_context *ot_ctx, + bool *need_prelocking, bool *routine_modifies_data) +{ + MDL_key::enum_mdl_namespace mdl_type= rt->mdl_request.key.mdl_namespace(); + DBUG_ENTER("open_and_process_routine"); + + *routine_modifies_data= false; + + switch (mdl_type) + { + case MDL_key::PACKAGE_BODY: + DBUG_ASSERT(rt != (Sroutine_hash_entry*)prelocking_ctx->sroutines_list.first); + /* + No need to cache the package body itself. + It gets cached during open_and_process_routine() + for the first used package routine. See the package related code + in the "case" below. + */ + if (sp_acquire_mdl(thd, rt, ot_ctx)) + DBUG_RETURN(TRUE); + break; + case MDL_key::FUNCTION: + case MDL_key::PROCEDURE: + { + sp_head *sp; + /* + Try to get MDL lock on the routine. + Note that we do not take locks on top-level CALLs as this can + lead to a deadlock. Not locking top-level CALLs does not break + the binlog as only the statements in the called procedure show + up there, not the CALL itself. + */ + if (rt != (Sroutine_hash_entry*)prelocking_ctx->sroutines_list.first || + mdl_type != MDL_key::PROCEDURE) + { + /* + TODO: If this is a package routine, we should not put MDL + TODO: on the routine itself. We should put only the package MDL. + */ + if (sp_acquire_mdl(thd, rt, ot_ctx)) + DBUG_RETURN(TRUE); + + /* Ensures the routine is up-to-date and cached, if exists. */ + if (rt->sp_cache_routine(thd, has_prelocking_list, &sp)) + DBUG_RETURN(TRUE); + + /* Remember the version of the routine in the parse tree. */ + if (check_and_update_routine_version(thd, rt, sp)) + DBUG_RETURN(TRUE); + + /* 'sp' is NULL when there is no such routine. */ + if (sp) + { + *routine_modifies_data= sp->modifies_data(); + + if (!has_prelocking_list) + { + prelocking_strategy->handle_routine(thd, prelocking_ctx, rt, sp, + need_prelocking); + if (sp->m_parent) + { + /* + If it's a package routine, we need also to handle the + package body, as its initialization section can use + some tables and routine calls. + TODO: Only package public routines actually need this. + TODO: Skip package body handling for private routines. + */ + *routine_modifies_data|= sp->m_parent->modifies_data(); + prelocking_strategy->handle_routine(thd, prelocking_ctx, rt, + sp->m_parent, + need_prelocking); + } + } + } + } + else + { + /* + If it's a top level call, just make sure we have a recent + version of the routine, if it exists. + Validating routine version is unnecessary, since CALL + does not affect the prepared statement prelocked list. + */ + if (rt->sp_cache_routine(thd, false, &sp)) + DBUG_RETURN(TRUE); + } + } + break; + case MDL_key::TRIGGER: + /** + We add trigger entries to lex->sroutines_list, but we don't + load them here. The trigger entry is only used when building + a transitive closure of objects used in a statement, to avoid + adding to this closure objects that are used in the trigger more + than once. + E.g. if a trigger trg refers to table t2, and the trigger table t1 + is used multiple times in the statement (say, because it's used in + function f1() twice), we will only add t2 once to the list of + tables to prelock. + + We don't take metadata locks on triggers either: they are protected + by a respective lock on the table, on which the trigger is defined. + + The only two cases which give "trouble" are SHOW CREATE TRIGGER + and DROP TRIGGER statements. For these, statement syntax doesn't + specify the table on which this trigger is defined, so we have + to make a "dirty" read in the data dictionary to find out the + table name. Once we discover the table name, we take a metadata + lock on it, and this protects all trigger operations. + Of course the table, in theory, may disappear between the dirty + read and metadata lock acquisition, but in that case we just return + a run-time error. + + Grammar of other trigger DDL statements (CREATE, DROP) requires + the table to be specified explicitly, so we use the table metadata + lock to protect trigger metadata in these statements. Similarly, in + DML we always use triggers together with their tables, and thus don't + need to take separate metadata locks on them. + */ + break; + default: + /* Impossible type value. */ + DBUG_ASSERT(0); + } + DBUG_RETURN(FALSE); +} + +/* + If we are not already in prelocked mode and extended table list is not + yet built we might have to build the prelocking set for this statement. + + Since currently no prelocking strategy prescribes doing anything for + tables which are only read, we do below checks only if table is going + to be changed. +*/ +bool extend_table_list(THD *thd, TABLE_LIST *tables, + Prelocking_strategy *prelocking_strategy, + bool has_prelocking_list) +{ + bool error= false; + LEX *lex= thd->lex; + bool maybe_need_prelocking= + (tables->updating && tables->lock_type >= TL_WRITE_ALLOW_WRITE) + || thd->lex->default_used; + + if (thd->locked_tables_mode <= LTM_LOCK_TABLES && + ! has_prelocking_list && maybe_need_prelocking) + { + bool need_prelocking= FALSE; + TABLE_LIST **save_query_tables_last= lex->query_tables_last; + /* + Extend statement's table list and the prelocking set with + tables and routines according to the current prelocking + strategy. + + For example, for DML statements we need to add tables and routines + used by triggers which are going to be invoked for this element of + table list and also add tables required for handling of foreign keys. + */ + error= prelocking_strategy->handle_table(thd, lex, tables, + &need_prelocking); + + if (need_prelocking && ! lex->requires_prelocking()) + lex->mark_as_requiring_prelocking(save_query_tables_last); + } + return error; +} + + +/** + Handle table list element by obtaining metadata lock, opening table or view + and, if prelocking strategy prescribes so, extending the prelocking set with + tables and routines used by it. + + @param[in] thd Thread context. + @param[in] lex LEX structure for statement. + @param[in] tables Table list element to be processed. + @param[in,out] counter Number of tables which are open. + @param[in] flags Bitmap of flags to modify how the tables + will be open, see open_table() description + for details. + @param[in] prelocking_strategy Strategy which specifies how the + prelocking set should be extended + when table or view is processed. + @param[in] has_prelocking_list Indicates that prelocking set/list for + this statement has already been built. + @param[in] ot_ctx Context used to recover from a failed + open_table() attempt. + + @retval FALSE Success. + @retval TRUE Error, reported unless there is a chance to recover from it. +*/ + +static bool +open_and_process_table(THD *thd, TABLE_LIST *tables, uint *counter, uint flags, + Prelocking_strategy *prelocking_strategy, + bool has_prelocking_list, Open_table_context *ot_ctx) +{ + bool error= FALSE; + bool safe_to_ignore_table= FALSE; + LEX *lex= thd->lex; + DBUG_ENTER("open_and_process_table"); + DEBUG_SYNC(thd, "open_and_process_table"); + + /* + Ignore placeholders for derived tables. After derived tables + processing, link to created temporary table will be put here. + If this is derived table for view then we still want to process + routines used by this view. + */ + if (tables->derived) + { + if (!tables->view) + { + if (!tables->is_derived()) + tables->set_derived(); + goto end; + } + /* + We restore view's name and database wiped out by derived tables + processing and fall back to standard open process in order to + obtain proper metadata locks and do other necessary steps like + stored routine processing. + */ + tables->db= tables->view_db; + tables->table_name= tables->view_name; + } + + if (!tables->derived && is_infoschema_db(&tables->db)) + { + /* + Check whether the information schema contains a table + whose name is tables->schema_table_name + */ + ST_SCHEMA_TABLE *schema_table= tables->schema_table; + if (!schema_table || + (schema_table->hidden && + ((sql_command_flags[lex->sql_command] & CF_STATUS_COMMAND) == 0 || + /* + this check is used for show columns|keys from I_S hidden table + */ + lex->sql_command == SQLCOM_SHOW_FIELDS || + lex->sql_command == SQLCOM_SHOW_KEYS))) + { + my_error(ER_UNKNOWN_TABLE, MYF(0), + tables->table_name.str, INFORMATION_SCHEMA_NAME.str); + DBUG_RETURN(1); + } + } + /* + If this TABLE_LIST object is a placeholder for an information_schema + table, create a temporary table to represent the information_schema + table in the query. Do not fill it yet - will be filled during + execution. + */ + if (tables->schema_table) + { + /* + If this information_schema table is merged into a mergeable + view, ignore it for now -- it will be filled when its respective + TABLE_LIST is processed. This code works only during re-execution. + */ + if (tables->view) + { + MDL_ticket *mdl_ticket; + /* + We still need to take a MDL lock on the merged view to protect + it from concurrent changes. + */ + if (!open_table_get_mdl_lock(thd, ot_ctx, &tables->mdl_request, + flags, &mdl_ticket) && + mdl_ticket != NULL) + goto process_view_routines; + /* Fall-through to return error. */ + } + else if (!mysql_schema_table(thd, lex, tables) && + !check_and_update_table_version(thd, tables, tables->table->s)) + { + goto end; + } + error= TRUE; + goto end; + } + DBUG_PRINT("tcache", ("opening table: '%s'.'%s' item: %p", + tables->db.str, tables->table_name.str, tables)); + (*counter)++; + + /* + Not a placeholder: must be a base/temporary table or a view. Let us open it. + */ + if (tables->table) + { + /* + If this TABLE_LIST object has an associated open TABLE object + (TABLE_LIST::table is not NULL), that TABLE object must be a pre-opened + temporary table or SEQUENCE (see sequence_insert()). + */ + DBUG_ASSERT(is_temporary_table(tables) || tables->table->s->sequence); + if (tables->sequence && + tables->table->s->table_type != TABLE_TYPE_SEQUENCE) + { + my_error(ER_NOT_SEQUENCE, MYF(0), tables->db.str, tables->alias.str); + DBUG_RETURN(true); + } + } + else if (tables->open_type == OT_TEMPORARY_ONLY) + { + /* + OT_TEMPORARY_ONLY means that we are in CREATE TEMPORARY TABLE statement. + Also such table list element can't correspond to prelocking placeholder + or to underlying table of merge table. + So existing temporary table should have been preopened by this moment + and we can simply continue without trying to open temporary or base + table. + */ + DBUG_ASSERT(tables->open_strategy); + DBUG_ASSERT(!tables->prelocking_placeholder); + DBUG_ASSERT(!tables->parent_l); + DBUG_RETURN(0); + } + + /* Not a placeholder: must be a base table or a view. Let us open it. */ + if (tables->prelocking_placeholder) + { + /* + For the tables added by the pre-locking code, attempt to open + the table but fail silently if the table does not exist. + The real failure will occur when/if a statement attempts to use + that table. + */ + No_such_table_error_handler no_such_table_handler; + thd->push_internal_handler(&no_such_table_handler); + + /* + We're opening a table from the prelocking list. + + Since this table list element might have been added after pre-opening + of temporary tables we have to try to open temporary table for it. + + We can't simply skip this table list element and postpone opening of + temporary table till the execution of substatement for several reasons: + - Temporary table can be a MERGE table with base underlying tables, + so its underlying tables has to be properly open and locked at + prelocking stage. + - Temporary table can be a MERGE table and we might be in PREPARE + phase for a prepared statement. In this case it is important to call + HA_ATTACH_CHILDREN for all merge children. + This is necessary because merge children remember "TABLE_SHARE ref type" + and "TABLE_SHARE def version" in the HA_ATTACH_CHILDREN operation. + If HA_ATTACH_CHILDREN is not called, these attributes are not set. + Then, during the first EXECUTE, those attributes need to be updated. + That would cause statement re-preparing (because changing those + attributes during EXECUTE is caught by THD::m_reprepare_observers). + The problem is that since those attributes are not set in merge + children, another round of PREPARE will not help. + */ + if (!thd->has_temporary_tables() || + (!(error= thd->open_temporary_table(tables)) && + !tables->table)) + error= open_table(thd, tables, ot_ctx); + + thd->pop_internal_handler(); + safe_to_ignore_table= no_such_table_handler.safely_trapped_errors(); + } + else if (tables->parent_l && (thd->open_options & HA_OPEN_FOR_REPAIR)) + { + /* + Also fail silently for underlying tables of a MERGE table if this + table is opened for CHECK/REPAIR TABLE statement. This is needed + to provide complete list of problematic underlying tables in + CHECK/REPAIR TABLE output. + */ + Repair_mrg_table_error_handler repair_mrg_table_handler; + thd->push_internal_handler(&repair_mrg_table_handler); + + if (!thd->has_temporary_tables() || + (!(error= thd->open_temporary_table(tables)) && + !tables->table)) + error= open_table(thd, tables, ot_ctx); + + thd->pop_internal_handler(); + safe_to_ignore_table= repair_mrg_table_handler.safely_trapped_errors(); + } + else + { + if (tables->parent_l) + { + /* + Even if we are opening table not from the prelocking list we + still might need to look for a temporary table if this table + list element corresponds to underlying table of a merge table. + */ + if (thd->has_temporary_tables()) + error= thd->open_temporary_table(tables); + } + + if (!error && !tables->table) + error= open_table(thd, tables, ot_ctx); + } + + if (unlikely(error)) + { + if (! ot_ctx->can_recover_from_failed_open() && safe_to_ignore_table) + { + DBUG_PRINT("info", ("open_table: ignoring table '%s'.'%s'", + tables->db.str, tables->alias.str)); + error= FALSE; + } + goto end; + } + + /* + We can't rely on simple check for TABLE_LIST::view to determine + that this is a view since during re-execution we might reopen + ordinary table in place of view and thus have TABLE_LIST::view + set from repvious execution and TABLE_LIST::table set from + current. + */ + if (!tables->table && tables->view) + { + /* VIEW placeholder */ + (*counter)--; + + /* + tables->next_global list consists of two parts: + 1) Query tables and underlying tables of views. + 2) Tables used by all stored routines that this statement invokes on + execution. + We need to know where the bound between these two parts is. If we've + just opened a view, which was the last table in part #1, and it + has added its base tables after itself, adjust the boundary pointer + accordingly. + */ + if (lex->query_tables_own_last == &(tables->next_global) && + tables->view->query_tables) + lex->query_tables_own_last= tables->view->query_tables_last; + /* + Let us free memory used by 'sroutines' hash here since we never + call destructor for this LEX. + */ + my_hash_free(&tables->view->sroutines); + goto process_view_routines; + } + + /* + Special types of open can succeed but still don't set + TABLE_LIST::table to anything. + */ + if (tables->open_strategy && !tables->table) + goto end; + + error= extend_table_list(thd, tables, prelocking_strategy, has_prelocking_list); + if (unlikely(error)) + goto end; + + /* Copy grant information from TABLE_LIST instance to TABLE one. */ + tables->table->grant= tables->grant; + + /* Check and update metadata version of a base table. */ + error= check_and_update_table_version(thd, tables, tables->table->s); + + if (unlikely(error)) + goto end; + /* + After opening a MERGE table add the children to the query list of + tables, so that they are opened too. + Note that placeholders don't have the handler open. + */ + /* MERGE tables need to access parent and child TABLE_LISTs. */ + DBUG_ASSERT(tables->table->pos_in_table_list == tables); + /* Non-MERGE tables ignore this call. */ + if (tables->table->file->extra(HA_EXTRA_ADD_CHILDREN_LIST)) + { + error= TRUE; + goto end; + } + +process_view_routines: + /* + Again we may need cache all routines used by this view and add + tables used by them to table list. + */ + if (tables->view && + thd->locked_tables_mode <= LTM_LOCK_TABLES && + ! has_prelocking_list) + { + bool need_prelocking= FALSE; + TABLE_LIST **save_query_tables_last= lex->query_tables_last; + + error= prelocking_strategy->handle_view(thd, lex, tables, + &need_prelocking); + + if (need_prelocking && ! lex->requires_prelocking()) + lex->mark_as_requiring_prelocking(save_query_tables_last); + + if (unlikely(error)) + goto end; + } + +end: + DBUG_RETURN(error); +} + + +static bool upgrade_lock_if_not_exists(THD *thd, + const DDL_options_st &create_info, + TABLE_LIST *create_table, + ulong lock_wait_timeout) +{ + DBUG_ENTER("upgrade_lock_if_not_exists"); + + if (thd->lex->sql_command == SQLCOM_CREATE_TABLE || + thd->lex->sql_command == SQLCOM_CREATE_SEQUENCE) + { + DEBUG_SYNC(thd,"create_table_before_check_if_exists"); + if (!create_info.or_replace() && + ha_table_exists(thd, &create_table->db, &create_table->table_name, + &create_table->db_type)) + { + if (create_info.if_not_exists()) + { + push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE, + ER_TABLE_EXISTS_ERROR, + ER_THD(thd, ER_TABLE_EXISTS_ERROR), + create_table->table_name.str); + } + else + my_error(ER_TABLE_EXISTS_ERROR, MYF(0), create_table->table_name.str); + DBUG_RETURN(true); + } + DBUG_RETURN(thd->mdl_context.upgrade_shared_lock( + create_table->mdl_request.ticket, + MDL_EXCLUSIVE, + lock_wait_timeout)); + } + DBUG_RETURN(false); +} + + +/** + Acquire upgradable (SNW, SNRW) metadata locks on tables used by + LOCK TABLES or by a DDL statement. Under LOCK TABLES, we can't take + new locks, so use open_tables_check_upgradable_mdl() instead. + + @param thd Thread context. + @param options DDL options. + @param tables_start Start of list of tables on which upgradable locks + should be acquired. + @param tables_end End of list of tables. + @param lock_wait_timeout Seconds to wait before timeout. + @param flags Bitmap of flags to modify how the tables will be + open, see open_table() description for details. + + @retval FALSE Success. + @retval TRUE Failure (e.g. connection was killed) or table existed + for a CREATE TABLE. + + @notes + In case of CREATE TABLE we avoid a wait for tables that are in use + by first trying to do a meta data lock with timeout == 0. If we get a + timeout we will check if table exists (it should) and retry with + normal timeout if it didn't exists. + Note that for CREATE TABLE IF EXISTS we only generate a warning + but still return TRUE (to abort the calling open_table() function). + On must check THD->is_error() if one wants to distinguish between warning + and error. If table existed, tables_start->db_type is set to the handlerton + for the found table. +*/ + +bool +lock_table_names(THD *thd, const DDL_options_st &options, + TABLE_LIST *tables_start, TABLE_LIST *tables_end, + ulong lock_wait_timeout, uint flags) +{ + MDL_request_list mdl_requests; + TABLE_LIST *table; + MDL_request global_request; + MDL_savepoint mdl_savepoint; + DBUG_ENTER("lock_table_names"); + + DBUG_ASSERT(!thd->locked_tables_mode); + + for (table= tables_start; table && table != tables_end; + table= table->next_global) + { + DBUG_PRINT("info", ("mdl_request.type: %d open_type: %d", + table->mdl_request.type, table->open_type)); + if (table->mdl_request.type < MDL_SHARED_UPGRADABLE || + table->mdl_request.type == MDL_SHARED_READ_ONLY || + table->open_type == OT_TEMPORARY_ONLY || + (table->open_type == OT_TEMPORARY_OR_BASE && is_temporary_table(table))) + { + continue; + } + + /* Write lock on normal tables is not allowed in a read only transaction. */ + if (thd->tx_read_only) + { + my_error(ER_CANT_EXECUTE_IN_READ_ONLY_TRANSACTION, MYF(0)); + DBUG_RETURN(true); + } + + /* Scoped locks: Take intention exclusive locks on all involved schemas. */ + if (!(flags & MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK)) + { + MDL_request *schema_request= new (thd->mem_root) MDL_request; + if (schema_request == NULL) + DBUG_RETURN(TRUE); + MDL_REQUEST_INIT(schema_request, MDL_key::SCHEMA, table->db.str, "", + MDL_INTENTION_EXCLUSIVE, MDL_TRANSACTION); + mdl_requests.push_front(schema_request); + } + + mdl_requests.push_front(&table->mdl_request); + } + + if (mdl_requests.is_empty()) + DBUG_RETURN(FALSE); + + if (flags & MYSQL_OPEN_SKIP_SCOPED_MDL_LOCK) + { + DBUG_RETURN(thd->mdl_context.acquire_locks(&mdl_requests, + lock_wait_timeout) || + upgrade_lock_if_not_exists(thd, options, tables_start, + lock_wait_timeout)); + } + + /* Protect this statement against concurrent BACKUP STAGE or FTWRL. */ + if (thd->has_read_only_protection()) + DBUG_RETURN(true); + + MDL_REQUEST_INIT(&global_request, MDL_key::BACKUP, "", "", MDL_BACKUP_DDL, + MDL_STATEMENT); + mdl_savepoint= thd->mdl_context.mdl_savepoint(); + + while (!thd->mdl_context.acquire_locks(&mdl_requests, lock_wait_timeout) && + !upgrade_lock_if_not_exists(thd, options, tables_start, + lock_wait_timeout) && + !thd->mdl_context.try_acquire_lock(&global_request)) + { + if (global_request.ticket) + { + thd->mdl_backup_ticket= global_request.ticket; + DBUG_RETURN(false); + } + + /* + There is ongoing or pending BACKUP STAGE or FTWRL. + Wait until it finishes and re-try. + */ + thd->mdl_context.rollback_to_savepoint(mdl_savepoint); + if (thd->mdl_context.acquire_lock(&global_request, lock_wait_timeout)) + break; + thd->mdl_context.rollback_to_savepoint(mdl_savepoint); + + /* Reset tickets for all acquired locks */ + global_request.ticket= 0; + MDL_request_list::Iterator it(mdl_requests); + while (auto mdl_request= it++) + mdl_request->ticket= 0; + } + DBUG_RETURN(true); +} + + +/** + Check for upgradable (SNW, SNRW) metadata locks on tables to be opened + for a DDL statement. Under LOCK TABLES, we can't take new locks, so we + must check if appropriate locks were pre-acquired. + + @param thd Thread context. + @param tables_start Start of list of tables on which upgradable locks + should be searched for. + @param tables_end End of list of tables. + @param flags Bitmap of flags to modify how the tables will be + open, see open_table() description for details. + + @retval FALSE Success. + @retval TRUE Failure (e.g. connection was killed) +*/ + +static bool +open_tables_check_upgradable_mdl(THD *thd, TABLE_LIST *tables_start, + TABLE_LIST *tables_end, uint flags) +{ + TABLE_LIST *table; + + DBUG_ASSERT(thd->locked_tables_mode); + + for (table= tables_start; table && table != tables_end; + table= table->next_global) + { + /* + Check below needs to be updated if this function starts + called for SRO locks. + */ + DBUG_ASSERT(table->mdl_request.type != MDL_SHARED_READ_ONLY); + if (table->mdl_request.type < MDL_SHARED_UPGRADABLE || + table->open_type == OT_TEMPORARY_ONLY || + (table->open_type == OT_TEMPORARY_OR_BASE && is_temporary_table(table))) + { + continue; + } + + /* + We don't need to do anything about the found TABLE instance as it + will be handled later in open_tables(), we only need to check that + an upgradable lock is already acquired. When we enter LOCK TABLES + mode, SNRW locks are acquired before all other locks. So if under + LOCK TABLES we find that there is TABLE instance with upgradeable + lock, all other instances of TABLE for the same table will have the + same ticket. + + Note that this works OK even for CREATE TABLE statements which + request X type of metadata lock. This is because under LOCK TABLES + such statements don't create the table but only check if it exists + or, in most complex case, only insert into it. + Thus SNRW lock should be enough. + + Note that find_table_for_mdl_upgrade() will report an error if + no suitable ticket is found. + */ + if (!find_table_for_mdl_upgrade(thd, table->db.str, table->table_name.str, + NULL)) + return TRUE; + } + + return FALSE; +} + + +/** + Open all tables in list + + @param[in] thd Thread context. + @param[in] options DDL options. + @param[in,out] start List of tables to be open (it can be adjusted for + statement that uses tables only implicitly, e.g. + for "SELECT f1()"). + @param[out] counter Number of tables which were open. + @param[in] flags Bitmap of flags to modify how the tables will be + open, see open_table() description for details. + @param[in] prelocking_strategy Strategy which specifies how prelocking + algorithm should work for this statement. + + @note + Unless we are already in prelocked mode and prelocking strategy prescribes + so this function will also precache all SP/SFs explicitly or implicitly + (via views and triggers) used by the query and add tables needed for their + execution to table list. Statement that uses SFs, invokes triggers or + requires foreign key checks will be marked as requiring prelocking. + Prelocked mode will be enabled for such query during lock_tables() call. + + If query for which we are opening tables is already marked as requiring + prelocking it won't do such precaching and will simply reuse table list + which is already built. + + @retval FALSE Success. + @retval TRUE Error, reported. +*/ + +bool open_tables(THD *thd, const DDL_options_st &options, + TABLE_LIST **start, uint *counter, uint flags, + Prelocking_strategy *prelocking_strategy) +{ + /* + We use pointers to "next_global" member in the last processed + TABLE_LIST element and to the "next" member in the last processed + Sroutine_hash_entry element as iterators over, correspondingly, + the table list and stored routines list which stay valid and allow + to continue iteration when new elements are added to the tail of + the lists. + */ + TABLE_LIST **table_to_open; + Sroutine_hash_entry **sroutine_to_open; + TABLE_LIST *tables; + Open_table_context ot_ctx(thd, flags); + bool error= FALSE; + bool some_routine_modifies_data= FALSE; + bool has_prelocking_list; + DBUG_ENTER("open_tables"); + + /* Data access in XA transaction is only allowed when it is active. */ + for (TABLE_LIST *table= *start; table; table= table->next_global) + if (!table->schema_table) + { + if (thd->transaction->xid_state.check_has_uncommitted_xa()) + { + thd->transaction->xid_state.er_xaer_rmfail(); + DBUG_RETURN(true); + } + else + break; + } + + thd->current_tablenr= 0; +restart: + /* + Close HANDLER tables which are marked for flush or against which there + are pending exclusive metadata locks. This is needed both in order to + avoid deadlocks and to have a point during statement execution at + which such HANDLERs are closed even if they don't create problems for + the current session (i.e. to avoid having a DDL blocked by HANDLERs + opened for a long time). + */ + if (thd->handler_tables_hash.records) + mysql_ha_flush(thd); + + has_prelocking_list= thd->lex->requires_prelocking(); + table_to_open= start; + sroutine_to_open= &thd->lex->sroutines_list.first; + *counter= 0; + THD_STAGE_INFO(thd, stage_opening_tables); + prelocking_strategy->reset(thd); + + /* + If we are executing LOCK TABLES statement or a DDL statement + (in non-LOCK TABLES mode) we might have to acquire upgradable + semi-exclusive metadata locks (SNW or SNRW) on some of the + tables to be opened. + When executing CREATE TABLE .. If NOT EXISTS .. SELECT, the + table may not yet exist, in which case we acquire an exclusive + lock. + We acquire all such locks at once here as doing this in one + by one fashion may lead to deadlocks or starvation. Later when + we will be opening corresponding table pre-acquired metadata + lock will be reused (thanks to the fact that in recursive case + metadata locks are acquired without waiting). + */ + if (! (flags & (MYSQL_OPEN_HAS_MDL_LOCK | + MYSQL_OPEN_FORCE_SHARED_MDL | + MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL))) + { + if (thd->locked_tables_mode) + { + /* + Under LOCK TABLES, we can't acquire new locks, so we instead + need to check if appropriate locks were pre-acquired. + */ + if (open_tables_check_upgradable_mdl(thd, *start, + thd->lex->first_not_own_table(), + flags)) + { + error= TRUE; + goto error; + } + } + else + { + TABLE_LIST *table; + if (lock_table_names(thd, options, *start, + thd->lex->first_not_own_table(), + ot_ctx.get_timeout(), flags)) + { + error= TRUE; + goto error; + } + for (table= *start; table && table != thd->lex->first_not_own_table(); + table= table->next_global) + { + if (table->mdl_request.type >= MDL_SHARED_UPGRADABLE) + table->mdl_request.ticket= NULL; + } + } + } + + /* + Perform steps of prelocking algorithm until there are unprocessed + elements in prelocking list/set. + */ + while (*table_to_open || + (thd->locked_tables_mode <= LTM_LOCK_TABLES && *sroutine_to_open)) + { + /* + For every table in the list of tables to open, try to find or open + a table. + */ + for (tables= *table_to_open; tables; + table_to_open= &tables->next_global, tables= tables->next_global) + { + error= open_and_process_table(thd, tables, counter, flags, + prelocking_strategy, has_prelocking_list, + &ot_ctx); + + if (unlikely(error)) + { + if (ot_ctx.can_recover_from_failed_open()) + { + /* + We have met exclusive metadata lock or old version of table. + Now we have to close all tables and release metadata locks. + We also have to throw away set of prelocked tables (and thus + close tables from this set that were open by now) since it + is possible that one of tables which determined its content + was changed. + + Instead of implementing complex/non-robust logic mentioned + above we simply close and then reopen all tables. + + We have to save pointer to table list element for table which we + have failed to open since closing tables can trigger removal of + elements from the table list (if MERGE tables are involved), + */ + close_tables_for_reopen(thd, start, ot_ctx.start_of_statement_svp()); + + /* + Here we rely on the fact that 'tables' still points to the valid + TABLE_LIST element. Altough currently this assumption is valid + it may change in future. + */ + if (ot_ctx.recover_from_failed_open()) + goto error; + + /* Re-open temporary tables after close_tables_for_reopen(). */ + if (thd->open_temporary_tables(*start)) + goto error; + + error= FALSE; + goto restart; + } + goto error; + } + + DEBUG_SYNC(thd, "open_tables_after_open_and_process_table"); + } + + /* + If we are not already in prelocked mode and extended table list is + not yet built for our statement we need to cache routines it uses + and build the prelocking list for it. + If we are not in prelocked mode but have built the extended table + list, we still need to call open_and_process_routine() to take + MDL locks on the routines. + */ + if (thd->locked_tables_mode <= LTM_LOCK_TABLES && *sroutine_to_open) + { + /* + Process elements of the prelocking set which are present there + since parsing stage or were added to it by invocations of + Prelocking_strategy methods in the above loop over tables. + + For example, if element is a routine, cache it and then, + if prelocking strategy prescribes so, add tables it uses to the + table list and routines it might invoke to the prelocking set. + */ + for (Sroutine_hash_entry *rt= *sroutine_to_open; rt; + sroutine_to_open= &rt->next, rt= rt->next) + { + bool need_prelocking= false; + bool routine_modifies_data; + TABLE_LIST **save_query_tables_last= thd->lex->query_tables_last; + + error= open_and_process_routine(thd, thd->lex, rt, prelocking_strategy, + has_prelocking_list, &ot_ctx, + &need_prelocking, + &routine_modifies_data); + + // Remember if any of SF modifies data. + some_routine_modifies_data|= routine_modifies_data; + + if (need_prelocking && ! thd->lex->requires_prelocking()) + thd->lex->mark_as_requiring_prelocking(save_query_tables_last); + + if (need_prelocking && ! *start) + *start= thd->lex->query_tables; + + if (unlikely(error)) + { + if (ot_ctx.can_recover_from_failed_open()) + { + close_tables_for_reopen(thd, start, + ot_ctx.start_of_statement_svp()); + if (ot_ctx.recover_from_failed_open()) + goto error; + + /* Re-open temporary tables after close_tables_for_reopen(). */ + if (thd->open_temporary_tables(*start)) + goto error; + + error= FALSE; + goto restart; + } + /* + Serious error during reading stored routines from mysql.proc table. + Something is wrong with the table or its contents, and an error has + been emitted; we must abort. + */ + goto error; + } + } + } + if ((error= prelocking_strategy->handle_end(thd))) + goto error; + } + + /* + After successful open of all tables, including MERGE parents and + children, attach the children to their parents. At end of statement, + the children are detached. Attaching and detaching are always done, + even under LOCK TABLES. + + We also convert all TL_WRITE_DEFAULT and TL_READ_DEFAULT locks to + appropriate "real" lock types to be used for locking and to be passed + to storage engine. + + And start wsrep TOI if needed. + */ + for (tables= *start; tables; tables= tables->next_global) + { + TABLE *tbl= tables->table; + + if (!tbl) + continue; + + /* Schema tables may not have a TABLE object here. */ + if (tbl->file->ha_table_flags() & HA_CAN_MULTISTEP_MERGE) + { + /* MERGE tables need to access parent and child TABLE_LISTs. */ + DBUG_ASSERT(tbl->pos_in_table_list == tables); + if (tbl->file->extra(HA_EXTRA_ATTACH_CHILDREN)) + { + error= TRUE; + goto error; + } + } + + /* Set appropriate TABLE::lock_type. */ + if (tbl && tables->lock_type != TL_UNLOCK && !thd->locked_tables_mode) + { + if (tables->lock_type == TL_WRITE_DEFAULT) + tbl->reginfo.lock_type= thd->update_lock_default; + else if (tables->lock_type == TL_READ_DEFAULT) + tbl->reginfo.lock_type= + read_lock_type_for_table(thd, thd->lex, tables, + some_routine_modifies_data); + else + tbl->reginfo.lock_type= tables->lock_type; + } + } + +#ifdef WITH_WSREP + if (WSREP(thd) && + wsrep_replicate_myisam && + (*start) && + (*start)->table && + (*start)->table->file->ht == myisam_hton && + wsrep_thd_is_local(thd) && + !is_stat_table(&(*start)->db, &(*start)->alias) && + thd->get_command() != COM_STMT_PREPARE && + ((thd->lex->sql_command == SQLCOM_INSERT || + thd->lex->sql_command == SQLCOM_INSERT_SELECT || + thd->lex->sql_command == SQLCOM_REPLACE || + thd->lex->sql_command == SQLCOM_REPLACE_SELECT || + thd->lex->sql_command == SQLCOM_UPDATE || + thd->lex->sql_command == SQLCOM_UPDATE_MULTI || + thd->lex->sql_command == SQLCOM_LOAD || + thd->lex->sql_command == SQLCOM_DELETE))) + { + wsrep_before_rollback(thd, true); + wsrep_after_rollback(thd, true); + wsrep_after_statement(thd); + WSREP_TO_ISOLATION_BEGIN(NULL, NULL, (*start)); + } +#endif /* WITH_WSREP */ + +error: +#ifdef WITH_WSREP +wsrep_error_label: +#endif + THD_STAGE_INFO(thd, stage_after_opening_tables); + thd_proc_info(thd, 0); + + if (unlikely(error) && *table_to_open) + { + (*table_to_open)->table= NULL; + } + DBUG_PRINT("open_tables", ("returning: %d", (int) error)); + DBUG_RETURN(error); +} + + +/** + Defines how prelocking algorithm for DML statements should handle routines: + - For CALL statements we do unrolling (i.e. open and lock tables for each + sub-statement individually). So for such statements prelocking is enabled + only if stored functions are used in parameter list and only for period + during which we calculate values of parameters. Thus in this strategy we + ignore procedure which is directly called by such statement and extend + the prelocking set only with tables/functions used by SF called from the + parameter list. + - For any other statement any routine which is directly or indirectly called + by statement is going to be executed in prelocked mode. So in this case we + simply add all tables and routines used by it to the prelocking set. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context of the statement. + @param[in] rt Prelocking set element describing routine. + @param[in] sp Routine body. + @param[out] need_prelocking Set to TRUE if method detects that prelocking + required, not changed otherwise. + + @retval FALSE Success. + @retval TRUE Failure (OOM). +*/ + +bool DML_prelocking_strategy:: +handle_routine(THD *thd, Query_tables_list *prelocking_ctx, + Sroutine_hash_entry *rt, sp_head *sp, bool *need_prelocking) +{ + /* + We assume that for any "CALL proc(...)" statement sroutines_list will + have 'proc' as first element (it may have several, consider e.g. + "proc(sp_func(...)))". This property is currently guaranted by the + parser. + */ + + if (rt != (Sroutine_hash_entry*)prelocking_ctx->sroutines_list.first || + rt->mdl_request.key.mdl_namespace() != MDL_key::PROCEDURE) + { + *need_prelocking= TRUE; + sp_update_stmt_used_routines(thd, prelocking_ctx, &sp->m_sroutines, + rt->belong_to_view); + (void)sp->add_used_tables_to_table_list(thd, + &prelocking_ctx->query_tables_last, + rt->belong_to_view); + } + sp->propagate_attributes(prelocking_ctx); + return FALSE; +} + + +/* + @note this can be changed to use a hash, instead of scanning the linked + list, if the performance of this function will ever become an issue +*/ +bool table_already_fk_prelocked(TABLE_LIST *tl, LEX_CSTRING *db, + LEX_CSTRING *table, thr_lock_type lock_type) +{ + for (; tl; tl= tl->next_global ) + { + if (tl->lock_type >= lock_type && + tl->prelocking_placeholder == TABLE_LIST::PRELOCK_FK && + strcmp(tl->db.str, db->str) == 0 && + strcmp(tl->table_name.str, table->str) == 0) + return true; + } + return false; +} + + +static bool internal_table_exists(TABLE_LIST *global_list, + const char *table_name) +{ + do + { + if (global_list->table_name.str == table_name) + return 1; + } while ((global_list= global_list->next_global)); + return 0; +} + + +static bool +add_internal_tables(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *tables) +{ + TABLE_LIST *global_table_list= prelocking_ctx->query_tables; + DBUG_ENTER("add_internal_tables"); + + do + { + DBUG_PRINT("info", ("table name: %s", tables->table_name.str)); + /* + Skip table if already in the list. Can happen with prepared statements + */ + if (tables->next_local && + internal_table_exists(global_table_list, tables->table_name.str)) + continue; + + TABLE_LIST *tl= (TABLE_LIST *) thd->alloc(sizeof(TABLE_LIST)); + if (!tl) + DBUG_RETURN(TRUE); + tl->init_one_table_for_prelocking(&tables->db, + &tables->table_name, + NULL, tables->lock_type, + TABLE_LIST::PRELOCK_NONE, + 0, 0, + &prelocking_ctx->query_tables_last, + tables->for_insert_data); + /* + Store link to the new table_list that will be used by open so that + Item_func_nextval() can find it + */ + tables->next_local= tl; + DBUG_PRINT("info", ("table name: %s added", tables->table_name.str)); + } while ((tables= tables->next_global)); + DBUG_RETURN(FALSE); +} + +/** + Extend the table_list to include foreign tables for prelocking. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context of the statement. + @param[in] table_list Table list element for table. + @param[in] sp Routine body. + @param[out] need_prelocking Set to TRUE if method detects that prelocking + required, not changed otherwise. + + @retval FALSE Success. + @retval TRUE Failure (OOM). +*/ +inline bool +prepare_fk_prelocking_list(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, bool *need_prelocking, + uint8 op) +{ + DBUG_ENTER("prepare_fk_prelocking_list"); + List <FOREIGN_KEY_INFO> fk_list; + List_iterator<FOREIGN_KEY_INFO> fk_list_it(fk_list); + FOREIGN_KEY_INFO *fk; + Query_arena *arena, backup; + TABLE *table= table_list->table; + + arena= thd->activate_stmt_arena_if_needed(&backup); + + table->file->get_parent_foreign_key_list(thd, &fk_list); + if (unlikely(thd->is_error())) + { + if (arena) + thd->restore_active_arena(arena, &backup); + return TRUE; + } + + *need_prelocking= TRUE; + + while ((fk= fk_list_it++)) + { + // FK_OPTION_RESTRICT and FK_OPTION_NO_ACTION only need read access + thr_lock_type lock_type; + + if ((op & (1 << TRG_EVENT_DELETE) && fk_modifies_child(fk->delete_method)) + || (op & (1 << TRG_EVENT_UPDATE) && fk_modifies_child(fk->update_method))) + lock_type= TL_WRITE_ALLOW_WRITE; + else + lock_type= TL_READ; + + if (table_already_fk_prelocked(prelocking_ctx->query_tables, + fk->foreign_db, fk->foreign_table, + lock_type)) + continue; + + TABLE_LIST *tl= (TABLE_LIST *) thd->alloc(sizeof(TABLE_LIST)); + tl->init_one_table_for_prelocking(fk->foreign_db, + fk->foreign_table, + NULL, lock_type, + TABLE_LIST::PRELOCK_FK, + table_list->belong_to_view, op, + &prelocking_ctx->query_tables_last, + table_list->for_insert_data); + } + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(FALSE); +} + +/** + Defines how prelocking algorithm for DML statements should handle table list + elements: + - If table has triggers we should add all tables and routines + used by them to the prelocking set. + + We do not need to acquire metadata locks on trigger names + in DML statements, since all DDL statements + that change trigger metadata always lock their + subject tables. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context of the statement. + @param[in] table_list Table list element for table. + @param[in] sp Routine body. + @param[out] need_prelocking Set to TRUE if method detects that prelocking + required, not changed otherwise. + + @retval FALSE Success. + @retval TRUE Failure (OOM). +*/ + +bool DML_prelocking_strategy:: +handle_table(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, bool *need_prelocking) +{ + DBUG_ENTER("handle_table"); + TABLE *table= table_list->table; + /* We rely on a caller to check that table is going to be changed. */ + DBUG_ASSERT(table_list->lock_type >= TL_WRITE_ALLOW_WRITE || + thd->lex->default_used); + + if (table_list->trg_event_map) + { + if (table->triggers) + { + *need_prelocking= TRUE; + + if (table->triggers-> + add_tables_and_routines_for_triggers(thd, prelocking_ctx, table_list)) + return TRUE; + } + + if (table->file->referenced_by_foreign_key()) + { + if (prepare_fk_prelocking_list(thd, prelocking_ctx, table_list, + need_prelocking, + table_list->trg_event_map)) + return TRUE; + } + } + else if (table_list->slave_fk_event_map && + table->file->referenced_by_foreign_key()) + { + if (prepare_fk_prelocking_list(thd, prelocking_ctx, table_list, + need_prelocking, + table_list->slave_fk_event_map)) + return TRUE; + } + + /* Open any tables used by DEFAULT (like sequence tables) */ + DBUG_PRINT("info", ("table: %p name: %s db: %s flags: %u", + table_list, table_list->table_name.str, + table_list->db.str, table_list->for_insert_data)); + if (table->internal_tables && + (table_list->for_insert_data || + thd->lex->default_used)) + { + Query_arena *arena, backup; + bool error; + arena= thd->activate_stmt_arena_if_needed(&backup); + error= add_internal_tables(thd, prelocking_ctx, + table->internal_tables); + if (arena) + thd->restore_active_arena(arena, &backup); + if (unlikely(error)) + { + *need_prelocking= TRUE; + DBUG_RETURN(TRUE); + } + } + DBUG_RETURN(FALSE); +} + + +/** + Open all tables used by DEFAULT functions. + + This is different from normal open_and_lock_tables() as we may + already have other tables opened and locked and we have to merge the + new table with the old ones. +*/ + +bool open_and_lock_internal_tables(TABLE *table, bool lock_table) +{ + THD *thd= table->in_use; + TABLE_LIST *tl; + MYSQL_LOCK *save_lock,*new_lock; + DBUG_ENTER("open_and_lock_internal_tables"); + + /* remove pointer to old select_lex which is already destroyed */ + for (tl= table->internal_tables ; tl ; tl= tl->next_global) + tl->select_lex= 0; + + uint counter; + MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint(); + TABLE_LIST *tmp= table->internal_tables; + DML_prelocking_strategy prelocking_strategy; + + if (open_tables(thd, thd->lex->create_info, &tmp, &counter, 0, + &prelocking_strategy)) + goto err; + + if (lock_table) + { + save_lock= thd->lock; + thd->lock= 0; + if (lock_tables(thd, table->internal_tables, counter, + MYSQL_LOCK_USE_MALLOC)) + goto err; + + if (!(new_lock= mysql_lock_merge(save_lock, thd->lock))) + { + thd->lock= save_lock; + mysql_unlock_tables(thd, save_lock, 1); + /* We don't have to close tables as caller will do that */ + goto err; + } + thd->lock= new_lock; + } + DBUG_RETURN(0); + +err: + thd->mdl_context.rollback_to_savepoint(mdl_savepoint); + DBUG_RETURN(1); +} + + +/** + Defines how prelocking algorithm for DML statements should handle view - + all view routines should be added to the prelocking set. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context of the statement. + @param[in] table_list Table list element for view. + @param[in] sp Routine body. + @param[out] need_prelocking Set to TRUE if method detects that prelocking + required, not changed otherwise. + + @retval FALSE Success. + @retval TRUE Failure (OOM). +*/ + +bool DML_prelocking_strategy:: +handle_view(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, bool *need_prelocking) +{ + if (table_list->view->uses_stored_routines()) + { + *need_prelocking= TRUE; + + sp_update_stmt_used_routines(thd, prelocking_ctx, + &table_list->view->sroutines_list, + table_list->top_table()); + } + + /* + If a trigger was defined on one of the associated tables then assign the + 'trg_event_map' value of the view to the next table in table_list. When a + Stored function is invoked, all the associated tables including the tables + associated with the trigger are prelocked. + */ + if (table_list->trg_event_map && table_list->next_global) + table_list->next_global->trg_event_map= table_list->trg_event_map; + return FALSE; +} + + +/** + Defines how prelocking algorithm for LOCK TABLES statement should handle + table list elements. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context of the statement. + @param[in] table_list Table list element for table. + @param[in] sp Routine body. + @param[out] need_prelocking Set to TRUE if method detects that prelocking + required, not changed otherwise. + + @retval FALSE Success. + @retval TRUE Failure (OOM). +*/ + +bool Lock_tables_prelocking_strategy:: +handle_table(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, bool *need_prelocking) +{ + TABLE_LIST **last= prelocking_ctx->query_tables_last; + + if (DML_prelocking_strategy::handle_table(thd, prelocking_ctx, table_list, + need_prelocking)) + return TRUE; + + /* + normally we don't need to open FK-prelocked tables for RESTRICT, + MDL is enough. But under LOCK TABLES we have to open everything + */ + for (TABLE_LIST *tl= *last; tl; tl= tl->next_global) + tl->open_strategy= TABLE_LIST::OPEN_NORMAL; + + /* We rely on a caller to check that table is going to be changed. */ + DBUG_ASSERT(table_list->lock_type >= TL_WRITE_ALLOW_WRITE); + + return FALSE; +} + + +/** + Defines how prelocking algorithm for ALTER TABLE statement should handle + routines - do nothing as this statement is not supposed to call routines. + + We still can end up in this method when someone tries + to define a foreign key referencing a view, and not just + a simple view, but one that uses stored routines. +*/ + +bool Alter_table_prelocking_strategy:: +handle_routine(THD *thd, Query_tables_list *prelocking_ctx, + Sroutine_hash_entry *rt, sp_head *sp, bool *need_prelocking) +{ + return FALSE; +} + + +/** + Defines how prelocking algorithm for ALTER TABLE statement should handle + table list elements. + + Unlike in DML, we do not process triggers here. + + @param[in] thd Thread context. + @param[in] prelocking_ctx Prelocking context of the statement. + @param[in] table_list Table list element for table. + @param[in] sp Routine body. + @param[out] need_prelocking Set to TRUE if method detects that prelocking + required, not changed otherwise. + + + @retval FALSE Success. + @retval TRUE Failure (OOM). +*/ + +bool Alter_table_prelocking_strategy:: +handle_table(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, bool *need_prelocking) +{ + return FALSE; +} + + +/** + Defines how prelocking algorithm for ALTER TABLE statement + should handle view - do nothing. We don't need to add view + routines to the prelocking set in this case as view is not going + to be materialized. +*/ + +bool Alter_table_prelocking_strategy:: +handle_view(THD *thd, Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list, bool *need_prelocking) +{ + return FALSE; +} + + +/** + Check that lock is ok for tables; Call start stmt if ok + + @param thd Thread handle. + @param prelocking_ctx Prelocking context. + @param table_list Table list element for table to be checked. + + @retval FALSE - Ok. + @retval TRUE - Error. +*/ + +static bool check_lock_and_start_stmt(THD *thd, + Query_tables_list *prelocking_ctx, + TABLE_LIST *table_list) +{ + int error; + thr_lock_type lock_type; + DBUG_ENTER("check_lock_and_start_stmt"); + + /* + Prelocking placeholder is not set for TABLE_LIST that + are directly used by TOP level statement. + */ + DBUG_ASSERT(table_list->prelocking_placeholder == TABLE_LIST::PRELOCK_NONE); + + /* + TL_WRITE_DEFAULT and TL_READ_DEFAULT are supposed to be parser only + types of locks so they should be converted to appropriate other types + to be passed to storage engine. The exact lock type passed to the + engine is important as, for example, InnoDB uses it to determine + what kind of row locks should be acquired when executing statement + in prelocked mode or under LOCK TABLES with @@innodb_table_locks = 0. + + Last argument routine_modifies_data for read_lock_type_for_table() + is ignored, as prelocking placeholder will never be set here. + */ + if (table_list->lock_type == TL_WRITE_DEFAULT) + lock_type= thd->update_lock_default; + else if (table_list->lock_type == TL_READ_DEFAULT) + lock_type= read_lock_type_for_table(thd, prelocking_ctx, table_list, true); + else + lock_type= table_list->lock_type; + + if ((int) lock_type >= (int) TL_WRITE_ALLOW_WRITE && + (int) table_list->table->reginfo.lock_type < (int) TL_WRITE_ALLOW_WRITE) + { + my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE, MYF(0), + table_list->table->alias.c_ptr()); + DBUG_RETURN(1); + } + if (unlikely((error= table_list->table->file->start_stmt(thd, lock_type)))) + { + table_list->table->file->print_error(error, MYF(0)); + DBUG_RETURN(1); + } + + /* + Record in transaction state tracking + */ + TRANSACT_TRACKER(add_trx_state(thd, lock_type, + table_list->table->file->has_transactions())); + + DBUG_RETURN(0); +} + + +/** + @brief Open and lock one table + + @param[in] thd thread handle + @param[in] table_l table to open is first table in this list + @param[in] lock_type lock to use for table + @param[in] flags options to be used while opening and locking + table (see open_table(), mysql_lock_tables()) + @param[in] prelocking_strategy Strategy which specifies how prelocking + algorithm should work for this statement. + + @return table + @retval != NULL OK, opened table returned + @retval NULL Error + + @note + If ok, the following are also set: + table_list->lock_type lock_type + table_list->table table + + @note + If table_l is a list, not a single table, the list is temporarily + broken. + + @detail + This function is meant as a replacement for open_ltable() when + MERGE tables can be opened. open_ltable() cannot open MERGE tables. + + There may be more differences between open_n_lock_single_table() and + open_ltable(). One known difference is that open_ltable() does + neither call thd->decide_logging_format() nor handle some other logging + and locking issues because it does not call lock_tables(). +*/ + +TABLE *open_n_lock_single_table(THD *thd, TABLE_LIST *table_l, + thr_lock_type lock_type, uint flags, + Prelocking_strategy *prelocking_strategy) +{ + TABLE_LIST *save_next_global; + DBUG_ENTER("open_n_lock_single_table"); + + /* Remember old 'next' pointer. */ + save_next_global= table_l->next_global; + /* Break list. */ + table_l->next_global= NULL; + + /* Set requested lock type. */ + table_l->lock_type= lock_type; + /* Allow to open real tables only. */ + table_l->required_type= TABLE_TYPE_NORMAL; + + /* Open the table. */ + if (open_and_lock_tables(thd, table_l, FALSE, flags, + prelocking_strategy)) + table_l->table= NULL; /* Just to be sure. */ + + /* Restore list. */ + table_l->next_global= save_next_global; + + DBUG_RETURN(table_l->table); +} + + +/* + Open and lock one table + + SYNOPSIS + open_ltable() + thd Thread handler + table_list Table to open is first table in this list + lock_type Lock to use for open + lock_flags Flags passed to mysql_lock_table + + NOTE + This function doesn't do anything like SP/SF/views/triggers analysis done + in open_table()/lock_tables(). It is intended for opening of only one + concrete table. And used only in special contexts. + + RETURN VALUES + table Opened table + 0 Error + + If ok, the following are also set: + table_list->lock_type lock_type + table_list->table table +*/ + +TABLE *open_ltable(THD *thd, TABLE_LIST *table_list, thr_lock_type lock_type, + uint lock_flags) +{ + TABLE *table; + Open_table_context ot_ctx(thd, lock_flags); + bool error; + DBUG_ENTER("open_ltable"); + + /* Ignore temporary tables as they have already been opened. */ + if (table_list->table) + DBUG_RETURN(table_list->table); + + /* should not be used in a prelocked_mode context, see NOTE above */ + DBUG_ASSERT(thd->locked_tables_mode < LTM_PRELOCKED); + + THD_STAGE_INFO(thd, stage_opening_tables); + thd->current_tablenr= 0; + /* open_ltable can be used only for BASIC TABLEs */ + table_list->required_type= TABLE_TYPE_NORMAL; + + /* This function can't properly handle requests for such metadata locks. */ + DBUG_ASSERT(table_list->mdl_request.type < MDL_SHARED_UPGRADABLE); + + while ((error= open_table(thd, table_list, &ot_ctx)) && + ot_ctx.can_recover_from_failed_open()) + { + /* + Even though we have failed to open table we still need to + call release_transactional_locks() to release metadata locks which + might have been acquired successfully. + */ + thd->mdl_context.rollback_to_savepoint(ot_ctx.start_of_statement_svp()); + table_list->mdl_request.ticket= 0; + if (ot_ctx.recover_from_failed_open()) + break; + } + + if (likely(!error)) + { + /* + We can't have a view or some special "open_strategy" in this function + so there should be a TABLE instance. + */ + DBUG_ASSERT(table_list->table); + table= table_list->table; + if (table->file->ha_table_flags() & HA_CAN_MULTISTEP_MERGE) + { + /* A MERGE table must not come here. */ + /* purecov: begin tested */ + my_error(ER_WRONG_OBJECT, MYF(0), table->s->db.str, + table->s->table_name.str, "BASE TABLE"); + table= 0; + goto end; + /* purecov: end */ + } + + table_list->lock_type= lock_type; + table->grant= table_list->grant; + if (thd->locked_tables_mode) + { + if (check_lock_and_start_stmt(thd, thd->lex, table_list)) + table= 0; + } + else + { + DBUG_ASSERT(thd->lock == 0); // You must lock everything at once + if ((table->reginfo.lock_type= lock_type) != TL_UNLOCK) + if (! (thd->lock= mysql_lock_tables(thd, &table_list->table, 1, + lock_flags))) + { + table= 0; + } + } + } + else + table= 0; + +end: + if (table == NULL) + { + if (!thd->in_sub_stmt) + trans_rollback_stmt(thd); + close_thread_tables(thd); + } + THD_STAGE_INFO(thd, stage_after_opening_tables); + + thd_proc_info(thd, 0); + DBUG_RETURN(table); +} + + +/** + Open all tables in list, locks them and optionally process derived tables. + + @param thd Thread context. + @param options DDL options. + @param tables List of tables for open and locking. + @param derived Whether to handle derived tables. + @param flags Bitmap of options to be used to open and lock + tables (see open_tables() and mysql_lock_tables() + for details). + @param prelocking_strategy Strategy which specifies how prelocking algorithm + should work for this statement. + + @note + The thr_lock locks will automatically be freed by + close_thread_tables(). + + @retval FALSE OK. + @retval TRUE Error +*/ + +bool open_and_lock_tables(THD *thd, const DDL_options_st &options, + TABLE_LIST *tables, + bool derived, uint flags, + Prelocking_strategy *prelocking_strategy) +{ + uint counter; + MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint(); + DBUG_ENTER("open_and_lock_tables"); + DBUG_PRINT("enter", ("derived handling: %d", derived)); + + if (open_tables(thd, options, &tables, &counter, flags, prelocking_strategy)) + goto err; + + DBUG_EXECUTE_IF("sleep_open_and_lock_after_open", { + const char *old_proc_info= thd->proc_info; + thd->proc_info= "DBUG sleep"; + my_sleep(6000000); + thd->proc_info= old_proc_info;}); + + if (lock_tables(thd, tables, counter, flags)) + goto err; + + /* Don't read statistics tables when opening internal tables */ + if (!(flags & MYSQL_OPEN_IGNORE_LOGGING_FORMAT)) + (void) read_statistics_for_tables_if_needed(thd, tables); + + if (derived) + { + if (mysql_handle_derived(thd->lex, DT_INIT)) + goto err; + if (thd->prepare_derived_at_open && + (mysql_handle_derived(thd->lex, DT_PREPARE))) + goto err; + } + + DBUG_RETURN(FALSE); +err: + if (! thd->in_sub_stmt) + trans_rollback_stmt(thd); /* Necessary if derived handling failed. */ + close_thread_tables(thd); + /* Don't keep locks for a failed statement. */ + thd->mdl_context.rollback_to_savepoint(mdl_savepoint); + DBUG_RETURN(TRUE); +} + + +/* + Open all tables in list and process derived tables + + SYNOPSIS + open_normal_and_derived_tables + thd - thread handler + tables - list of tables for open + flags - bitmap of flags to modify how the tables will be open: + MYSQL_LOCK_IGNORE_FLUSH - open table even if someone has + done a flush on it. + dt_phases - set of flags to pass to the mysql_handle_derived + + RETURN + FALSE - ok + TRUE - error + + NOTE + This is to be used on prepare stage when you don't read any + data from the tables. +*/ + +bool open_normal_and_derived_tables(THD *thd, TABLE_LIST *tables, uint flags, + uint dt_phases) +{ + DML_prelocking_strategy prelocking_strategy; + uint counter; + MDL_savepoint mdl_savepoint= thd->mdl_context.mdl_savepoint(); + DBUG_ENTER("open_normal_and_derived_tables"); + if (open_tables(thd, &tables, &counter, flags, &prelocking_strategy) || + mysql_handle_derived(thd->lex, dt_phases)) + goto end; + + DBUG_RETURN(0); +end: + /* + No need to commit/rollback the statement transaction: it's + either not started or we're filling in an INFORMATION_SCHEMA + table on the fly, and thus mustn't manipulate with the + transaction of the enclosing statement. + */ + DBUG_ASSERT(thd->transaction->stmt.is_empty() || + (thd->state_flags & Open_tables_state::BACKUPS_AVAIL)); + close_thread_tables(thd); + /* Don't keep locks for a failed statement. */ + thd->mdl_context.rollback_to_savepoint(mdl_savepoint); + + DBUG_RETURN(TRUE); /* purecov: inspected */ +} + + +/** + Open a table to read its structure, e.g. for: + - SHOW FIELDS + - delayed SP variable data type definition: DECLARE a t1.a%TYPE + + The flag MYSQL_OPEN_GET_NEW_TABLE is passed to make %TYPE work + in stored functions, as during a stored function call + (e.g. in a SELECT query) the tables referenced in %TYPE can already be locked, + and attempt to open it again would return an error in open_table(). + + The flag MYSQL_OPEN_GET_NEW_TABLE is not really needed for + SHOW FIELDS or for a "CALL sp()" statement, but it's not harmful, + so let's pass it unconditionally. +*/ + +bool open_tables_only_view_structure(THD *thd, TABLE_LIST *table_list, + bool can_deadlock) +{ + DBUG_ENTER("open_tables_only_view_structure"); + /* + Let us set fake sql_command so views won't try to merge + themselves into main statement. If we don't do this, + SELECT * from information_schema.xxxx will cause problems. + SQLCOM_SHOW_FIELDS is used because it satisfies + 'LEX::only_view_structure()'. + */ + enum_sql_command save_sql_command= thd->lex->sql_command; + thd->lex->sql_command= SQLCOM_SHOW_FIELDS; + bool rc= (thd->open_temporary_tables(table_list) || + open_normal_and_derived_tables(thd, table_list, + (MYSQL_OPEN_IGNORE_FLUSH | + MYSQL_OPEN_FORCE_SHARED_HIGH_PRIO_MDL | + MYSQL_OPEN_GET_NEW_TABLE | + (can_deadlock ? + MYSQL_OPEN_FAIL_ON_MDL_CONFLICT : 0)), + DT_INIT | DT_PREPARE)); + /* + Restore old value of sql_command back as it is being looked at in + process_table() function. + */ + thd->lex->sql_command= save_sql_command; + DBUG_RETURN(rc); +} + + +/* + Mark all real tables in the list as free for reuse. + + SYNOPSIS + mark_real_tables_as_free_for_reuse() + thd - thread context + table - head of the list of tables + + DESCRIPTION + Marks all real tables in the list (i.e. not views, derived + or schema tables) as free for reuse. +*/ + +static void mark_real_tables_as_free_for_reuse(TABLE_LIST *table_list) +{ + TABLE_LIST *table; + DBUG_ENTER("mark_real_tables_as_free_for_reuse"); + + /* + We have to make two loops as HA_EXTRA_DETACH_CHILDREN may + remove items from the table list that we have to reset + */ + for (table= table_list; table; table= table->next_global) + { + if (!table->placeholder()) + table->table->query_id= 0; + } + for (table= table_list; table; table= table->next_global) + { + if (!table->placeholder()) + { + /* + Detach children of MyISAMMRG tables used in + sub-statements, they will be reattached at open. + This has to be done in a separate loop to make sure + that children have had their query_id cleared. + */ + table->table->file->extra(HA_EXTRA_DETACH_CHILDREN); + } + } + DBUG_VOID_RETURN; +} + +int TABLE::fix_vcol_exprs(THD *thd) +{ + for (Field **vf= vfield; vf && *vf; vf++) + if (fix_session_vcol_expr(thd, (*vf)->vcol_info)) + return 1; + + for (Field **df= default_field; df && *df; df++) + if ((*df)->default_value && + fix_session_vcol_expr(thd, (*df)->default_value)) + return 1; + + for (Virtual_column_info **cc= check_constraints; cc && *cc; cc++) + if (fix_session_vcol_expr(thd, (*cc))) + return 1; + + return 0; +} + + +static bool fix_all_session_vcol_exprs(THD *thd, TABLE_LIST *tables) +{ + Security_context *save_security_ctx= thd->security_ctx; + TABLE_LIST *first_not_own= thd->lex->first_not_own_table(); + DBUG_ENTER("fix_session_vcol_expr"); + + int error= 0; + for (TABLE_LIST *table= tables; table && table != first_not_own && !error; + table= table->next_global) + { + TABLE *t= table->table; + if (!table->placeholder() && t->s->vcols_need_refixing && + table->lock_type >= TL_WRITE_ALLOW_WRITE) + { + Query_arena *stmt_backup= thd->stmt_arena; + if (thd->stmt_arena->is_conventional()) + thd->stmt_arena= t->expr_arena; + if (table->security_ctx) + thd->security_ctx= table->security_ctx; + + error= t->fix_vcol_exprs(thd); + + thd->security_ctx= save_security_ctx; + thd->stmt_arena= stmt_backup; + } + } + DBUG_RETURN(error); +} + + +/** + Lock all tables in a list. + + @param thd Thread handler + @param tables Tables to lock + @param count Number of opened tables + @param flags Options (see mysql_lock_tables() for details) + + You can't call lock_tables() while holding thr_lock locks, as + this would break the dead-lock-free handling thr_lock gives us. + You must always get all needed locks at once. + + If the query for which we are calling this function is marked as + requiring prelocking, this function will change + locked_tables_mode to LTM_PRELOCKED. + + @retval FALSE Success. + @retval TRUE A lock wait timeout, deadlock or out of memory. +*/ + +bool lock_tables(THD *thd, TABLE_LIST *tables, uint count, uint flags) +{ + TABLE_LIST *table, *first_not_own; + DBUG_ENTER("lock_tables"); + /* + We can't meet statement requiring prelocking if we already + in prelocked mode. + */ + DBUG_ASSERT(thd->locked_tables_mode <= LTM_LOCK_TABLES || + !thd->lex->requires_prelocking()); + + if (!tables && !thd->lex->requires_prelocking()) + DBUG_RETURN(0); + + first_not_own= thd->lex->first_not_own_table(); + + /* + Check for thd->locked_tables_mode to avoid a redundant + and harmful attempt to lock the already locked tables again. + Checking for thd->lock is not enough in some situations. For example, + if a stored function contains + "drop table t3; create temporary t3 ..; insert into t3 ...;" + thd->lock may be 0 after drop tables, whereas locked_tables_mode + is still on. In this situation an attempt to lock temporary + table t3 will lead to a memory leak. + */ + if (! thd->locked_tables_mode) + { + DBUG_ASSERT(thd->lock == 0); // You must lock everything at once + TABLE **start,**ptr; + bool found_first_not_own= 0; + + if (!(ptr=start=(TABLE**) thd->alloc(sizeof(TABLE*)*count))) + DBUG_RETURN(TRUE); + + /* + Collect changes tables for table lock. + Mark own tables with query id as this is needed by + prepare_for_row_logging() + */ + for (table= tables; table; table= table->next_global) + { + if (table == first_not_own) + found_first_not_own= 1; + if (!table->placeholder()) + { + *(ptr++)= table->table; + if (!found_first_not_own) + table->table->query_id= thd->query_id; + } + } + + DEBUG_SYNC(thd, "before_lock_tables_takes_lock"); + + if (! (thd->lock= mysql_lock_tables(thd, start, (uint) (ptr - start), + flags))) + DBUG_RETURN(TRUE); + + DEBUG_SYNC(thd, "after_lock_tables_takes_lock"); + + if (thd->lex->requires_prelocking() && + thd->lex->sql_command != SQLCOM_LOCK_TABLES) + { + /* + We just have done implicit LOCK TABLES, and now we have + to emulate first open_and_lock_tables() after it. + + When open_and_lock_tables() is called for a single table out of + a table list, the 'next_global' chain is temporarily broken. We + may not find 'first_not_own' before the end of the "list". + Look for example at those places where open_n_lock_single_table() + is called. That function implements the temporary breaking of + a table list for opening a single table. + */ + for (table= tables; + table && table != first_not_own; + table= table->next_global) + { + if (!table->placeholder()) + { + if (check_lock_and_start_stmt(thd, thd->lex, table)) + { + mysql_unlock_tables(thd, thd->lock); + thd->lock= 0; + DBUG_RETURN(TRUE); + } + } + } + /* + Let us mark all tables which don't belong to the statement itself, + and was marked as occupied during open_tables() as free for reuse. + */ + mark_real_tables_as_free_for_reuse(first_not_own); + DBUG_PRINT("info",("locked_tables_mode= LTM_PRELOCKED")); + thd->enter_locked_tables_mode(LTM_PRELOCKED); + } + } + else + { + /* + When open_and_lock_tables() is called for a single table out of + a table list, the 'next_global' chain is temporarily broken. We + may not find 'first_not_own' before the end of the "list". + Look for example at those places where open_n_lock_single_table() + is called. That function implements the temporary breaking of + a table list for opening a single table. + */ + for (table= tables; + table && table != first_not_own; + table= table->next_global) + { + if (table->placeholder()) + continue; + + table->table->query_id= thd->query_id; + /* + In a stored function or trigger we should ensure that we won't change + a table that is already used by the calling statement. + */ + if (thd->locked_tables_mode >= LTM_PRELOCKED && + table->lock_type >= TL_WRITE_ALLOW_WRITE) + { + for (TABLE* opentab= thd->open_tables; opentab; opentab= opentab->next) + { + if (table->table->s == opentab->s && opentab->query_id && + table->table->query_id != opentab->query_id) + { + my_error(ER_CANT_UPDATE_USED_TABLE_IN_SF_OR_TRG, MYF(0), + table->table->s->table_name.str); + DBUG_RETURN(TRUE); + } + } + } + + if (check_lock_and_start_stmt(thd, thd->lex, table)) + { + DBUG_RETURN(TRUE); + } + } + /* + If we are under explicit LOCK TABLES and our statement requires + prelocking, we should mark all "additional" tables as free for use + and enter prelocked mode. + */ + if (thd->lex->requires_prelocking()) + { + mark_real_tables_as_free_for_reuse(first_not_own); + DBUG_PRINT("info", + ("thd->locked_tables_mode= LTM_PRELOCKED_UNDER_LOCK_TABLES")); + thd->locked_tables_mode= LTM_PRELOCKED_UNDER_LOCK_TABLES; + } + } + + bool res= fix_all_session_vcol_exprs(thd, tables); + if (!res && !(flags & MYSQL_OPEN_IGNORE_LOGGING_FORMAT)) + res= thd->decide_logging_format(tables); + + DBUG_RETURN(res); +} + + +/* + Restart transaction for tables + + This is used when we had to do an implicit commit after tables are opened + and want to restart transactions on tables. + + This is used in case of: + LOCK TABLES xx + CREATE OR REPLACE TABLE xx; +*/ + +bool restart_trans_for_tables(THD *thd, TABLE_LIST *table) +{ + DBUG_ENTER("restart_trans_for_tables"); + + for (; table; table= table->next_global) + { + if (table->placeholder()) + continue; + + if (check_lock_and_start_stmt(thd, thd->lex, table)) + { + DBUG_ASSERT(0); // Should never happen + DBUG_RETURN(TRUE); + } + } + DBUG_RETURN(FALSE); +} + + +/** + Prepare statement for reopening of tables and recalculation of set of + prelocked tables. + + @param[in] thd Thread context. + @param[in,out] tables List of tables which we were trying to open + and lock. + @param[in] start_of_statement_svp MDL savepoint which represents the set + of metadata locks which the current transaction + managed to acquire before execution of the current + statement and to which we should revert before + trying to reopen tables. NULL if no metadata locks + were held and thus all metadata locks should be + released. +*/ + +void close_tables_for_reopen(THD *thd, TABLE_LIST **tables, + const MDL_savepoint &start_of_statement_svp) +{ + TABLE_LIST *first_not_own_table= thd->lex->first_not_own_table(); + TABLE_LIST *tmp; + + /* + If table list consists only from tables from prelocking set, table list + for new attempt should be empty, so we have to update list's root pointer. + */ + if (first_not_own_table == *tables) + *tables= 0; + thd->lex->chop_off_not_own_tables(); + /* Reset MDL tickets for procedures/functions */ + for (Sroutine_hash_entry *rt= + (Sroutine_hash_entry*)thd->lex->sroutines_list.first; + rt; rt= rt->next) + rt->mdl_request.ticket= NULL; + sp_remove_not_own_routines(thd->lex); + for (tmp= *tables; tmp; tmp= tmp->next_global) + { + tmp->table= 0; + tmp->mdl_request.ticket= NULL; + /* We have to cleanup translation tables of views. */ + tmp->cleanup_items(); + } + /* + No need to commit/rollback the statement transaction: it's + either not started or we're filling in an INFORMATION_SCHEMA + table on the fly, and thus mustn't manipulate with the + transaction of the enclosing statement. + */ + DBUG_ASSERT(thd->transaction->stmt.is_empty() || + (thd->state_flags & Open_tables_state::BACKUPS_AVAIL)); + close_thread_tables(thd); + thd->mdl_context.rollback_to_savepoint(start_of_statement_svp); +} + + +/***************************************************************************** +* The following find_field_in_XXX procedures implement the core of the +* name resolution functionality. The entry point to resolve a column name in a +* list of tables is 'find_field_in_tables'. It calls 'find_field_in_table_ref' +* for each table reference. In turn, depending on the type of table reference, +* 'find_field_in_table_ref' calls one of the 'find_field_in_XXX' procedures +* below specific for the type of table reference. +******************************************************************************/ + +/* Special Field pointers as return values of find_field_in_XXX functions. */ +Field *not_found_field= (Field*) 0x1; +Field *view_ref_found= (Field*) 0x2; + +#define WRONG_GRANT (Field*) -1 + +static void update_field_dependencies(THD *thd, Field *field, TABLE *table) +{ + DBUG_ENTER("update_field_dependencies"); + if (should_mark_column(thd->column_usage)) + { + /* + We always want to register the used keys, as the column bitmap may have + been set for all fields (for example for view). + */ + table->covering_keys.intersect(field->part_of_key); + + if (thd->column_usage == MARK_COLUMNS_READ) + { + if (table->mark_column_with_deps(field)) + DBUG_VOID_RETURN; // Field was already marked + } + else + { + if (bitmap_fast_test_and_set(table->write_set, field->field_index)) + { + DBUG_PRINT("warning", ("Found duplicated field")); + thd->dup_field= field; + DBUG_VOID_RETURN; + } + } + + table->used_fields++; + } + if (table->get_fields_in_item_tree) + field->flags|= GET_FIXED_FIELDS_FLAG; + DBUG_VOID_RETURN; +} + + +/* + Find a field by name in a view that uses merge algorithm. + + SYNOPSIS + find_field_in_view() + thd thread handler + table_list view to search for 'name' + name name of field + length length of name + item_name name of item if it will be created (VIEW) + ref expression substituted in VIEW should be passed + using this reference (return view_ref_found) + register_tree_change TRUE if ref is not stack variable and we + need register changes in item tree + + RETURN + 0 field is not found + view_ref_found found value in VIEW (real result is in *ref) + # pointer to field - only for schema table fields +*/ + +static Field * +find_field_in_view(THD *thd, TABLE_LIST *table_list, + const char *name, size_t length, + const char *item_name, Item **ref, + bool register_tree_change) +{ + DBUG_ENTER("find_field_in_view"); + DBUG_PRINT("enter", + ("view: '%s', field name: '%s', item name: '%s', ref %p", + table_list->alias.str, name, item_name, ref)); + Field_iterator_view field_it; + field_it.set(table_list); + Query_arena *arena= 0, backup; + + for (; !field_it.end_of_fields(); field_it.next()) + { + if (!my_strcasecmp(system_charset_info, field_it.name()->str, name)) + { + // in PS use own arena or data will be freed after prepare + if (register_tree_change && + thd->stmt_arena->is_stmt_prepare_or_first_stmt_execute()) + arena= thd->activate_stmt_arena_if_needed(&backup); + /* + create_item() may, or may not create a new Item, depending on + the column reference. See create_view_field() for details. + */ + Item *item= field_it.create_item(thd); + if (arena) + thd->restore_active_arena(arena, &backup); + + if (!item) + DBUG_RETURN(0); + if (!ref) + DBUG_RETURN((Field*) view_ref_found); + /* + *ref != NULL means that *ref contains the item that we need to + replace. If the item was aliased by the user, set the alias to + the replacing item. + */ + if (*ref && !(*ref)->is_autogenerated_name()) + item->set_name(thd, (*ref)->name); + if (register_tree_change) + thd->change_item_tree(ref, item); + else + *ref= item; + DBUG_RETURN((Field*) view_ref_found); + } + } + DBUG_RETURN(0); +} + + +/* + Find field by name in a NATURAL/USING join table reference. + + SYNOPSIS + find_field_in_natural_join() + thd [in] thread handler + table_ref [in] table reference to search + name [in] name of field + length [in] length of name + ref [in/out] if 'name' is resolved to a view field, ref is + set to point to the found view field + register_tree_change [in] TRUE if ref is not stack variable and we + need register changes in item tree + actual_table [out] the original table reference where the field + belongs - differs from 'table_list' only for + NATURAL/USING joins + + DESCRIPTION + Search for a field among the result fields of a NATURAL/USING join. + Notice that this procedure is called only for non-qualified field + names. In the case of qualified fields, we search directly the base + tables of a natural join. + + RETURN + NULL if the field was not found + WRONG_GRANT if no access rights to the found field + # Pointer to the found Field +*/ + +static Field * +find_field_in_natural_join(THD *thd, TABLE_LIST *table_ref, const char *name, size_t length, Item **ref, bool register_tree_change, + TABLE_LIST **actual_table) +{ + List_iterator_fast<Natural_join_column> + field_it(*(table_ref->join_columns)); + Natural_join_column *nj_col, *curr_nj_col; + Field *UNINIT_VAR(found_field); + Query_arena *UNINIT_VAR(arena), backup; + DBUG_ENTER("find_field_in_natural_join"); + DBUG_PRINT("enter", ("field name: '%s', ref %p", + name, ref)); + DBUG_ASSERT(table_ref->is_natural_join && table_ref->join_columns); + DBUG_ASSERT(*actual_table == NULL); + + for (nj_col= NULL, curr_nj_col= field_it++; curr_nj_col; + curr_nj_col= field_it++) + { + if (!my_strcasecmp(system_charset_info, curr_nj_col->name()->str, name)) + { + if (nj_col) + { + my_error(ER_NON_UNIQ_ERROR, MYF(0), name, thd->where); + DBUG_RETURN(NULL); + } + nj_col= curr_nj_col; + } + } + if (!nj_col) + DBUG_RETURN(NULL); + + if (nj_col->view_field) + { + Item *item; + if (register_tree_change) + arena= thd->activate_stmt_arena_if_needed(&backup); + /* + create_item() may, or may not create a new Item, depending on the + column reference. See create_view_field() for details. + */ + item= nj_col->create_item(thd); + if (!item) + DBUG_RETURN(NULL); + + /* + *ref != NULL means that *ref contains the item that we need to + replace. If the item was aliased by the user, set the alias to + the replacing item. + */ + if (*ref && !(*ref)->is_autogenerated_name()) + item->set_name(thd, (*ref)->name); + if (register_tree_change && arena) + thd->restore_active_arena(arena, &backup); + + if (!item) + DBUG_RETURN(NULL); + DBUG_ASSERT(nj_col->table_field == NULL); + if (nj_col->table_ref->schema_table_reformed) + { + /* + Translation table items are always Item_fields and fixed + already('mysql_schema_table' function). So we can return + ->field. It is used only for 'show & where' commands. + */ + DBUG_RETURN(((Item_field*) (nj_col->view_field->item))->field); + } + if (register_tree_change) + thd->change_item_tree(ref, item); + else + *ref= item; + found_field= (Field*) view_ref_found; + } + else + { + /* This is a base table. */ + DBUG_ASSERT(nj_col->view_field == NULL); + Item *ref= 0; + /* + This fix_fields is not necessary (initially this item is fixed by + the Item_field constructor; after reopen_tables the Item_func_eq + calls fix_fields on that item), it's just a check during table + reopening for columns that was dropped by the concurrent connection. + */ + if (nj_col->table_field->fix_fields_if_needed(thd, &ref)) + { + DBUG_PRINT("info", ("column '%s' was dropped by the concurrent connection", + nj_col->table_field->name.str)); + DBUG_RETURN(NULL); + } + DBUG_ASSERT(ref == 0); // Should not have changed + DBUG_ASSERT(nj_col->table_ref->table == nj_col->table_field->field->table); + found_field= nj_col->table_field->field; + update_field_dependencies(thd, found_field, nj_col->table_ref->table); + } + + *actual_table= nj_col->table_ref; + + DBUG_RETURN(found_field); +} + + +/* + Find field by name in a base table or a view with temp table algorithm. + + The caller is expected to check column-level privileges. + + SYNOPSIS + find_field_in_table() + thd thread handler + table table where to search for the field + name name of field + length length of name + allow_rowid do allow finding of "_rowid" field? + cached_field_index_ptr cached position in field list (used to speedup + lookup for fields in prepared tables) + + RETURN + 0 field is not found + # pointer to field +*/ + +Field * +find_field_in_table(THD *thd, TABLE *table, const char *name, size_t length, + bool allow_rowid, uint *cached_field_index_ptr) +{ + Field *field; + uint cached_field_index= *cached_field_index_ptr; + DBUG_ENTER("find_field_in_table"); + DBUG_PRINT("enter", ("table: '%s', field name: '%s'", table->alias.c_ptr(), + name)); + + /* We assume here that table->field < NO_CACHED_FIELD_INDEX = UINT_MAX */ + if (cached_field_index < table->s->fields && + !my_strcasecmp(system_charset_info, + table->field[cached_field_index]->field_name.str, name)) + field= table->field[cached_field_index]; + else + { + LEX_CSTRING fname= {name, length}; + field= table->find_field_by_name(&fname); + } + + if (field) + { + if (field->invisible == INVISIBLE_FULL && + DBUG_EVALUATE_IF("test_completely_invisible", 0, 1)) + DBUG_RETURN((Field*)0); + + if (field->invisible == INVISIBLE_SYSTEM && + thd->column_usage != MARK_COLUMNS_READ && + thd->column_usage != COLUMNS_READ) + DBUG_RETURN((Field*)0); + } + else + { + if (!allow_rowid || + my_strcasecmp(system_charset_info, name, "_rowid") || + table->s->rowid_field_offset == 0) + DBUG_RETURN((Field*) 0); + field= table->field[table->s->rowid_field_offset-1]; + } + *cached_field_index_ptr= field->field_index; + + update_field_dependencies(thd, field, table); + + DBUG_RETURN(field); +} + + +/* + Find field in a table reference. + + SYNOPSIS + find_field_in_table_ref() + thd [in] thread handler + table_list [in] table reference to search + name [in] name of field + length [in] field length of name + item_name [in] name of item if it will be created (VIEW) + db_name [in] optional database name that qualifies the + table_name [in] optional table name that qualifies the field + 0 for non-qualified field in natural joins + ref [in/out] if 'name' is resolved to a view field, ref + is set to point to the found view field + check_privileges [in] check privileges + allow_rowid [in] do allow finding of "_rowid" field? + cached_field_index_ptr [in] cached position in field list (used to + speedup lookup for fields in prepared tables) + register_tree_change [in] TRUE if ref is not stack variable and we + need register changes in item tree + actual_table [out] the original table reference where the field + belongs - differs from 'table_list' only for + NATURAL_USING joins. + + DESCRIPTION + Find a field in a table reference depending on the type of table + reference. There are three types of table references with respect + to the representation of their result columns: + - an array of Field_translator objects for MERGE views and some + information_schema tables, + - an array of Field objects (and possibly a name hash) for stored + tables, + - a list of Natural_join_column objects for NATURAL/USING joins. + This procedure detects the type of the table reference 'table_list' + and calls the corresponding search routine. + + The routine checks column-level privieleges for the found field. + + RETURN + 0 field is not found + view_ref_found found value in VIEW (real result is in *ref) + # pointer to field +*/ + +Field * +find_field_in_table_ref(THD *thd, TABLE_LIST *table_list, + const char *name, size_t length, + const char *item_name, const char *db_name, + const char *table_name, Item **ref, + bool check_privileges, bool allow_rowid, + uint *cached_field_index_ptr, + bool register_tree_change, TABLE_LIST **actual_table) +{ + Field *fld; + DBUG_ENTER("find_field_in_table_ref"); + DBUG_ASSERT(table_list->alias.str); + DBUG_ASSERT(name); + DBUG_ASSERT(item_name); + DBUG_PRINT("enter", + ("table: '%s' field name: '%s' item name: '%s' ref %p", + table_list->alias.str, name, item_name, ref)); + + /* + Check that the table and database that qualify the current field name + are the same as the table reference we are going to search for the field. + + Exclude from the test below nested joins because the columns in a + nested join generally originate from different tables. Nested joins + also have no table name, except when a nested join is a merge view + or an information schema table. + + We include explicitly table references with a 'field_translation' table, + because if there are views over natural joins we don't want to search + inside the view, but we want to search directly in the view columns + which are represented as a 'field_translation'. + + tables->db.str may be 0 if we are preparing a statement + db_name is 0 if item doesn't have a db name + table_name is 0 if item doesn't have a specified table_name + */ + if (db_name && !db_name[0]) + db_name= 0; // Simpler test later + + if (/* Exclude nested joins. */ + (!table_list->nested_join || + /* Include merge views and information schema tables. */ + table_list->field_translation) && + /* + Test if the field qualifiers match the table reference we plan + to search. + */ + table_name && table_name[0] && + (my_strcasecmp(table_alias_charset, table_list->alias.str, table_name) || + (db_name && (!table_list->db.str || !table_list->db.str[0])) || + (db_name && table_list->db.str && table_list->db.str[0] && + (table_list->schema_table ? + my_strcasecmp(system_charset_info, db_name, table_list->db.str) : + strcmp(db_name, table_list->db.str))))) + DBUG_RETURN(0); + + /* + Don't allow usage of fields in sequence table that is opened as part of + NEXT VALUE for sequence_name + */ + if (table_list->sequence) + DBUG_RETURN(0); + + *actual_table= NULL; + + if (table_list->field_translation) + { + /* 'table_list' is a view or an information schema table. */ + if ((fld= find_field_in_view(thd, table_list, name, length, item_name, ref, + register_tree_change))) + *actual_table= table_list; + } + else if (!table_list->nested_join) + { + /* 'table_list' is a stored table. */ + DBUG_ASSERT(table_list->table); + if ((fld= find_field_in_table(thd, table_list->table, name, length, + allow_rowid, + cached_field_index_ptr))) + *actual_table= table_list; + } + else + { + /* + 'table_list' is a NATURAL/USING join, or an operand of such join that + is a nested join itself. + + If the field name we search for is qualified, then search for the field + in the table references used by NATURAL/USING the join. + */ + if (table_name && table_name[0]) + { + List_iterator<TABLE_LIST> it(table_list->nested_join->join_list); + TABLE_LIST *table; + while ((table= it++)) + { + if ((fld= find_field_in_table_ref(thd, table, name, length, item_name, + db_name, table_name, ref, + check_privileges, allow_rowid, + cached_field_index_ptr, + register_tree_change, actual_table))) + DBUG_RETURN(fld); + } + DBUG_RETURN(0); + } + /* + Non-qualified field, search directly in the result columns of the + natural join. The condition of the outer IF is true for the top-most + natural join, thus if the field is not qualified, we will search + directly the top-most NATURAL/USING join. + */ + fld= find_field_in_natural_join(thd, table_list, name, length, ref, + register_tree_change, actual_table); + } + + if (fld) + { +#ifndef NO_EMBEDDED_ACCESS_CHECKS + /* Check if there are sufficient access rights to the found field. */ + if (check_privileges && + !table_list->is_derived() && + check_column_grant_in_table_ref(thd, *actual_table, name, length, fld)) + fld= WRONG_GRANT; + else +#endif + if (should_mark_column(thd->column_usage)) + { + /* + Get rw_set correct for this field so that the handler + knows that this field is involved in the query and gets + retrieved/updated + */ + Field *field_to_set= NULL; + if (fld == view_ref_found) + { + if (!ref) + DBUG_RETURN(fld); + Item *it= (*ref)->real_item(); + if (it->type() == Item::FIELD_ITEM) + field_to_set= ((Item_field*)it)->field; + else + { + if (thd->column_usage == MARK_COLUMNS_READ) + it->walk(&Item::register_field_in_read_map, 0, 0); + else + it->walk(&Item::register_field_in_write_map, 0, 0); + } + } + else + field_to_set= fld; + if (field_to_set) + { + TABLE *table= field_to_set->table; + DBUG_ASSERT(table); + if (thd->column_usage == MARK_COLUMNS_READ) + field_to_set->register_field_in_read_map(); + else + bitmap_set_bit(table->write_set, field_to_set->field_index); + } + } + } + DBUG_RETURN(fld); +} + + +/* + Find field in table, no side effects, only purpose is to check for field + in table object and get reference to the field if found. + + SYNOPSIS + find_field_in_table_sef() + + table table where to find + name Name of field searched for + + RETURN + 0 field is not found + # pointer to field +*/ + +Field *find_field_in_table_sef(TABLE *table, const char *name) +{ + Field **field_ptr; + if (table->s->name_hash.records) + { + field_ptr= (Field**)my_hash_search(&table->s->name_hash,(uchar*) name, + strlen(name)); + if (field_ptr) + { + /* + field_ptr points to field in TABLE_SHARE. Convert it to the matching + field in table + */ + field_ptr= (table->field + (field_ptr - table->s->field)); + } + } + else + { + if (!(field_ptr= table->field)) + return (Field *)0; + for (; *field_ptr; ++field_ptr) + if (!my_strcasecmp(system_charset_info, (*field_ptr)->field_name.str, + name)) + break; + } + if (field_ptr) + return *field_ptr; + else + return (Field *)0; +} + + +/* + Find field in table list. + + SYNOPSIS + find_field_in_tables() + thd pointer to current thread structure + item field item that should be found + first_table list of tables to be searched for item + last_table end of the list of tables to search for item. If NULL + then search to the end of the list 'first_table'. + ref if 'item' is resolved to a view field, ref is set to + point to the found view field + report_error Degree of error reporting: + - IGNORE_ERRORS then do not report any error + - IGNORE_EXCEPT_NON_UNIQUE report only non-unique + fields, suppress all other errors + - REPORT_EXCEPT_NON_UNIQUE report all other errors + except when non-unique fields were found + - REPORT_ALL_ERRORS + check_privileges need to check privileges + register_tree_change TRUE if ref is not a stack variable and we + to need register changes in item tree + + RETURN VALUES + 0 If error: the found field is not unique, or there are + no sufficient access priviliges for the found field, + or the field is qualified with non-existing table. + not_found_field The function was called with report_error == + (IGNORE_ERRORS || IGNORE_EXCEPT_NON_UNIQUE) and a + field was not found. + view_ref_found View field is found, item passed through ref parameter + found field If a item was resolved to some field +*/ + +Field * +find_field_in_tables(THD *thd, Item_ident *item, + TABLE_LIST *first_table, TABLE_LIST *last_table, + Item **ref, find_item_error_report_type report_error, + bool check_privileges, bool register_tree_change) +{ + Field *found=0; + const char *db= item->db_name.str; + const char *table_name= item->table_name.str; + const char *name= item->field_name.str; + size_t length= item->field_name.length; + char name_buff[SAFE_NAME_LEN+1]; + TABLE_LIST *cur_table= first_table; + TABLE_LIST *actual_table; + bool allow_rowid; + + if (!table_name || !table_name[0]) + { + table_name= 0; // For easier test + db= 0; + } + + allow_rowid= table_name || (cur_table && !cur_table->next_local); + + if (item->cached_table) + { + DBUG_PRINT("info", ("using cached table")); + /* + This shortcut is used by prepared statements. We assume that + TABLE_LIST *first_table is not changed during query execution (which + is true for all queries except RENAME but luckily RENAME doesn't + use fields...) so we can rely on reusing pointer to its member. + With this optimization we also miss case when addition of one more + field makes some prepared query ambiguous and so erroneous, but we + accept this trade off. + */ + TABLE_LIST *table_ref= item->cached_table; + /* + The condition (table_ref->view == NULL) ensures that we will call + find_field_in_table even in the case of information schema tables + when table_ref->field_translation != NULL. + */ + if (table_ref->table && !table_ref->view && + (!table_ref->is_merged_derived() || + (!table_ref->is_multitable() && table_ref->merged_for_insert))) + { + + found= find_field_in_table(thd, table_ref->table, name, length, + TRUE, &(item->cached_field_index)); +#ifndef NO_EMBEDDED_ACCESS_CHECKS + /* Check if there are sufficient access rights to the found field. */ + if (found && check_privileges && + check_column_grant_in_table_ref(thd, table_ref, name, length, found)) + found= WRONG_GRANT; +#endif + } + else + found= find_field_in_table_ref(thd, table_ref, name, length, item->name.str, + NULL, NULL, ref, check_privileges, + TRUE, &(item->cached_field_index), + register_tree_change, + &actual_table); + if (found) + { + if (found == WRONG_GRANT) + return (Field*) 0; + + /* + Only views fields should be marked as dependent, not an underlying + fields. + */ + if (!table_ref->belong_to_view && + !table_ref->belong_to_derived) + { + SELECT_LEX *current_sel= item->context->select_lex; + SELECT_LEX *last_select= table_ref->select_lex; + bool all_merged= TRUE; + for (SELECT_LEX *sl= current_sel; sl && sl!=last_select; + sl=sl->outer_select()) + { + Item_in_subselect *in_subs= + sl->master_unit()->item->get_IN_subquery(); + if (in_subs && + in_subs->substype() == Item_subselect::IN_SUBS && + in_subs->test_strategy(SUBS_SEMI_JOIN)) + { + continue; + } + all_merged= FALSE; + break; + } + /* + If the field was an outer referencee, mark all selects using this + sub query as dependent on the outer query + */ + if (!all_merged && current_sel != last_select) + { + mark_select_range_as_dependent(thd, last_select, current_sel, + found, *ref, item, true); + } + } + return found; + } + } + else + item->can_be_depended= TRUE; + + if (db && lower_case_table_names) + { + /* + convert database to lower case for comparison. + We can't do this in Item_field as this would change the + 'name' of the item which may be used in the select list + */ + strmake_buf(name_buff, db); + my_casedn_str(files_charset_info, name_buff); + db= name_buff; + } + + if (last_table) + last_table= last_table->next_name_resolution_table; + + for (; cur_table != last_table ; + cur_table= cur_table->next_name_resolution_table) + { + Field *cur_field= find_field_in_table_ref(thd, cur_table, name, length, + item->name.str, db, table_name, ref, + (thd->lex->sql_command == + SQLCOM_SHOW_FIELDS) + ? false : check_privileges, + allow_rowid, + &(item->cached_field_index), + register_tree_change, + &actual_table); + if (cur_field) + { + if (cur_field == WRONG_GRANT) + { + if (thd->lex->sql_command != SQLCOM_SHOW_FIELDS) + return (Field*) 0; + + thd->clear_error(); + cur_field= find_field_in_table_ref(thd, cur_table, name, length, + item->name.str, db, table_name, ref, + false, + allow_rowid, + &(item->cached_field_index), + register_tree_change, + &actual_table); + if (cur_field) + { + Field *nf=new Field_null(NULL,0,Field::NONE, + &cur_field->field_name, + &my_charset_bin); + nf->init(cur_table->table); + cur_field= nf; + } + } + + /* + Store the original table of the field, which may be different from + cur_table in the case of NATURAL/USING join. + */ + item->cached_table= (!actual_table->cacheable_table || found) ? + 0 : actual_table; + + DBUG_ASSERT(thd->where); + /* + If we found a fully qualified field we return it directly as it can't + have duplicates. + */ + if (db) + return cur_field; + + if (unlikely(found)) + { + if (report_error == REPORT_ALL_ERRORS || + report_error == IGNORE_EXCEPT_NON_UNIQUE) + my_error(ER_NON_UNIQ_ERROR, MYF(0), + table_name ? item->full_name() : name, thd->where); + return (Field*) 0; + } + found= cur_field; + } + } + + if (likely(found)) + return found; + + /* + If the field was qualified and there were no tables to search, issue + an error that an unknown table was given. The situation is detected + as follows: if there were no tables we wouldn't go through the loop + and cur_table wouldn't be updated by the loop increment part, so it + will be equal to the first table. + */ + if (table_name && (cur_table == first_table) && + (report_error == REPORT_ALL_ERRORS || + report_error == REPORT_EXCEPT_NON_UNIQUE)) + { + char buff[SAFE_NAME_LEN*2 + 2]; + if (db && db[0]) + { + strxnmov(buff,sizeof(buff)-1,db,".",table_name,NullS); + table_name=buff; + } + my_error(ER_UNKNOWN_TABLE, MYF(0), table_name, thd->where); + } + else + { + if (report_error == REPORT_ALL_ERRORS || + report_error == REPORT_EXCEPT_NON_UNIQUE) + my_error(ER_BAD_FIELD_ERROR, MYF(0), item->full_name(), thd->where); + else + found= not_found_field; + } + return found; +} + + +/* + Find Item in list of items (find_field_in_tables analog) + + TODO + is it better return only counter? + + SYNOPSIS + find_item_in_list() + find Item to find + items List of items + counter To return number of found item + report_error + REPORT_ALL_ERRORS report errors, return 0 if error + REPORT_EXCEPT_NOT_FOUND Do not report 'not found' error and + return not_found_item, report other errors, + return 0 + IGNORE_ERRORS Do not report errors, return 0 if error + resolution Set to the resolution type if the item is found + (it says whether the item is resolved + against an alias name, + or as a field name without alias, + or as a field hidden by alias, + or ignoring alias) + limit How many items in the list to check + (if limit==0 then all items are to be checked) + + RETURN VALUES + 0 Item is not found or item is not unique, + error message is reported + not_found_item Function was called with + report_error == REPORT_EXCEPT_NOT_FOUND and + item was not found. No error message was reported + found field +*/ + +/* Special Item pointer to serve as a return value from find_item_in_list(). */ +Item **not_found_item= (Item**) 0x1; + + +Item ** +find_item_in_list(Item *find, List<Item> &items, uint *counter, + find_item_error_report_type report_error, + enum_resolution_type *resolution, uint limit) +{ + List_iterator<Item> li(items); + uint n_items= limit == 0 ? items.elements : limit; + Item **found=0, **found_unaliased= 0, *item; + const char *db_name=0; + const LEX_CSTRING *field_name= 0; + const char *table_name=0; + bool found_unaliased_non_uniq= 0; + /* + true if the item that we search for is a valid name reference + (and not an item that happens to have a name). + */ + bool is_ref_by_name= 0; + uint unaliased_counter= 0; + + *resolution= NOT_RESOLVED; + + is_ref_by_name= (find->type() == Item::FIELD_ITEM || + find->type() == Item::REF_ITEM); + if (is_ref_by_name) + { + field_name= &((Item_ident*) find)->field_name; + table_name= ((Item_ident*) find)->table_name.str; + db_name= ((Item_ident*) find)->db_name.str; + } + + for (uint i= 0; i < n_items; i++) + { + item= li++; + if (field_name && field_name->str && + (item->real_item()->type() == Item::FIELD_ITEM || + ((item->type() == Item::REF_ITEM) && + (((Item_ref *)item)->ref_type() == Item_ref::VIEW_REF)))) + { + Item_ident *item_field= (Item_ident*) item; + + /* + In case of group_concat() with ORDER BY condition in the QUERY + item_field can be field of temporary table without item name + (if this field created from expression argument of group_concat()), + => we have to check presence of name before compare + */ + if (unlikely(!item_field->name.str)) + continue; + + if (table_name) + { + /* + If table name is specified we should find field 'field_name' in + table 'table_name'. According to SQL-standard we should ignore + aliases in this case. + + Since we should NOT prefer fields from the select list over + other fields from the tables participating in this select in + case of ambiguity we have to do extra check outside this function. + + We use strcmp for table names and database names as these may be + case sensitive. In cases where they are not case sensitive, they + are always in lower case. + + item_field->field_name and item_field->table_name can be 0x0 if + item is not fix_field()'ed yet. + */ + if (item_field->field_name.str && item_field->table_name.str && + !lex_string_cmp(system_charset_info, &item_field->field_name, + field_name) && + !my_strcasecmp(table_alias_charset, item_field->table_name.str, + table_name) && + (!db_name || (item_field->db_name.str && + !strcmp(item_field->db_name.str, db_name)))) + { + if (found_unaliased) + { + if ((*found_unaliased)->eq(item, 0)) + continue; + /* + Two matching fields in select list. + We already can bail out because we are searching through + unaliased names only and will have duplicate error anyway. + */ + if (report_error != IGNORE_ERRORS) + my_error(ER_NON_UNIQ_ERROR, MYF(0), + find->full_name(), current_thd->where); + return (Item**) 0; + } + found_unaliased= li.ref(); + unaliased_counter= i; + *resolution= RESOLVED_IGNORING_ALIAS; + if (db_name) + break; // Perfect match + } + } + else + { + bool fname_cmp= lex_string_cmp(system_charset_info, + &item_field->field_name, + field_name); + if (!lex_string_cmp(system_charset_info, + &item_field->name, field_name)) + { + /* + If table name was not given we should scan through aliases + and non-aliased fields first. We are also checking unaliased + name of the field in then next else-if, to be able to find + instantly field (hidden by alias) if no suitable alias or + non-aliased field was found. + */ + if (found) + { + if ((*found)->eq(item, 0)) + continue; // Same field twice + if (report_error != IGNORE_ERRORS) + my_error(ER_NON_UNIQ_ERROR, MYF(0), + find->full_name(), current_thd->where); + return (Item**) 0; + } + found= li.ref(); + *counter= i; + *resolution= fname_cmp ? RESOLVED_AGAINST_ALIAS: + RESOLVED_WITH_NO_ALIAS; + } + else if (!fname_cmp) + { + /* + We will use non-aliased field or react on such ambiguities only if + we won't be able to find aliased field. + Again if we have ambiguity with field outside of select list + we should prefer fields from select list. + */ + if (found_unaliased) + { + if ((*found_unaliased)->eq(item, 0)) + continue; // Same field twice + found_unaliased_non_uniq= 1; + } + found_unaliased= li.ref(); + unaliased_counter= i; + } + } + } + else if (!table_name) + { + if (is_ref_by_name && find->name.str && item->name.str && + find->name.length == item->name.length && + !lex_string_cmp(system_charset_info, &item->name, &find->name)) + { + found= li.ref(); + *counter= i; + *resolution= RESOLVED_AGAINST_ALIAS; + break; + } + else if (find->eq(item,0)) + { + found= li.ref(); + *counter= i; + *resolution= RESOLVED_IGNORING_ALIAS; + break; + } + } + } + + if (likely(found)) + return found; + + if (unlikely(found_unaliased_non_uniq)) + { + if (report_error != IGNORE_ERRORS) + my_error(ER_NON_UNIQ_ERROR, MYF(0), + find->full_name(), current_thd->where); + return (Item **) 0; + } + if (found_unaliased) + { + found= found_unaliased; + *counter= unaliased_counter; + *resolution= RESOLVED_BEHIND_ALIAS; + } + + if (found) + return found; + + if (report_error != REPORT_EXCEPT_NOT_FOUND) + { + if (report_error == REPORT_ALL_ERRORS) + my_error(ER_BAD_FIELD_ERROR, MYF(0), + find->full_name(), current_thd->where); + return (Item **) 0; + } + else + return (Item **) not_found_item; +} + + +/* + Test if a string is a member of a list of strings. + + SYNOPSIS + test_if_string_in_list() + find the string to look for + str_list a list of strings to be searched + + DESCRIPTION + Sequentially search a list of strings for a string, and test whether + the list contains the same string. + + RETURN + TRUE if find is in str_list + FALSE otherwise +*/ + +static bool +test_if_string_in_list(const char *find, List<String> *str_list) +{ + List_iterator<String> str_list_it(*str_list); + String *curr_str; + size_t find_length= strlen(find); + while ((curr_str= str_list_it++)) + { + if (find_length != curr_str->length()) + continue; + if (!my_strcasecmp(system_charset_info, find, curr_str->ptr())) + return TRUE; + } + return FALSE; +} + + +/* + Create a new name resolution context for an item so that it is + being resolved in a specific table reference. + + SYNOPSIS + set_new_item_local_context() + thd pointer to current thread + item item for which new context is created and set + table_ref table ref where an item showld be resolved + + DESCRIPTION + Create a new name resolution context for an item, so that the item + is resolved only the supplied 'table_ref'. + + RETURN + FALSE if all OK + TRUE otherwise +*/ + +static bool +set_new_item_local_context(THD *thd, Item_ident *item, TABLE_LIST *table_ref) +{ + Name_resolution_context *context; + if (!(context= new (thd->mem_root) Name_resolution_context)) + return TRUE; + context->init(); + context->first_name_resolution_table= + context->last_name_resolution_table= table_ref; + item->context= context; + return FALSE; +} + + +/* + Find and mark the common columns of two table references. + + SYNOPSIS + mark_common_columns() + thd [in] current thread + table_ref_1 [in] the first (left) join operand + table_ref_2 [in] the second (right) join operand + using_fields [in] if the join is JOIN...USING - the join columns, + if NATURAL join, then NULL + found_using_fields [out] number of fields from the USING clause that were + found among the common fields + + DESCRIPTION + The procedure finds the common columns of two relations (either + tables or intermediate join results), and adds an equi-join condition + to the ON clause of 'table_ref_2' for each pair of matching columns. + If some of table_ref_XXX represents a base table or view, then we + create new 'Natural_join_column' instances for each column + reference and store them in the 'join_columns' of the table + reference. + + IMPLEMENTATION + The procedure assumes that store_natural_using_join_columns() was + called for the previous level of NATURAL/USING joins. + + RETURN + TRUE error when some common column is non-unique, or out of memory + FALSE OK +*/ + +static bool +mark_common_columns(THD *thd, TABLE_LIST *table_ref_1, TABLE_LIST *table_ref_2, + List<String> *using_fields, uint *found_using_fields) +{ + Field_iterator_table_ref it_1, it_2; + Natural_join_column *nj_col_1, *nj_col_2; + Query_arena *arena, backup; + bool result= TRUE; + bool first_outer_loop= TRUE; + Field *field_1; + field_visibility_t field_1_invisible, field_2_invisible; + /* + Leaf table references to which new natural join columns are added + if the leaves are != NULL. + */ + TABLE_LIST *leaf_1= (table_ref_1->nested_join && + !table_ref_1->is_natural_join) ? + NULL : table_ref_1; + TABLE_LIST *leaf_2= (table_ref_2->nested_join && + !table_ref_2->is_natural_join) ? + NULL : table_ref_2; + + DBUG_ENTER("mark_common_columns"); + DBUG_PRINT("info", ("operand_1: %s operand_2: %s", + table_ref_1->alias.str, table_ref_2->alias.str)); + + *found_using_fields= 0; + arena= thd->activate_stmt_arena_if_needed(&backup); + + for (it_1.set(table_ref_1); !it_1.end_of_fields(); it_1.next()) + { + bool found= FALSE; + const LEX_CSTRING *field_name_1; + Field *field_2= 0; + + /* true if field_name_1 is a member of using_fields */ + bool is_using_column_1; + if (!(nj_col_1= it_1.get_or_create_column_ref(thd, leaf_1))) + goto err; + + field_1= nj_col_1->field(); + field_1_invisible= field_1 ? field_1->invisible : VISIBLE; + + if (field_1_invisible == INVISIBLE_FULL) + continue; + + field_name_1= nj_col_1->name(); + is_using_column_1= using_fields && + test_if_string_in_list(field_name_1->str, using_fields); + DBUG_PRINT ("info", ("field_name_1=%s.%s", + nj_col_1->safe_table_name(), + field_name_1->str)); + + if (field_1_invisible && !is_using_column_1) + continue; + + /* + Find a field with the same name in table_ref_2. + + Note that for the second loop, it_2.set() will iterate over + table_ref_2->join_columns and not generate any new elements or + lists. + */ + nj_col_2= NULL; + for (it_2.set(table_ref_2); !it_2.end_of_fields(); it_2.next()) + { + Natural_join_column *cur_nj_col_2; + const LEX_CSTRING *cur_field_name_2; + if (!(cur_nj_col_2= it_2.get_or_create_column_ref(thd, leaf_2))) + goto err; + + field_2= cur_nj_col_2->field(); + field_2_invisible= field_2 ? field_2->invisible : VISIBLE; + + if (field_2_invisible == INVISIBLE_FULL) + continue; + + cur_field_name_2= cur_nj_col_2->name(); + DBUG_PRINT ("info", ("cur_field_name_2=%s.%s", + cur_nj_col_2->safe_table_name(), + cur_field_name_2->str)); + + /* + Compare the two columns and check for duplicate common fields. + A common field is duplicate either if it was already found in + table_ref_2 (then found == TRUE), or if a field in table_ref_2 + was already matched by some previous field in table_ref_1 + (then cur_nj_col_2->is_common == TRUE). + Note that it is too early to check the columns outside of the + USING list for ambiguity because they are not actually "referenced" + here. These columns must be checked only on unqualified reference + by name (e.g. in SELECT list). + */ + if (!lex_string_cmp(system_charset_info, field_name_1, + cur_field_name_2)) + { + DBUG_PRINT ("info", ("match c1.is_common=%d", nj_col_1->is_common)); + if (cur_nj_col_2->is_common || found) + { + my_error(ER_NON_UNIQ_ERROR, MYF(0), field_name_1->str, thd->where); + goto err; + } + if ((!using_fields && !field_2_invisible) || is_using_column_1) + { + DBUG_ASSERT(nj_col_2 == NULL); + nj_col_2= cur_nj_col_2; + found= TRUE; + } + } + } + if (first_outer_loop && leaf_2) + { + /* + Make sure that the next inner loop "knows" that all columns + are materialized already. + */ + leaf_2->is_join_columns_complete= TRUE; + first_outer_loop= FALSE; + } + if (!found) + continue; // No matching field + + /* + field_1 and field_2 have the same names. Check if they are in the USING + clause (if present), mark them as common fields, and add a new + equi-join condition to the ON clause. + */ + if (nj_col_2) + { + /* + Create non-fixed fully qualified field and let fix_fields to + resolve it. + */ + Item *item_1= nj_col_1->create_item(thd); + Item *item_2= nj_col_2->create_item(thd); + Item_ident *item_ident_1, *item_ident_2; + Item_func_eq *eq_cond; + + if (!item_1 || !item_2) + goto err; // out of memory + + /* + The following assert checks that the two created items are of + type Item_ident. + */ + DBUG_ASSERT(!thd->lex->current_select->no_wrap_view_item); + /* + In the case of no_wrap_view_item == 0, the created items must be + of sub-classes of Item_ident. + */ + DBUG_ASSERT(item_1->type() == Item::FIELD_ITEM || + item_1->type() == Item::REF_ITEM); + DBUG_ASSERT(item_2->type() == Item::FIELD_ITEM || + item_2->type() == Item::REF_ITEM); + + /* + We need to cast item_1,2 to Item_ident, because we need to hook name + resolution contexts specific to each item. + */ + item_ident_1= (Item_ident*) item_1; + item_ident_2= (Item_ident*) item_2; + /* + Create and hook special name resolution contexts to each item in the + new join condition . We need this to both speed-up subsequent name + resolution of these items, and to enable proper name resolution of + the items during the execute phase of PS. + */ + if (set_new_item_local_context(thd, item_ident_1, nj_col_1->table_ref) || + set_new_item_local_context(thd, item_ident_2, nj_col_2->table_ref)) + goto err; + + if (!(eq_cond= new (thd->mem_root) Item_func_eq(thd, item_ident_1, item_ident_2))) + goto err; /* Out of memory. */ + + /* + Add the new equi-join condition to the ON clause. Notice that + fix_fields() is applied to all ON conditions in setup_conds() + so we don't do it here. + */ + add_join_on(thd, (table_ref_1->outer_join & JOIN_TYPE_RIGHT ? + table_ref_1 : table_ref_2), + eq_cond); + + nj_col_1->is_common= nj_col_2->is_common= TRUE; + DBUG_PRINT ("info", ("%s.%s and %s.%s are common", + nj_col_1->safe_table_name(), + nj_col_1->name()->str, + nj_col_2->safe_table_name(), + nj_col_2->name()->str)); + + if (field_1) + update_field_dependencies(thd, field_1, field_1->table); + if (field_2) + update_field_dependencies(thd, field_2, field_2->table); + + if (using_fields != NULL) + ++(*found_using_fields); + } + } + if (leaf_1) + leaf_1->is_join_columns_complete= TRUE; + + /* + Everything is OK. + Notice that at this point there may be some column names in the USING + clause that are not among the common columns. This is an SQL error and + we check for this error in store_natural_using_join_columns() when + (found_using_fields < length(join_using_fields)). + */ + result= FALSE; + +err: + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(result); +} + + + +/* + Materialize and store the row type of NATURAL/USING join. + + SYNOPSIS + store_natural_using_join_columns() + thd current thread + natural_using_join the table reference of the NATURAL/USING join + table_ref_1 the first (left) operand (of a NATURAL/USING join). + table_ref_2 the second (right) operand (of a NATURAL/USING join). + using_fields if the join is JOIN...USING - the join columns, + if NATURAL join, then NULL + found_using_fields number of fields from the USING clause that were + found among the common fields + + DESCRIPTION + Iterate over the columns of both join operands and sort and store + all columns into the 'join_columns' list of natural_using_join + where the list is formed by three parts: + part1: The coalesced columns of table_ref_1 and table_ref_2, + sorted according to the column order of the first table. + part2: The other columns of the first table, in the order in + which they were defined in CREATE TABLE. + part3: The other columns of the second table, in the order in + which they were defined in CREATE TABLE. + Time complexity - O(N1+N2), where Ni = length(table_ref_i). + + IMPLEMENTATION + The procedure assumes that mark_common_columns() has been called + for the join that is being processed. + + RETURN + TRUE error: Some common column is ambiguous + FALSE OK +*/ + +static bool +store_natural_using_join_columns(THD *thd, TABLE_LIST *natural_using_join, + TABLE_LIST *table_ref_1, + TABLE_LIST *table_ref_2, + List<String> *using_fields, + uint found_using_fields) +{ + Field_iterator_table_ref it_1, it_2; + Natural_join_column *nj_col_1, *nj_col_2; + Query_arena *arena, backup; + bool result= TRUE; + List<Natural_join_column> *non_join_columns; + List<Natural_join_column> *join_columns; + DBUG_ENTER("store_natural_using_join_columns"); + + DBUG_ASSERT(!natural_using_join->join_columns); + + arena= thd->activate_stmt_arena_if_needed(&backup); + + if (!(non_join_columns= new List<Natural_join_column>) || + !(join_columns= new List<Natural_join_column>)) + goto err; + + /* Append the columns of the first join operand. */ + for (it_1.set(table_ref_1); !it_1.end_of_fields(); it_1.next()) + { + nj_col_1= it_1.get_natural_column_ref(); + if (nj_col_1->is_common) + { + join_columns->push_back(nj_col_1, thd->mem_root); + /* Reset the common columns for the next call to mark_common_columns. */ + nj_col_1->is_common= FALSE; + } + else + non_join_columns->push_back(nj_col_1, thd->mem_root); + } + + /* + Check that all columns in the USING clause are among the common + columns. If this is not the case, report the first one that was + not found in an error. + */ + if (using_fields && found_using_fields < using_fields->elements) + { + String *using_field_name; + List_iterator_fast<String> using_fields_it(*using_fields); + while ((using_field_name= using_fields_it++)) + { + const char *using_field_name_ptr= using_field_name->c_ptr(); + List_iterator_fast<Natural_join_column> + it(*join_columns); + Natural_join_column *common_field; + + for (;;) + { + /* If reached the end of fields, and none was found, report error. */ + if (!(common_field= it++)) + { + my_error(ER_BAD_FIELD_ERROR, MYF(0), using_field_name_ptr, + current_thd->where); + goto err; + } + if (!my_strcasecmp(system_charset_info, + common_field->name()->str, using_field_name_ptr)) + break; // Found match + } + } + } + + /* Append the non-equi-join columns of the second join operand. */ + for (it_2.set(table_ref_2); !it_2.end_of_fields(); it_2.next()) + { + nj_col_2= it_2.get_natural_column_ref(); + if (!nj_col_2->is_common) + non_join_columns->push_back(nj_col_2, thd->mem_root); + else + { + /* Reset the common columns for the next call to mark_common_columns. */ + nj_col_2->is_common= FALSE; + } + } + + if (non_join_columns->elements > 0) + join_columns->append(non_join_columns); + natural_using_join->join_columns= join_columns; + natural_using_join->is_join_columns_complete= TRUE; + + result= FALSE; + + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(result); + +err: + /* + Actually we failed to build join columns list, so we have to + clear it to avoid problems with half-build join on next run. + The list was created in mark_common_columns(). + */ + table_ref_1->remove_join_columns(); + table_ref_2->remove_join_columns(); + + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(TRUE); +} + + +/* + Precompute and store the row types of the top-most NATURAL/USING joins. + + SYNOPSIS + store_top_level_join_columns() + thd current thread + table_ref nested join or table in a FROM clause + left_neighbor neighbor table reference to the left of table_ref at the + same level in the join tree + right_neighbor neighbor table reference to the right of table_ref at the + same level in the join tree + + DESCRIPTION + The procedure performs a post-order traversal of a nested join tree + and materializes the row types of NATURAL/USING joins in a + bottom-up manner until it reaches the TABLE_LIST elements that + represent the top-most NATURAL/USING joins. The procedure should be + applied to each element of SELECT_LEX::top_join_list (i.e. to each + top-level element of the FROM clause). + + IMPLEMENTATION + Notice that the table references in the list nested_join->join_list + are in reverse order, thus when we iterate over it, we are moving + from the right to the left in the FROM clause. + + RETURN + TRUE Error + FALSE OK +*/ + +static bool +store_top_level_join_columns(THD *thd, TABLE_LIST *table_ref, + TABLE_LIST *left_neighbor, + TABLE_LIST *right_neighbor) +{ + Query_arena *arena, backup; + bool result= TRUE; + + DBUG_ENTER("store_top_level_join_columns"); + + arena= thd->activate_stmt_arena_if_needed(&backup); + + /* Call the procedure recursively for each nested table reference. */ + if (table_ref->nested_join) + { + List_iterator_fast<TABLE_LIST> nested_it(table_ref->nested_join->join_list); + TABLE_LIST *same_level_left_neighbor= nested_it++; + TABLE_LIST *same_level_right_neighbor= NULL; + /* Left/right-most neighbors, possibly at higher levels in the join tree. */ + TABLE_LIST *real_left_neighbor, *real_right_neighbor; + + while (same_level_left_neighbor) + { + TABLE_LIST *cur_table_ref= same_level_left_neighbor; + same_level_left_neighbor= nested_it++; + /* + The order of RIGHT JOIN operands is reversed in 'join list' to + transform it into a LEFT JOIN. However, in this procedure we need + the join operands in their lexical order, so below we reverse the + join operands. Notice that this happens only in the first loop, + and not in the second one, as in the second loop + same_level_left_neighbor == NULL. + This is the correct behavior, because the second loop sets + cur_table_ref reference correctly after the join operands are + swapped in the first loop. + */ + if (same_level_left_neighbor && + cur_table_ref->outer_join & JOIN_TYPE_RIGHT) + { + /* This can happen only for JOIN ... ON. */ + DBUG_ASSERT(table_ref->nested_join->join_list.elements == 2); + swap_variables(TABLE_LIST*, same_level_left_neighbor, cur_table_ref); + } + + /* + Pick the parent's left and right neighbors if there are no immediate + neighbors at the same level. + */ + real_left_neighbor= (same_level_left_neighbor) ? + same_level_left_neighbor : left_neighbor; + real_right_neighbor= (same_level_right_neighbor) ? + same_level_right_neighbor : right_neighbor; + + if (cur_table_ref->nested_join && + store_top_level_join_columns(thd, cur_table_ref, + real_left_neighbor, real_right_neighbor)) + goto err; + same_level_right_neighbor= cur_table_ref; + } + } + + /* + If this is a NATURAL/USING join, materialize its result columns and + convert to a JOIN ... ON. + */ + if (table_ref->is_natural_join) + { + DBUG_ASSERT(table_ref->nested_join && + table_ref->nested_join->join_list.elements == 2); + List_iterator_fast<TABLE_LIST> operand_it(table_ref->nested_join->join_list); + /* + Notice that the order of join operands depends on whether table_ref + represents a LEFT or a RIGHT join. In a RIGHT join, the operands are + in inverted order. + */ + TABLE_LIST *table_ref_2= operand_it++; /* Second NATURAL join operand.*/ + TABLE_LIST *table_ref_1= operand_it++; /* First NATURAL join operand. */ + List<String> *using_fields= table_ref->join_using_fields; + uint found_using_fields; + + /* + The two join operands were interchanged in the parser, change the order + back for 'mark_common_columns'. + */ + if (table_ref_2->outer_join & JOIN_TYPE_RIGHT) + swap_variables(TABLE_LIST*, table_ref_1, table_ref_2); + if (mark_common_columns(thd, table_ref_1, table_ref_2, + using_fields, &found_using_fields)) + goto err; + + /* + Swap the join operands back, so that we pick the columns of the second + one as the coalesced columns. In this way the coalesced columns are the + same as of an equivalent LEFT JOIN. + */ + if (table_ref_1->outer_join & JOIN_TYPE_RIGHT) + swap_variables(TABLE_LIST*, table_ref_1, table_ref_2); + if (store_natural_using_join_columns(thd, table_ref, table_ref_1, + table_ref_2, using_fields, + found_using_fields)) + goto err; + + /* + Change NATURAL JOIN to JOIN ... ON. We do this for both operands + because either one of them or the other is the one with the + natural join flag because RIGHT joins are transformed into LEFT, + and the two tables may be reordered. + */ + table_ref_1->natural_join= table_ref_2->natural_join= NULL; + + /* Add a TRUE condition to outer joins that have no common columns. */ + if (table_ref_2->outer_join && + !table_ref_1->on_expr && !table_ref_2->on_expr) + table_ref_2->on_expr= new (thd->mem_root) Item_int(thd, (longlong) 1, 1); // Always true. + + /* Change this table reference to become a leaf for name resolution. */ + if (left_neighbor) + { + TABLE_LIST *last_leaf_on_the_left; + last_leaf_on_the_left= left_neighbor->last_leaf_for_name_resolution(); + last_leaf_on_the_left->next_name_resolution_table= table_ref; + } + if (right_neighbor) + { + TABLE_LIST *first_leaf_on_the_right; + first_leaf_on_the_right= right_neighbor->first_leaf_for_name_resolution(); + table_ref->next_name_resolution_table= first_leaf_on_the_right; + } + else + table_ref->next_name_resolution_table= NULL; + } + result= FALSE; /* All is OK. */ + +err: + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(result); +} + + +/* + Compute and store the row types of the top-most NATURAL/USING joins + in a FROM clause. + + SYNOPSIS + setup_natural_join_row_types() + thd current thread + from_clause list of top-level table references in a FROM clause + + DESCRIPTION + Apply the procedure 'store_top_level_join_columns' to each of the + top-level table referencs of the FROM clause. Adjust the list of tables + for name resolution - context->first_name_resolution_table to the + top-most, lef-most NATURAL/USING join. + + IMPLEMENTATION + Notice that the table references in 'from_clause' are in reverse + order, thus when we iterate over it, we are moving from the right + to the left in the FROM clause. + + NOTES + We can't run this many times as the first_name_resolution_table would + be different for subsequent runs when sub queries has been optimized + away. + + RETURN + TRUE Error + FALSE OK +*/ + +static bool setup_natural_join_row_types(THD *thd, + List<TABLE_LIST> *from_clause, + Name_resolution_context *context) +{ + DBUG_ENTER("setup_natural_join_row_types"); + thd->where= "from clause"; + if (from_clause->elements == 0) + DBUG_RETURN(false); /* We come here in the case of UNIONs. */ + + /* + Do not redo work if already done: + 1) for stored procedures, + 2) for multitable update after lock failure and table reopening. + */ + if (!context->select_lex->first_natural_join_processing) + { + context->first_name_resolution_table= context->natural_join_first_table; + DBUG_PRINT("info", ("using cached setup_natural_join_row_types")); + DBUG_RETURN(false); + } + + List_iterator_fast<TABLE_LIST> table_ref_it(*from_clause); + TABLE_LIST *table_ref; /* Current table reference. */ + /* Table reference to the left of the current. */ + TABLE_LIST *left_neighbor; + /* Table reference to the right of the current. */ + TABLE_LIST *right_neighbor= NULL; + + /* Note that tables in the list are in reversed order */ + for (left_neighbor= table_ref_it++; left_neighbor ; ) + { + table_ref= left_neighbor; + do + { + left_neighbor= table_ref_it++; + } + while (left_neighbor && left_neighbor->sj_subq_pred); + + if (store_top_level_join_columns(thd, table_ref, + left_neighbor, right_neighbor)) + DBUG_RETURN(true); + if (left_neighbor) + { + TABLE_LIST *first_leaf_on_the_right; + first_leaf_on_the_right= table_ref->first_leaf_for_name_resolution(); + left_neighbor->next_name_resolution_table= first_leaf_on_the_right; + } + right_neighbor= table_ref; + } + + /* + Store the top-most, left-most NATURAL/USING join, so that we start + the search from that one instead of context->table_list. At this point + right_neighbor points to the left-most top-level table reference in the + FROM clause. + */ + DBUG_ASSERT(right_neighbor); + context->first_name_resolution_table= + right_neighbor->first_leaf_for_name_resolution(); + /* + This is only to ensure that first_name_resolution_table doesn't + change on re-execution + */ + context->natural_join_first_table= context->first_name_resolution_table; + context->select_lex->first_natural_join_processing= false; + DBUG_RETURN (false); +} + + +/**************************************************************************** +** Expand all '*' in given fields +****************************************************************************/ + +int setup_wild(THD *thd, TABLE_LIST *tables, List<Item> &fields, + List<Item> *sum_func_list, SELECT_LEX *select_lex, bool returning_field) +{ + Item *item; + List_iterator<Item> it(fields); + Query_arena *arena, backup; + DBUG_ENTER("setup_wild"); + + if (!select_lex->with_wild) + DBUG_RETURN(0); + + /* + Don't use arena if we are not in prepared statements or stored procedures + For PS/SP we have to use arena to remember the changes + */ + arena= thd->activate_stmt_arena_if_needed(&backup); + + thd->lex->current_select->cur_pos_in_select_list= 0; + while (select_lex->with_wild && (item= it++)) + { + if (item->type() == Item::FIELD_ITEM && + ((Item_field*) item)->field_name.str == star_clex_str.str && + !((Item_field*) item)->field) + { + uint elem= fields.elements; + bool any_privileges= ((Item_field *) item)->any_privileges; + Item_subselect *subsel= thd->lex->current_select->master_unit()->item; + if (subsel && + subsel->substype() == Item_subselect::EXISTS_SUBS) + { + /* + It is EXISTS(SELECT * ...) and we can replace * by any constant. + + Item_int do not need fix_fields() because it is basic constant. + */ + it.replace(new (thd->mem_root) Item_int(thd, "Not_used", (longlong) 1, + MY_INT64_NUM_DECIMAL_DIGITS)); + } + else if (insert_fields(thd, ((Item_field*) item)->context, + ((Item_field*) item)->db_name.str, + ((Item_field*) item)->table_name.str, &it, + any_privileges, &select_lex->hidden_bit_fields, returning_field)) + { + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(-1); + } + if (sum_func_list) + { + /* + sum_func_list is a list that has the fields list as a tail. + Because of this we have to update the element count also for this + list after expanding the '*' entry. + */ + sum_func_list->elements+= fields.elements - elem; + } + select_lex->with_wild--; + } + else + thd->lex->current_select->cur_pos_in_select_list++; + } + DBUG_ASSERT(!select_lex->with_wild); + thd->lex->current_select->cur_pos_in_select_list= UNDEF_POS; + if (arena) + thd->restore_active_arena(arena, &backup); + DBUG_RETURN(0); +} + +/**************************************************************************** +** Check that all given fields exists and fill struct with current data +****************************************************************************/ + +bool setup_fields(THD *thd, Ref_ptr_array ref_pointer_array, + List<Item> &fields, enum_column_usage column_usage, + List<Item> *sum_func_list, List<Item> *pre_fix, + bool allow_sum_func) +{ + Item *item; + enum_column_usage saved_column_usage= thd->column_usage; + nesting_map save_allow_sum_func= thd->lex->allow_sum_func; + List_iterator<Item> it(fields); + bool save_is_item_list_lookup; + bool make_pre_fix= (pre_fix && (pre_fix->elements == 0)); + DBUG_ENTER("setup_fields"); + DBUG_PRINT("enter", ("ref_pointer_array: %p", ref_pointer_array.array())); + + thd->column_usage= column_usage; + DBUG_PRINT("info", ("thd->column_usage: %d", thd->column_usage)); + if (allow_sum_func) + thd->lex->allow_sum_func.set_bit(thd->lex->current_select->nest_level); + thd->where= THD::DEFAULT_WHERE; + save_is_item_list_lookup= thd->lex->current_select->is_item_list_lookup; + thd->lex->current_select->is_item_list_lookup= 0; + + /* + To prevent fail on forward lookup we fill it with zeroes, + then if we got pointer on zero after find_item_in_list we will know + that it is forward lookup. + + There is other way to solve problem: fill array with pointers to list, + but it will be slower. + + TODO: remove it when (if) we made one list for allfields and + ref_pointer_array + */ + if (!ref_pointer_array.is_null()) + { + DBUG_ASSERT(ref_pointer_array.size() >= fields.elements); + memset(ref_pointer_array.array(), 0, sizeof(Item *) * fields.elements); + } + + /* + We call set_entry() there (before fix_fields() of the whole list of field + items) because: + 1) the list of field items has same order as in the query, and the + Item_func_get_user_var item may go before the Item_func_set_user_var: + SELECT @a, @a := 10 FROM t; + 2) The entry->update_query_id value controls constantness of + Item_func_get_user_var items, so in presence of Item_func_set_user_var + items we have to refresh their entries before fixing of + Item_func_get_user_var items. + */ + List_iterator<Item_func_set_user_var> li(thd->lex->set_var_list); + Item_func_set_user_var *var; + while ((var= li++)) + var->set_entry(thd, FALSE); + + Ref_ptr_array ref= ref_pointer_array; + thd->lex->current_select->cur_pos_in_select_list= 0; + while ((item= it++)) + { + if (make_pre_fix) + pre_fix->push_back(item, thd->stmt_arena->mem_root); + + if (item->fix_fields_if_needed_for_scalar(thd, it.ref())) + { + thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup; + thd->lex->allow_sum_func= save_allow_sum_func; + thd->column_usage= saved_column_usage; + DBUG_PRINT("info", ("thd->column_usage: %d", thd->column_usage)); + DBUG_RETURN(TRUE); /* purecov: inspected */ + } + item= *(it.ref()); // Item might have changed in fix_fields() + if (!ref.is_null()) + { + ref[0]= item; + ref.pop_front(); + } + /* + split_sum_func() must be called for Window Function items, see + Item_window_func::split_sum_func. + */ + if (sum_func_list && + ((item->with_sum_func() && item->type() != Item::SUM_FUNC_ITEM) || + item->with_window_func)) + { + item->split_sum_func(thd, ref_pointer_array, *sum_func_list, + SPLIT_SUM_SELECT); + } + thd->lex->current_select->select_list_tables|= item->used_tables(); + thd->lex->used_tables|= item->used_tables(); + thd->lex->current_select->cur_pos_in_select_list++; + } + thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup; + thd->lex->current_select->cur_pos_in_select_list= UNDEF_POS; + + thd->lex->allow_sum_func= save_allow_sum_func; + thd->column_usage= saved_column_usage; + DBUG_PRINT("info", ("thd->column_usage: %d", thd->column_usage)); + DBUG_RETURN(MY_TEST(thd->is_error())); +} + + +/* + Perform checks like all given fields exists, if exists fill struct with + current data and expand all '*' in given fields for LEX::returning. + + SYNOPSIS + thd Thread handler + table_list Global/local table list +*/ + +int setup_returning_fields(THD* thd, TABLE_LIST* table_list) +{ + if (!thd->lex->has_returning()) + return 0; + return setup_wild(thd, table_list, thd->lex->returning()->item_list, NULL, + thd->lex->returning(), true) + || setup_fields(thd, Ref_ptr_array(), thd->lex->returning()->item_list, + MARK_COLUMNS_READ, NULL, NULL, false); +} + + +/* + make list of leaves of join table tree + + SYNOPSIS + make_leaves_list() + list pointer to pointer on list first element + tables table list + full_table_list whether to include tables from mergeable derived table/view. + we need them for checks for INSERT/UPDATE statements only. + + RETURN pointer on pointer to next_leaf of last element +*/ + +void make_leaves_list(THD *thd, List<TABLE_LIST> &list, TABLE_LIST *tables, + bool full_table_list, TABLE_LIST *boundary) + +{ + for (TABLE_LIST *table= tables; table; table= table->next_local) + { + if (table == boundary) + full_table_list= !full_table_list; + if (full_table_list && table->is_merged_derived()) + { + SELECT_LEX *select_lex= table->get_single_select(); + /* + It's safe to use select_lex->leaf_tables because all derived + tables/views were already prepared and has their leaf_tables + set properly. + */ + make_leaves_list(thd, list, select_lex->get_table_list(), + full_table_list, boundary); + } + else + { + list.push_back(table, thd->mem_root); + } + } +} + +/* + prepare tables + + SYNOPSIS + setup_tables() + thd Thread handler + context name resolution contest to setup table list there + from_clause Top-level list of table references in the FROM clause + tables Table list (select_lex->table_list) + leaves List of join table leaves list (select_lex->leaf_tables) + refresh It is only refresh for subquery + select_insert It is SELECT ... INSERT command + full_table_list a parameter to pass to the make_leaves_list function + + NOTE + Check also that the 'used keys' and 'ignored keys' exists and set up the + table structure accordingly. + Create a list of leaf tables. For queries with NATURAL/USING JOINs, + compute the row types of the top most natural/using join table references + and link these into a list of table references for name resolution. + + This has to be called for all tables that are used by items, as otherwise + table->map is not set and all Item_field will be regarded as const items. + + RETURN + FALSE ok; In this case *map will includes the chosen index + TRUE error +*/ + +bool setup_tables(THD *thd, Name_resolution_context *context, + List<TABLE_LIST> *from_clause, TABLE_LIST *tables, + List<TABLE_LIST> &leaves, bool select_insert, + bool full_table_list) +{ + uint tablenr= 0; + List_iterator<TABLE_LIST> ti(leaves); + TABLE_LIST *table_list; + + DBUG_ENTER("setup_tables"); + + DBUG_ASSERT ((select_insert && !tables->next_name_resolution_table) || !tables || + (context->table_list && context->first_name_resolution_table)); + /* + this is used for INSERT ... SELECT. + For select we setup tables except first (and its underlying tables) + */ + TABLE_LIST *first_select_table= (select_insert ? + tables->next_local: + 0); + SELECT_LEX *select_lex= select_insert ? thd->lex->first_select_lex() : + thd->lex->current_select; + if (select_lex->first_cond_optimization) + { + leaves.empty(); + if (select_lex->prep_leaf_list_state != SELECT_LEX::SAVED) + { + make_leaves_list(thd, leaves, tables, full_table_list, first_select_table); + select_lex->prep_leaf_list_state= SELECT_LEX::READY; + select_lex->leaf_tables_exec.empty(); + } + else + { + List_iterator_fast <TABLE_LIST> ti(select_lex->leaf_tables_prep); + while ((table_list= ti++)) + leaves.push_back(table_list, thd->mem_root); + } + + while ((table_list= ti++)) + { + TABLE *table= table_list->table; + if (table) + table->pos_in_table_list= table_list; + if (first_select_table && + table_list->top_table() == first_select_table) + { + /* new counting for SELECT of INSERT ... SELECT command */ + first_select_table= 0; + thd->lex->first_select_lex()->insert_tables= tablenr; + tablenr= 0; + } + if(table_list->jtbm_subselect) + { + table_list->jtbm_table_no= tablenr; + } + else if (table) + { + table->pos_in_table_list= table_list; + setup_table_map(table, table_list, tablenr); + + if (table_list->process_index_hints(table)) + DBUG_RETURN(1); + } + tablenr++; + /* + We test the max tables here as we setup_table_map() should not be called + with tablenr >= 64 + */ + if (tablenr > MAX_TABLES) + { + my_error(ER_TOO_MANY_TABLES,MYF(0), static_cast<int>(MAX_TABLES)); + DBUG_RETURN(1); + } + } + } + else + { + List_iterator_fast <TABLE_LIST> ti(select_lex->leaf_tables_exec); + select_lex->leaf_tables.empty(); + while ((table_list= ti++)) + { + if(table_list->jtbm_subselect) + { + table_list->jtbm_table_no= table_list->tablenr_exec; + } + else + { + table_list->table->tablenr= table_list->tablenr_exec; + table_list->table->map= table_list->map_exec; + table_list->table->maybe_null= table_list->maybe_null_exec; + table_list->table->pos_in_table_list= table_list; + if (table_list->process_index_hints(table_list->table)) + DBUG_RETURN(1); + } + select_lex->leaf_tables.push_back(table_list); + } + } + + for (table_list= tables; + table_list; + table_list= table_list->next_local) + { + if (table_list->merge_underlying_list) + { + DBUG_ASSERT(table_list->is_merged_derived()); + Query_arena *arena, backup; + arena= thd->activate_stmt_arena_if_needed(&backup); + bool res; + res= table_list->setup_underlying(thd); + if (arena) + thd->restore_active_arena(arena, &backup); + if (res) + DBUG_RETURN(1); + } + + if (table_list->jtbm_subselect) + { + Item *item= table_list->jtbm_subselect->optimizer; + if (!table_list->jtbm_subselect->optimizer->fixed && + table_list->jtbm_subselect->optimizer->fix_fields(thd, &item)) + { + my_error(ER_TOO_MANY_TABLES,MYF(0), static_cast<int>(MAX_TABLES)); /* psergey-todo: WHY ER_TOO_MANY_TABLES ???*/ + DBUG_RETURN(1); + } + DBUG_ASSERT(item == table_list->jtbm_subselect->optimizer); + } + } + + /* Precompute and store the row types of NATURAL/USING joins. */ + if (setup_natural_join_row_types(thd, from_clause, context)) + DBUG_RETURN(1); + + DBUG_RETURN(0); +} + + +/* + prepare tables and check access for the view tables + + SYNOPSIS + setup_tables_and_check_access() + thd Thread handler + context name resolution contest to setup table list there + from_clause Top-level list of table references in the FROM clause + tables Table list (select_lex->table_list) + conds Condition of current SELECT (can be changed by VIEW) + leaves List of join table leaves list (select_lex->leaf_tables) + refresh It is onle refresh for subquery + select_insert It is SELECT ... INSERT command + want_access what access is needed + full_table_list a parameter to pass to the make_leaves_list function + + NOTE + a wrapper for check_tables that will also check the resulting + table leaves list for access to all the tables that belong to a view + + RETURN + FALSE ok; In this case *map will include the chosen index + TRUE error +*/ +bool setup_tables_and_check_access(THD *thd, Name_resolution_context *context, + List<TABLE_LIST> *from_clause, + TABLE_LIST *tables, + List<TABLE_LIST> &leaves, + bool select_insert, + privilege_t want_access_first, + privilege_t want_access, + bool full_table_list) +{ + DBUG_ENTER("setup_tables_and_check_access"); + + if (setup_tables(thd, context, from_clause, tables, + leaves, select_insert, full_table_list)) + DBUG_RETURN(TRUE); + + List_iterator<TABLE_LIST> ti(leaves); + TABLE_LIST *table_list; + privilege_t access= want_access_first; + while ((table_list= ti++)) + { + if (table_list->belong_to_view && !table_list->view && + check_single_table_access(thd, access, table_list, FALSE)) + { + tables->hide_view_error(thd); + DBUG_RETURN(TRUE); + } + access= want_access; + } + DBUG_RETURN(FALSE); +} + + +/* + Create a key_map from a list of index names + + SYNOPSIS + get_key_map_from_key_list() + map key_map to fill in + table Table + index_list List of index names + + RETURN + 0 ok; In this case *map will includes the choosed index + 1 error +*/ + +bool get_key_map_from_key_list(key_map *map, TABLE *table, + List<String> *index_list) +{ + List_iterator_fast<String> it(*index_list); + String *name; + uint pos; + + map->clear_all(); + while ((name=it++)) + { + if (table->s->keynames.type_names == 0 || + (pos= find_type(&table->s->keynames, name->ptr(), + name->length(), 1)) <= + 0) + { + my_error(ER_KEY_DOES_NOT_EXISTS, MYF(0), name->c_ptr(), + table->pos_in_table_list->alias.str); + map->set_all(); + return 1; + } + map->set_bit(pos-1); + } + return 0; +} + + +/* + Drops in all fields instead of current '*' field + + SYNOPSIS + insert_fields() + thd Thread handler + context Context for name resolution + db_name Database name in case of 'database_name.table_name.*' + table_name Table name in case of 'table_name.*' + it Pointer to '*' + any_privileges 0 If we should ensure that we have SELECT privileges + for all columns + 1 If any privilege is ok + RETURN + 0 ok 'it' is updated to point at last inserted + 1 error. Error message is generated but not sent to client +*/ + +bool +insert_fields(THD *thd, Name_resolution_context *context, const char *db_name, + const char *table_name, List_iterator<Item> *it, + bool any_privileges, uint *hidden_bit_fields, bool returning_field) +{ + Field_iterator_table_ref field_iterator; + bool found; + char name_buff[SAFE_NAME_LEN+1]; + DBUG_ENTER("insert_fields"); + DBUG_PRINT("arena", ("stmt arena: %p",thd->stmt_arena)); + + if (db_name && lower_case_table_names) + { + /* + convert database to lower case for comparison + We can't do this in Item_field as this would change the + 'name' of the item which may be used in the select list + */ + strmake_buf(name_buff, db_name); + my_casedn_str(files_charset_info, name_buff); + db_name= name_buff; + } + + found= FALSE; + + /* + If table names are qualified, then loop over all tables used in the query, + else treat natural joins as leaves and do not iterate over their underlying + tables. + */ + TABLE_LIST *first= context->first_name_resolution_table; + TABLE_LIST *TABLE_LIST::* next= &TABLE_LIST::next_name_resolution_table; + if (table_name && !returning_field) + { + first= context->table_list; + next= &TABLE_LIST::next_local; + } + for (TABLE_LIST *tables= first; tables; tables= tables->*next) + { + Field *field; + TABLE *table= tables->table; + + DBUG_ASSERT(tables->is_leaf_for_name_resolution()); + + if ((table_name && my_strcasecmp(table_alias_charset, table_name, + tables->alias.str)) || + (db_name && strcmp(tables->db.str, db_name))) + continue; + +#ifndef NO_EMBEDDED_ACCESS_CHECKS + /* + Ensure that we have access rights to all fields to be inserted + the table 'tables'. Under some circumstances, this check may be skipped. + + The check is skipped in the following cases: + + - any_privileges is true + + - the table is a derived table + + - the table is a view with SELECT privilege + + - the table is a base table with SELECT privilege + */ + if (!any_privileges && + !tables->is_derived() && + !(tables->is_view() && (tables->grant.privilege & SELECT_ACL)) && + !(table && (table->grant.privilege & SELECT_ACL))) + { + field_iterator.set(tables); + if (check_grant_all_columns(thd, SELECT_ACL, &field_iterator)) + DBUG_RETURN(TRUE); + } +#endif + + /* + Update the tables used in the query based on the referenced fields. For + views and natural joins this update is performed inside the loop below. + */ + if (table) + { + thd->lex->used_tables|= table->map; + thd->lex->current_select->select_list_tables|= table->map; + } + + /* + Initialize a generic field iterator for the current table reference. + Notice that it is guaranteed that this iterator will iterate over the + fields of a single table reference, because 'tables' is a leaf (for + name resolution purposes). + */ + field_iterator.set(tables); + + for (; !field_iterator.end_of_fields(); field_iterator.next()) + { + /* + field() is always NULL for views (see, e.g. Field_iterator_view or + Field_iterator_natural_join). + But view fields can never be invisible. + */ + if ((field= field_iterator.field()) && field->invisible != VISIBLE) + continue; + + Item *item; + + if (!(item= field_iterator.create_item(thd))) + DBUG_RETURN(TRUE); + + /* cache the table for the Item_fields inserted by expanding stars */ + if (item->type() == Item::FIELD_ITEM && tables->cacheable_table) + ((Item_field *)item)->cached_table= tables; + + if (!found) + { + found= TRUE; + it->replace(item); /* Replace '*' with the first found item. */ + } + else + it->after(item); /* Add 'item' to the SELECT list. */ + + if (item->type() == Item::FIELD_ITEM && item->field_type() == MYSQL_TYPE_BIT) + (*hidden_bit_fields)++; + +#ifndef NO_EMBEDDED_ACCESS_CHECKS + /* + Set privilege information for the fields of newly created views. + We have that (any_priviliges == TRUE) if and only if we are creating + a view. In the time of view creation we can't use the MERGE algorithm, + therefore if 'tables' is itself a view, it is represented by a + temporary table. Thus in this case we can be sure that 'item' is an + Item_field. + */ + if (any_privileges && !tables->is_with_table() && !tables->is_derived()) + { + DBUG_ASSERT((tables->field_translation == NULL && table) || + tables->is_natural_join); + DBUG_ASSERT(item->type() == Item::FIELD_ITEM); + Item_field *fld= (Item_field*) item; + const char *field_table_name= field_iterator.get_table_name(); + + if (!tables->schema_table && + !(fld->have_privileges= + (get_column_grant(thd, field_iterator.grant(), + field_iterator.get_db_name(), + field_table_name, fld->field_name.str) & + VIEW_ANY_ACL))) + { + my_error(ER_TABLEACCESS_DENIED_ERROR, MYF(0), "ANY", + thd->security_ctx->priv_user, + thd->security_ctx->host_or_ip, + field_table_name); + DBUG_RETURN(TRUE); + } + } +#endif + + if ((field= field_iterator.field())) + { + field->table->mark_column_with_deps(field); + if (table) + table->covering_keys.intersect(field->part_of_key); + if (tables->is_natural_join) + { + TABLE *field_table; + /* + In this case we are sure that the column ref will not be created + because it was already created and stored with the natural join. + */ + Natural_join_column *nj_col; + if (!(nj_col= field_iterator.get_natural_column_ref())) + DBUG_RETURN(TRUE); + DBUG_ASSERT(nj_col->table_field); + field_table= nj_col->table_ref->table; + if (field_table) + { + thd->lex->used_tables|= field_table->map; + thd->lex->current_select->select_list_tables|= + field_table->map; + field_table->covering_keys.intersect(field->part_of_key); + field_table->used_fields++; + } + } + } + else + thd->lex->used_tables|= item->used_tables(); + thd->lex->current_select->cur_pos_in_select_list++; + } + /* + In case of stored tables, all fields are considered as used, + while in the case of views, the fields considered as used are the + ones marked in setup_tables during fix_fields of view columns. + For NATURAL joins, used_tables is updated in the IF above. + */ + if (table) + table->used_fields= table->s->fields; + } + if (found) + DBUG_RETURN(FALSE); + + /* + TODO: in the case when we skipped all columns because there was a + qualified '*', and all columns were coalesced, we have to give a more + meaningful message than ER_BAD_TABLE_ERROR. + */ + if (!table_name) + my_error(ER_NO_TABLES_USED, MYF(0)); + else if (!db_name && !thd->db.str) + my_error(ER_NO_DB_ERROR, MYF(0)); + else + { + char name[FN_REFLEN]; + my_snprintf(name, sizeof(name), "%s.%s", + db_name ? db_name : thd->get_db(), table_name); + my_error(ER_BAD_TABLE_ERROR, MYF(0), name); + } + + DBUG_RETURN(TRUE); +} + + +/** + Wrap Item_ident + + @param thd thread handle + @param conds pointer to the condition which should be wrapped +*/ + +void wrap_ident(THD *thd, Item **conds) +{ + Item_direct_ref_to_ident *wrapper; + DBUG_ASSERT((*conds)->type() == Item::FIELD_ITEM || (*conds)->type() == Item::REF_ITEM); + Query_arena *arena, backup; + arena= thd->activate_stmt_arena_if_needed(&backup); + if ((wrapper= new (thd->mem_root) Item_direct_ref_to_ident(thd, (Item_ident *) (*conds)))) + (*conds)= (Item*) wrapper; + if (arena) + thd->restore_active_arena(arena, &backup); +} + +/** + Prepare ON expression + + @param thd Thread handle + @param table Pointer to table list + @param is_update Update flag + + @retval TRUE error. + @retval FALSE OK. +*/ + +bool setup_on_expr(THD *thd, TABLE_LIST *table, bool is_update) +{ + uchar buff[STACK_BUFF_ALLOC]; // Max argument in function + if (check_stack_overrun(thd, STACK_MIN_SIZE, buff)) + return TRUE; // Fatal error flag is set! + for(; table; table= table->next_local) + { + TABLE_LIST *embedded; /* The table at the current level of nesting. */ + TABLE_LIST *embedding= table; /* The parent nested table reference. */ + do + { + embedded= embedding; + if (embedded->on_expr) + { + thd->where="on clause"; + embedded->on_expr->mark_as_condition_AND_part(embedded); + if (embedded->on_expr->fix_fields_if_needed_for_bool(thd, + &embedded->on_expr)) + return TRUE; + } + /* + If it's a semi-join nest, fix its "left expression", as it is used by + the SJ-Materialization + */ + if (embedded->sj_subq_pred) + { + Item **left_expr= embedded->sj_subq_pred->left_exp_ptr(); + if ((*left_expr)->fix_fields_if_needed(thd, left_expr)) + return TRUE; + } + + embedding= embedded->embedding; + } + while (embedding && + embedding->nested_join->join_list.head() == embedded); + + if (table->is_merged_derived()) + { + SELECT_LEX *select_lex= table->get_single_select(); + setup_on_expr(thd, select_lex->get_table_list(), is_update); + } + + /* process CHECK OPTION */ + if (is_update) + { + TABLE_LIST *view= table->top_table(); + if (view->effective_with_check) + { + if (view->prepare_check_option(thd)) + return TRUE; + thd->change_item_tree(&table->check_option, view->check_option); + } + } + } + return FALSE; +} + +/* + Fix all conditions and outer join expressions. + + SYNOPSIS + setup_conds() + thd thread handler + tables list of tables for name resolving (select_lex->table_list) + leaves list of leaves of join table tree (select_lex->leaf_tables) + conds WHERE clause + + DESCRIPTION + TODO + + RETURN + TRUE if some error occurred (e.g. out of memory) + FALSE if all is OK +*/ + +int setup_conds(THD *thd, TABLE_LIST *tables, List<TABLE_LIST> &leaves, + COND **conds) +{ + SELECT_LEX *select_lex= thd->lex->current_select; + TABLE_LIST *table= NULL; // For HP compilers + /* + it_is_update set to TRUE when tables of primary SELECT_LEX (SELECT_LEX + which belong to LEX, i.e. most up SELECT) will be updated by + INSERT/UPDATE/LOAD + NOTE: using this condition helps to prevent call of prepare_check_option() + from subquery of VIEW, because tables of subquery belongs to VIEW + (see condition before prepare_check_option() call) + */ + bool it_is_update= (select_lex == thd->lex->first_select_lex()) && + thd->lex->which_check_option_applicable(); + bool save_is_item_list_lookup= select_lex->is_item_list_lookup; + TABLE_LIST *derived= select_lex->master_unit()->derived; + DBUG_ENTER("setup_conds"); + + select_lex->is_item_list_lookup= 0; + + thd->column_usage= MARK_COLUMNS_READ; + DBUG_PRINT("info", ("thd->column_usage: %d", thd->column_usage)); + select_lex->cond_count= 0; + select_lex->between_count= 0; + select_lex->max_equal_elems= 0; + + for (table= tables; table; table= table->next_local) + { + if (select_lex == thd->lex->first_select_lex() && + select_lex->first_cond_optimization && + table->merged_for_insert && + table->prepare_where(thd, conds, FALSE)) + goto err_no_arena; + } + + if (*conds) + { + thd->where="where clause"; + DBUG_EXECUTE("where", + print_where(*conds, + "WHERE in setup_conds", + QT_ORDINARY);); + /* + Wrap alone field in WHERE clause in case it will be outer field of subquery + which need persistent pointer on it, but conds could be changed by optimizer + */ + if ((*conds)->type() == Item::FIELD_ITEM && !derived) + wrap_ident(thd, conds); + (*conds)->mark_as_condition_AND_part(NO_JOIN_NEST); + if ((*conds)->fix_fields_if_needed_for_bool(thd, conds)) + goto err_no_arena; + } + + /* + Apply fix_fields() to all ON clauses at all levels of nesting, + including the ones inside view definitions. + */ + if (setup_on_expr(thd, tables, it_is_update)) + goto err_no_arena; + + if (!thd->stmt_arena->is_conventional()) + { + /* + We are in prepared statement preparation code => we should store + WHERE clause changing for next executions. + + We do this ON -> WHERE transformation only once per PS/SP statement. + */ + select_lex->where= *conds; + } + thd->lex->current_select->is_item_list_lookup= save_is_item_list_lookup; + DBUG_RETURN(MY_TEST(thd->is_error())); + +err_no_arena: + select_lex->is_item_list_lookup= save_is_item_list_lookup; + DBUG_RETURN(1); +} + + +/****************************************************************************** +** Fill a record with data (for INSERT or UPDATE) +** Returns : 1 if some field has wrong type +******************************************************************************/ + + +/** + Fill the fields of a table with the values of an Item list + + @param thd thread handler + @param table_arg the table that is being modified + @param fields Item_fields list to be filled + @param values values to fill with + @param ignore_errors TRUE if we should ignore errors + @param update TRUE if update query + + @details + fill_record() may set table->auto_increment_field_not_null and a + caller should make sure that it is reset after their last call to this + function. + default functions are executed for inserts. + virtual fields are always updated + + @return Status + @retval true An error occurred. + @retval false OK. +*/ + +bool +fill_record(THD *thd, TABLE *table_arg, List<Item> &fields, List<Item> &values, + bool ignore_errors, bool update) +{ + List_iterator_fast<Item> f(fields),v(values); + Item *value, *fld; + Item_field *field; + Field *rfield; + TABLE *table; + bool only_unvers_fields= update && table_arg->versioned(); + bool save_abort_on_warning= thd->abort_on_warning; + bool save_no_errors= thd->no_errors; + DBUG_ENTER("fill_record"); + + thd->no_errors= ignore_errors; + /* + Reset the table->auto_increment_field_not_null as it is valid for + only one row. + */ + if (fields.elements) + table_arg->auto_increment_field_not_null= FALSE; + + while ((fld= f++)) + { + if (!(field= fld->field_for_view_update())) + { + my_error(ER_NONUPDATEABLE_COLUMN, MYF(0), fld->name.str); + goto err; + } + value=v++; + DBUG_ASSERT(value); + rfield= field->field; + table= rfield->table; + if (table->next_number_field && + rfield->field_index == table->next_number_field->field_index) + table->auto_increment_field_not_null= TRUE; + const bool skip_sys_field= rfield->vers_sys_field(); // TODO: && !thd->vers_modify_history() [MDEV-16546] + if ((rfield->vcol_info || skip_sys_field) && + !value->vcol_assignment_allowed_value() && + table->s->table_category != TABLE_CATEGORY_TEMPORARY) + { + push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN, + ER_WARNING_NON_DEFAULT_VALUE_FOR_GENERATED_COLUMN, + ER_THD(thd, ER_WARNING_NON_DEFAULT_VALUE_FOR_GENERATED_COLUMN), + rfield->field_name.str, table->s->table_name.str); + } + if (only_unvers_fields && !rfield->vers_update_unversioned()) + only_unvers_fields= false; + + if (rfield->stored_in_db()) + { + if (!skip_sys_field && + unlikely(value->save_in_field(rfield, 0) < 0) && !ignore_errors) + { + my_message(ER_UNKNOWN_ERROR, ER_THD(thd, ER_UNKNOWN_ERROR), MYF(0)); + goto err; + } + /* + In sql MODE_SIMULTANEOUS_ASSIGNMENT, + move field pointer on value stored in record[1] + which contains row before update (see MDEV-13417) + */ + if (update && thd->variables.sql_mode & MODE_SIMULTANEOUS_ASSIGNMENT) + rfield->move_field_offset((my_ptrdiff_t) (table->record[1] - + table->record[0])); + } + rfield->set_has_explicit_value(); + } + + if (update && thd->variables.sql_mode & MODE_SIMULTANEOUS_ASSIGNMENT) + { + // restore fields pointers on record[0] + f.rewind(); + while ((fld= f++)) + { + rfield= fld->field_for_view_update()->field; + if (rfield->stored_in_db()) + { + table= rfield->table; + rfield->move_field_offset((my_ptrdiff_t) (table->record[0] - + table->record[1])); + } + } + } + + if (update) + table_arg->evaluate_update_default_function(); + else + if (table_arg->default_field && + table_arg->update_default_fields(ignore_errors)) + goto err; + + if (table_arg->versioned() && !only_unvers_fields) + table_arg->vers_update_fields(); + /* Update virtual fields */ + if (table_arg->vfield && + table_arg->update_virtual_fields(table_arg->file, VCOL_UPDATE_FOR_WRITE)) + goto err; + thd->abort_on_warning= save_abort_on_warning; + thd->no_errors= save_no_errors; + DBUG_RETURN(thd->is_error()); +err: + DBUG_PRINT("error",("got error")); + thd->abort_on_warning= save_abort_on_warning; + thd->no_errors= save_no_errors; + if (fields.elements) + table_arg->auto_increment_field_not_null= FALSE; + DBUG_RETURN(TRUE); +} + + +/** + Prepare Item_field's for fill_record_n_invoke_before_triggers() + + This means redirecting from table->field to + table->field_to_fill(), if needed. +*/ +void switch_to_nullable_trigger_fields(List<Item> &items, TABLE *table) +{ + Field** field= table->field_to_fill(); + + /* True if we have NOT NULL fields and BEFORE triggers */ + if (field != table->field) + { + List_iterator_fast<Item> it(items); + Item *item; + + while ((item= it++)) + item->walk(&Item::switch_to_nullable_fields_processor, 1, field); + table->triggers->reset_extra_null_bitmap(); + } +} + + +/** + Prepare Virtual fields and field with default expressions to use + trigger fields + + This means redirecting from table->field to + table->field_to_fill(), if needed. +*/ + +void switch_defaults_to_nullable_trigger_fields(TABLE *table) +{ + if (!table->default_field) + return; // no defaults + + Field **trigger_field= table->field_to_fill(); + + /* True if we have NOT NULL fields and BEFORE triggers */ + if (*trigger_field != *table->field) + { + for (Field **field_ptr= table->default_field; *field_ptr ; field_ptr++) + { + Field *field= (*field_ptr); + field->default_value->expr->walk(&Item::switch_to_nullable_fields_processor, 1, trigger_field); + *field_ptr= (trigger_field[field->field_index]); + } + } +} + + +/** + Test NOT NULL constraint after BEFORE triggers +*/ +static bool not_null_fields_have_null_values(TABLE *table) +{ + Field **orig_field= table->field; + Field **filled_field= table->field_to_fill(); + + if (filled_field != orig_field) + { + THD *thd=table->in_use; + for (uint i=0; i < table->s->fields; i++) + { + Field *of= orig_field[i]; + Field *ff= filled_field[i]; + if (ff != of) + { + // copy after-update flags to of, copy before-update flags to ff + swap_variables(uint32, of->flags, ff->flags); + if (ff->is_real_null()) + { + ff->set_notnull(); // for next row WHERE condition in UPDATE + if (convert_null_to_field_value_or_error(of) || thd->is_error()) + return true; + } + } + } + } + + return false; +} + +/** + Fill fields in list with values from the list of items and invoke + before triggers. + + @param thd thread context + @param table the table that is being modified + @param fields Item_fields list to be filled + @param values values to fill with + @param ignore_errors TRUE if we should ignore errors + @param event event type for triggers to be invoked + + @detail + This function assumes that fields which values will be set and triggers + to be invoked belong to the same table, and that TABLE::record[0] and + record[1] buffers correspond to new and old versions of row respectively. + + @return Status + @retval true An error occurred. + @retval false OK. +*/ + +bool +fill_record_n_invoke_before_triggers(THD *thd, TABLE *table, + List<Item> &fields, + List<Item> &values, bool ignore_errors, + enum trg_event_type event) +{ + int result; + Table_triggers_list *triggers= table->triggers; + + result= fill_record(thd, table, fields, values, ignore_errors, + event == TRG_EVENT_UPDATE); + + if (!result && triggers) + { + if (triggers->process_triggers(thd, event, TRG_ACTION_BEFORE, + TRUE) || + not_null_fields_have_null_values(table)) + return TRUE; + + /* + Re-calculate virtual fields to cater for cases when base columns are + updated by the triggers. + */ + if (table->vfield && fields.elements) + { + Item *fld= (Item_field*) fields.head(); + Item_field *item_field= fld->field_for_view_update(); + if (item_field) + { + DBUG_ASSERT(table == item_field->field->table); + result|= table->update_virtual_fields(table->file, + VCOL_UPDATE_FOR_WRITE); + } + } + } + return result; +} + + +/** + Fill the field buffer of a table with the values of an Item list + All fields are given a value + + @param thd thread handler + @param table_arg the table that is being modified + @param ptr pointer on pointer to record of fields + @param values values to fill with + @param ignore_errors TRUE if we should ignore errors + @param use_value forces usage of value of the items instead of result + + @details + fill_record() may set table->auto_increment_field_not_null and a + caller should make sure that it is reset after their last call to this + function. + + @return Status + @retval true An error occurred. + @retval false OK. +*/ + +bool +fill_record(THD *thd, TABLE *table, Field **ptr, List<Item> &values, + bool ignore_errors, bool use_value) +{ + List_iterator_fast<Item> v(values); + List<TABLE> tbl_list; + Item *value; + Field *field; + bool abort_on_warning_saved= thd->abort_on_warning; + uint autoinc_index= table->next_number_field + ? table->next_number_field->field_index + : ~0U; + DBUG_ENTER("fill_record"); + if (!*ptr) + { + /* No fields to update, quite strange!*/ + DBUG_RETURN(0); + } + + /* + On INSERT or UPDATE fields are checked to be from the same table, + thus we safely can take table from the first field. + */ + DBUG_ASSERT((*ptr)->table == table); + + /* + Reset the table->auto_increment_field_not_null as it is valid for + only one row. + */ + table->auto_increment_field_not_null= FALSE; + while ((field = *ptr++) && ! thd->is_error()) + { + /* Ensure that all fields are from the same table */ + DBUG_ASSERT(field->table == table); + + if (unlikely(field->invisible)) + continue; + + value=v++; + + bool vers_sys_field= table->versioned() && field->vers_sys_field(); + + if (field->field_index == autoinc_index) + table->auto_increment_field_not_null= TRUE; + if ((unlikely(field->vcol_info) || (vers_sys_field && !ignore_errors)) && + !value->vcol_assignment_allowed_value() && + table->s->table_category != TABLE_CATEGORY_TEMPORARY) + { + push_warning_printf(thd, Sql_condition::WARN_LEVEL_WARN, + ER_WARNING_NON_DEFAULT_VALUE_FOR_GENERATED_COLUMN, + ER_THD(thd, ER_WARNING_NON_DEFAULT_VALUE_FOR_GENERATED_COLUMN), + field->field_name.str, table->s->table_name.str); + if (vers_sys_field) + continue; + } + + if (use_value) + value->save_val(field); + else + if (value->save_in_field(field, 0) < 0) + goto err; + field->set_has_explicit_value(); + } + /* Update virtual fields if there wasn't any errors */ + if (!thd->is_error()) + { + thd->abort_on_warning= FALSE; + if (table->versioned()) + table->vers_update_fields(); + if (table->vfield && + table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_WRITE)) + goto err; + thd->abort_on_warning= abort_on_warning_saved; + } + DBUG_RETURN(thd->is_error()); + +err: + thd->abort_on_warning= abort_on_warning_saved; + table->auto_increment_field_not_null= FALSE; + DBUG_RETURN(TRUE); +} + + +/* + Fill fields in an array with values from the list of items and invoke + before triggers. + + @param thd thread context + @param table the table that is being modified + @param ptr the fields to be filled + @param values values to fill with + @param ignore_errors TRUE if we should ignore errors + @param event event type for triggers to be invoked + + @detail + This function assumes that fields which values will be set and triggers + to be invoked belong to the same table, and that TABLE::record[0] and + record[1] buffers correspond to new and old versions of row respectively. + + @return Status + @retval true An error occurred. + @retval false OK. +*/ + +bool +fill_record_n_invoke_before_triggers(THD *thd, TABLE *table, Field **ptr, + List<Item> &values, bool ignore_errors, + enum trg_event_type event) +{ + bool result; + Table_triggers_list *triggers= table->triggers; + + result= fill_record(thd, table, ptr, values, ignore_errors, FALSE); + + if (!result && triggers && *ptr) + result= triggers->process_triggers(thd, event, TRG_ACTION_BEFORE, TRUE) || + not_null_fields_have_null_values(table); + /* + Re-calculate virtual fields to cater for cases when base columns are + updated by the triggers. + */ + if (!result && triggers && *ptr) + { + DBUG_ASSERT(table == (*ptr)->table); + if (table->vfield) + result= table->update_virtual_fields(table->file, VCOL_UPDATE_FOR_WRITE); + } + return result; + +} + + +my_bool mysql_rm_tmp_tables(void) +{ + uint i, idx; + char path[FN_REFLEN], *tmpdir, path_copy[FN_REFLEN]; + MY_DIR *dirp; + FILEINFO *file; + TABLE_SHARE share; + THD *thd; + DBUG_ENTER("mysql_rm_tmp_tables"); + + if (!(thd= new THD(0))) + DBUG_RETURN(1); + thd->thread_stack= (char*) &thd; + thd->store_globals(); + + for (i=0; i<=mysql_tmpdir_list.max; i++) + { + tmpdir=mysql_tmpdir_list.list[i]; + /* See if the directory exists */ + if (!(dirp = my_dir(tmpdir,MYF(MY_WME | MY_DONT_SORT)))) + continue; + + /* Remove all SQLxxx tables from directory */ + + for (idx=0 ; idx < (uint) dirp->number_of_files ; idx++) + { + file=dirp->dir_entry+idx; + + if (!strncmp(file->name, tmp_file_prefix, tmp_file_prefix_length)) + { + char *ext= fn_ext(file->name); + size_t ext_len= strlen(ext); + size_t path_len= my_snprintf(path, sizeof(path), + "%s%c%s", tmpdir, FN_LIBCHAR, + file->name); + if (!strcmp(reg_ext, ext)) + { + /* We should cut file extention before deleting of table */ + memcpy(path_copy, path, path_len - ext_len); + path_copy[path_len - ext_len]= 0; + init_tmp_table_share(thd, &share, "", 0, "", path_copy); + if (!open_table_def(thd, &share)) + share.db_type()->drop_table(share.db_type(), path_copy); + free_table_share(&share); + } + /* + File can be already deleted by tmp_table.file->delete_table(). + So we hide error messages which happnes during deleting of these + files(MYF(0)). + */ + (void) mysql_file_delete(key_file_misc, path, MYF(0)); + } + } + my_dirend(dirp); + } + delete thd; + DBUG_RETURN(0); +} + + +/***************************************************************************** + unireg support functions +*****************************************************************************/ + +int setup_ftfuncs(SELECT_LEX *select_lex) +{ + List_iterator<Item_func_match> li(*(select_lex->ftfunc_list)), + lj(*(select_lex->ftfunc_list)); + Item_func_match *ftf, *ftf2; + + while ((ftf=li++)) + { + if (ftf->fix_index()) + return 1; + lj.rewind(); + while ((ftf2=lj++) != ftf) + { + if (ftf->eq(ftf2,1) && !ftf2->master) + ftf2->master=ftf; + } + } + + return 0; +} + + +void cleanup_ftfuncs(SELECT_LEX *select_lex) +{ + List_iterator<Item_func_match> li(*(select_lex->ftfunc_list)), + lj(*(select_lex->ftfunc_list)); + Item_func_match *ftf; + + while ((ftf=li++)) + { + ftf->cleanup(); + } +} + + +int init_ftfuncs(THD *thd, SELECT_LEX *select_lex, bool no_order) +{ + if (select_lex->ftfunc_list->elements) + { + List_iterator<Item_func_match> li(*(select_lex->ftfunc_list)); + Item_func_match *ifm; + + while ((ifm=li++)) + if (unlikely(!ifm->is_fixed())) + /* + it mean that clause where was FT function was removed, so we have + to remove the function from the list. + */ + li.remove(); + else if (ifm->init_search(thd, no_order)) + return 1; + } + return 0; +} + + +bool is_equal(const LEX_CSTRING *a, const LEX_CSTRING *b) +{ + return a->length == b->length && !strncmp(a->str, b->str, a->length); +} + +/* + Open and lock system tables for read. + + SYNOPSIS + open_system_tables_for_read() + thd Thread context. + table_list List of tables to open. + + NOTES + Caller should have used start_new_trans object to start a new + transcation when reading system tables. + + Thanks to restrictions which we put on opening and locking of + system tables for writing, we can open and lock them for reading + even when we already have some other tables open and locked. + One should call thd->commit_whole_transaction_and_close_tables() + to close systems tables opened with this call. + + NOTES + In some situations we use this function to open system tables for + writing. It happens, for examples, with statistical tables when + they are updated by an ANALYZE command. In these cases we should + guarantee that system tables will not be deadlocked. + + RETURN + FALSE Success + TRUE Error +*/ + +bool +open_system_tables_for_read(THD *thd, TABLE_LIST *table_list) +{ + Query_tables_list query_tables_list_backup; + LEX *lex= thd->lex; + DBUG_ENTER("open_system_tables_for_read"); + DBUG_ASSERT(thd->internal_transaction()); + + /* + Besides using new Open_tables_state for opening system tables, + we also have to backup and reset/and then restore part of LEX + which is accessed by open_tables() in order to determine if + prelocking is needed and what tables should be added for it. + */ + lex->reset_n_backup_query_tables_list(&query_tables_list_backup); + thd->lex->sql_command= SQLCOM_SELECT; + + /* + Only use MYSQL_LOCK_IGNORE_TIMEOUT for tables opened for read. + This is to ensure that lock_wait_timeout is honored when trying + to update stats tables. + */ + if (open_and_lock_tables(thd, table_list, FALSE, + (MYSQL_OPEN_IGNORE_FLUSH | + MYSQL_OPEN_IGNORE_LOGGING_FORMAT | + (table_list->lock_type < TL_WRITE_ALLOW_WRITE ? + MYSQL_LOCK_IGNORE_TIMEOUT : 0)))) + { + lex->restore_backup_query_tables_list(&query_tables_list_backup); + DBUG_RETURN(TRUE); + } + + for (TABLE_LIST *tables= table_list; tables; tables= tables->next_global) + { + DBUG_ASSERT(tables->table->s->table_category == TABLE_CATEGORY_SYSTEM); + tables->table->file->row_logging= 0; + tables->table->use_all_columns(); + } + lex->restore_backup_query_tables_list(&query_tables_list_backup); + + DBUG_RETURN(FALSE); +} + +/** + A helper function to close a mysql.* table opened + in an auxiliary THD during bootstrap or in the main + connection, when we know that there are no locks + held by the connection due to a preceding implicit + commit. + + We need this function since we'd like to not + just close the system table, but also release + the metadata lock on it. + + Note, that in LOCK TABLES mode this function + does not release the metadata lock. But in this + mode the table can be opened only if it is locked + explicitly with LOCK TABLES. +*/ + +void +close_mysql_tables(THD *thd) +{ + if (! thd->in_sub_stmt) + { + trans_commit_stmt(thd); + trans_commit(thd); + } + close_thread_tables(thd); + thd->release_transactional_locks(); +} + +/* + Open and lock one system table for update. + + SYNOPSIS + open_system_table_for_update() + thd Thread context. + one_table Table to open. + + NOTES + Table opened with this call should closed using close_thread_tables(). + + RETURN + 0 Error + # Pointer to TABLE object of system table +*/ + +TABLE * +open_system_table_for_update(THD *thd, TABLE_LIST *one_table) +{ + DBUG_ENTER("open_system_table_for_update"); + + TABLE *table= open_ltable(thd, one_table, one_table->lock_type, + MYSQL_LOCK_IGNORE_TIMEOUT); + if (table) + { + DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_SYSTEM); + table->use_all_columns(); + /* This table instance is not row logged */ + table->file->row_logging= 0; + } + DBUG_RETURN(table); +} + +/** + Open a log table. + Opening such tables is performed internally in the server + implementation, and is a 'nested' open, since some tables + might be already opened by the current thread. + The thread context before this call is saved, and is restored + when calling close_log_table(). + @param thd The current thread + @param one_table Log table to open + @param backup [out] Temporary storage used to save the thread context +*/ +TABLE * +open_log_table(THD *thd, TABLE_LIST *one_table, Open_tables_backup *backup) +{ + uint flags= ( MYSQL_OPEN_IGNORE_GLOBAL_READ_LOCK | + MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY | + MYSQL_OPEN_IGNORE_FLUSH | + MYSQL_LOCK_IGNORE_TIMEOUT | + MYSQL_LOCK_LOG_TABLE); + TABLE *table; + /* Save value that is changed in mysql_lock_tables() */ + ulonglong save_utime_after_lock= thd->utime_after_lock; + DBUG_ENTER("open_log_table"); + + thd->reset_n_backup_open_tables_state(backup); + + if ((table= open_ltable(thd, one_table, one_table->lock_type, flags))) + { + DBUG_ASSERT(table->s->table_category == TABLE_CATEGORY_LOG); + DBUG_ASSERT(!table->file->row_logging); + + /* Make sure all columns get assigned to a default value */ + table->use_all_columns(); + DBUG_ASSERT(table->s->no_replicate); + } + else + thd->restore_backup_open_tables_state(backup); + + thd->utime_after_lock= save_utime_after_lock; + DBUG_RETURN(table); +} + +/** + Close a log table. + The last table opened by open_log_table() + is closed, then the thread context is restored. + @param thd The current thread + @param backup [in] the context to restore. +*/ + +void close_log_table(THD *thd, Open_tables_backup *backup) +{ + /* + Inform the transaction handler that we are closing the + system tables and we don't need the read view anymore. + */ + for (TABLE *table= thd->open_tables ; table ; table= table->next) + table->file->extra(HA_EXTRA_PREPARE_FOR_FORCED_CLOSE); + close_thread_tables(thd); + thd->restore_backup_open_tables_state(backup); +} + + +/** + @brief + Remove 'fixed' flag from items in a list + + @param items list of items to un-fix + + @details + This function sets to 0 the 'fixed' flag for items in the 'items' list. + It's needed to force correct marking of views' fields for INSERT/UPDATE + statements. +*/ + +void unfix_fields(List<Item> &fields) +{ + List_iterator<Item> li(fields); + Item *item; + while ((item= li++)) + item->unfix_fields(); +} + + +/** + Check result of dynamic column function and issue error if it is needed + + @param rc The result code of dynamic column function + + @return the result code which was get as an argument\ +*/ + +int dynamic_column_error_message(enum_dyncol_func_result rc) +{ + switch (rc) { + case ER_DYNCOL_YES: + case ER_DYNCOL_OK: + case ER_DYNCOL_TRUNCATED: + break; // it is not an error + case ER_DYNCOL_FORMAT: + my_error(ER_DYN_COL_WRONG_FORMAT, MYF(0)); + break; + case ER_DYNCOL_LIMIT: + my_error(ER_DYN_COL_IMPLEMENTATION_LIMIT, MYF(0)); + break; + case ER_DYNCOL_RESOURCE: + my_error(ER_OUT_OF_RESOURCES, MYF(0)); + break; + case ER_DYNCOL_DATA: + my_error(ER_DYN_COL_DATA, MYF(0)); + break; + case ER_DYNCOL_UNKNOWN_CHARSET: + my_error(ER_DYN_COL_WRONG_CHARSET, MYF(0)); + break; + } + return rc; +} + + +/** + Turn on the SELECT_DESCRIBE flag for the primary SELECT_LEX of the statement + being processed in case the statement is EXPLAIN UPDATE/DELETE. + + @param lex current LEX +*/ + +void promote_select_describe_flag_if_needed(LEX *lex) +{ + if (lex->describe) + lex->first_select_lex()->options|= SELECT_DESCRIBE; +} + + +/** + @} (end of group Data_Dictionary) +*/ |