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Diffstat (limited to 'sql/events.cc')
| -rw-r--r-- | sql/events.cc | 1327 |
1 files changed, 1327 insertions, 0 deletions
diff --git a/sql/events.cc b/sql/events.cc new file mode 100644 index 00000000..64ff2642 --- /dev/null +++ b/sql/events.cc @@ -0,0 +1,1327 @@ +/* + Copyright (c) 2005, 2013, Oracle and/or its affiliates. + Copyright (c) 2017, 2020, MariaDB Corporation. + + 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 St, Fifth Floor, Boston, MA 02110-1335 USA */ + +#include "mariadb.h" +#include "sql_priv.h" +#include "unireg.h" +#include "sql_parse.h" // check_access +#include "sql_base.h" // close_mysql_tables +#include "sql_show.h" // append_definer +#include "events.h" +#include "sql_db.h" // check_db_dir_existence +#include "sql_table.h" // write_bin_log +#include "tztime.h" // struct Time_zone +#include "sql_acl.h" // EVENT_ACL +#include "records.h" // init_read_record, end_read_record +#include "event_data_objects.h" +#include "event_db_repository.h" +#include "event_queue.h" +#include "event_scheduler.h" +#include "sp_head.h" // for Stored_program_creation_ctx +#include "set_var.h" +#include "lock.h" // lock_object_name +#include "mysql/psi/mysql_sp.h" +#include "wsrep_mysqld.h" + +/** + @addtogroup Event_Scheduler + @{ +*/ + +/* + TODO list : + - CREATE EVENT should not go into binary log! Does it now? The SQL statements + issued by the EVENT are replicated. + I have an idea how to solve the problem at failover. So the status field + will be ENUM('DISABLED', 'ENABLED', 'SLAVESIDE_DISABLED'). + In this case when CREATE EVENT is replicated it should go into the binary + as SLAVESIDE_DISABLED if it is ENABLED, when it's created as DISABLEd it + should be replicated as disabled. If an event is ALTERed as DISABLED the + query should go untouched into the binary log, when ALTERed as enable then + it should go as SLAVESIDE_DISABLED. This is regarding the SQL interface. + TT routines however modify mysql.event internally and this does not go the + log so in this case queries has to be injected into the log...somehow... or + maybe a solution is RBR for this case, because the event may go only from + ENABLED to DISABLED status change and this is safe for replicating. As well + an event may be deleted which is also safe for RBR. + + - Add logging to file + +*/ + + +/* + If the user (un)intentionally removes an event directly from mysql.event + the following sequence has to be used to be able to remove the in-memory + counterpart. + 1. CREATE EVENT the_name ON SCHEDULE EVERY 1 SECOND DISABLE DO SELECT 1; + 2. DROP EVENT the_name + + In other words, the first one will create a row in mysql.event . In the + second step because there will be a line, disk based drop will pass and + the scheduler will remove the memory counterpart. The reason is that + in-memory queue does not check whether the event we try to drop from memory + is disabled. Disabled events are not kept in-memory because they are not + eligible for execution. +*/ + +Event_queue *Events::event_queue; +Event_scheduler *Events::scheduler; +Event_db_repository *Events::db_repository; +ulong Events::opt_event_scheduler= Events::EVENTS_OFF; +ulong Events::startup_state= Events::EVENTS_OFF; +ulong Events::inited; + + +/* + Compares 2 LEX strings regarding case. + + SYNOPSIS + sortcmp_lex_string() + s First LEX_STRING + t Second LEX_STRING + cs Charset + + RETURN VALUE + -1 s < t + 0 s == t + 1 s > t +*/ + +int sortcmp_lex_string(const LEX_CSTRING *s, const LEX_CSTRING *t, + const CHARSET_INFO *cs) +{ + return cs->strnncollsp(s->str, s->length, + t->str, t->length); +} + + +/** + Push an error into the error stack if the system tables are + not up to date. +*/ + +bool Events::check_if_system_tables_error() +{ + DBUG_ENTER("Events::check_if_system_tables_error"); + + if (!inited) + { + my_error(ER_EVENTS_DB_ERROR, MYF(0)); + DBUG_RETURN(TRUE); + } + + DBUG_RETURN(FALSE); +} + + +/** + Reconstructs interval expression from interval type and expression + value that is in form of a value of the smallest entity: + For + YEAR_MONTH - expression is in months + DAY_MINUTE - expression is in minutes + + SYNOPSIS + Events::reconstruct_interval_expression() + buf Preallocated String buffer to add the value to + interval The interval type (for instance YEAR_MONTH) + expression The value in the lowest entity + + RETURN VALUE + 0 OK + 1 Error +*/ + +int +Events::reconstruct_interval_expression(String *buf, interval_type interval, + longlong expression) +{ + ulonglong expr= expression; + char tmp_buff[128], *end; + bool close_quote= TRUE; + int multipl= 0; + char separator=':'; + + switch (interval) { + case INTERVAL_YEAR_MONTH: + multipl= 12; + separator= '-'; + goto common_1_lev_code; + case INTERVAL_DAY_HOUR: + multipl= 24; + separator= ' '; + goto common_1_lev_code; + case INTERVAL_HOUR_MINUTE: + case INTERVAL_MINUTE_SECOND: + multipl= 60; +common_1_lev_code: + buf->append('\''); + end= longlong10_to_str(expression/multipl, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff)); + expr= expr - (expr/multipl)*multipl; + break; + case INTERVAL_DAY_MINUTE: + { + ulonglong tmp_expr= expr; + + tmp_expr/=(24*60); + buf->append('\''); + end= longlong10_to_str(tmp_expr, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// days + buf->append(' '); + + tmp_expr= expr - tmp_expr*(24*60);//minutes left + end= longlong10_to_str(tmp_expr/60, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// hours + + expr= tmp_expr - (tmp_expr/60)*60; + /* the code after the switch will finish */ + break; + } + case INTERVAL_HOUR_SECOND: + { + ulonglong tmp_expr= expr; + + buf->append('\''); + end= longlong10_to_str(tmp_expr/3600, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// hours + buf->append(':'); + + tmp_expr= tmp_expr - (tmp_expr/3600)*3600; + end= longlong10_to_str(tmp_expr/60, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// minutes + + expr= tmp_expr - (tmp_expr/60)*60; + /* the code after the switch will finish */ + break; + } + case INTERVAL_DAY_SECOND: + { + ulonglong tmp_expr= expr; + + tmp_expr/=(24*3600); + buf->append('\''); + end= longlong10_to_str(tmp_expr, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// days + buf->append(' '); + + tmp_expr= expr - tmp_expr*(24*3600);//seconds left + end= longlong10_to_str(tmp_expr/3600, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// hours + buf->append(':'); + + tmp_expr= tmp_expr - (tmp_expr/3600)*3600; + end= longlong10_to_str(tmp_expr/60, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff));// minutes + + expr= tmp_expr - (tmp_expr/60)*60; + /* the code after the switch will finish */ + break; + } + case INTERVAL_DAY_MICROSECOND: + case INTERVAL_HOUR_MICROSECOND: + case INTERVAL_MINUTE_MICROSECOND: + case INTERVAL_SECOND_MICROSECOND: + case INTERVAL_MICROSECOND: + my_error(ER_NOT_SUPPORTED_YET, MYF(0), "MICROSECOND"); + return 1; + case INTERVAL_QUARTER: + expr/= 3; + close_quote= FALSE; + break; + case INTERVAL_WEEK: + expr/= 7; + close_quote= FALSE; + break; + default: + close_quote= FALSE; + break; + } + if (close_quote) + buf->append(separator); + end= longlong10_to_str(expr, tmp_buff, 10); + buf->append(tmp_buff, (uint) (end- tmp_buff)); + if (close_quote) + buf->append('\''); + + return 0; +} + + +/** + Create a new query string for removing executable comments + for avoiding leak and keeping consistency of the execution + on master and slave. + + @param[in] thd Thread handler + @param[in] buf Query string + + @return + 0 ok + 1 error +*/ +static int +create_query_string(THD *thd, String *buf) +{ + buf->length(0); + /* Append the "CREATE" part of the query */ + if (thd->lex->create_info.or_replace()) + { + if (buf->append(STRING_WITH_LEN("CREATE OR REPLACE "))) + return 1; + } + else if (buf->append(STRING_WITH_LEN("CREATE "))) + return 1; + /* Append definer */ + append_definer(thd, buf, &(thd->lex->definer->user), &(thd->lex->definer->host)); + /* Append the left part of thd->query after "DEFINER" part */ + if (buf->append(thd->lex->stmt_definition_begin, + thd->lex->stmt_definition_end - + thd->lex->stmt_definition_begin)) + return 1; + + return 0; +} + + +/** + Create a new event. + + @param[in,out] thd THD + @param[in] parse_data Event's data from parsing stage + + In case there is an event with the same name (db) and + IF NOT EXISTS is specified, an warning is put into the stack. + @sa Events::drop_event for the notes about locking, pre-locking + and Events DDL. + + @retval FALSE OK + @retval TRUE Error (reported) +*/ + +bool +Events::create_event(THD *thd, Event_parse_data *parse_data) +{ + bool ret; + bool event_already_exists; + enum_binlog_format save_binlog_format; + DBUG_ENTER("Events::create_event"); + + if (unlikely(check_if_system_tables_error())) + DBUG_RETURN(TRUE); + + /* + Perform semantic checks outside of Event_db_repository: + once CREATE EVENT is supported in prepared statements, the + checks will be moved to PREPARE phase. + */ + if (parse_data->check_parse_data(thd)) + DBUG_RETURN(TRUE); + + /* At create, one of them must be set */ + DBUG_ASSERT(parse_data->expression || parse_data->execute_at); + + if (check_access(thd, EVENT_ACL, parse_data->dbname.str, NULL, NULL, 0, 0)) + DBUG_RETURN(TRUE); + WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL); + + if (lock_object_name(thd, MDL_key::EVENT, + parse_data->dbname.str, parse_data->name.str)) + DBUG_RETURN(TRUE); + + if (check_db_dir_existence(parse_data->dbname.str)) + { + my_error(ER_BAD_DB_ERROR, MYF(0), parse_data->dbname.str); + DBUG_RETURN(TRUE); + } + + if (parse_data->do_not_create) + DBUG_RETURN(FALSE); + /* + Turn off row binlogging of this statement and use statement-based + so that all supporting tables are updated for CREATE EVENT command. + */ + save_binlog_format= thd->set_current_stmt_binlog_format_stmt(); + + if (thd->lex->create_info.or_replace() && event_queue) + event_queue->drop_event(thd, &parse_data->dbname, &parse_data->name); + + /* On error conditions my_error() is called so no need to handle here */ + if (!(ret= db_repository->create_event(thd, parse_data, + &event_already_exists))) + { + Event_queue_element *new_element; + bool dropped= 0; + + if (!event_already_exists) + { + if (!(new_element= new Event_queue_element())) + ret= TRUE; // OOM + else if ((ret= db_repository->load_named_event(thd, &parse_data->dbname, + &parse_data->name, + new_element))) + { + if (!db_repository->drop_event(thd, &parse_data->dbname, + &parse_data->name, TRUE)) + dropped= 1; + delete new_element; + } + else + { + /* TODO: do not ignore the out parameter and a possible OOM error! */ + bool created; + if (event_queue) + event_queue->create_event(thd, new_element, &created); + } + } + /* + binlog the create event unless it's been successfully dropped + */ + if (!dropped) + { + /* Binlog the create event. */ + DBUG_ASSERT(thd->query() && thd->query_length()); + char buffer[1024]; + String log_query(buffer, sizeof(buffer), &my_charset_bin); + if (create_query_string(thd, &log_query)) + { + my_message_sql(ER_STARTUP, + "Event Error: An error occurred while creating query " + "string, before writing it into binary log.", + MYF(ME_ERROR_LOG)); + ret= true; + } + else + { + /* + If the definer is not set or set to CURRENT_USER, the value + of CURRENT_USER will be written into the binary log as the + definer for the SQL thread. + */ + ret= write_bin_log(thd, TRUE, log_query.ptr(), log_query.length()); + } + } + } + + thd->restore_stmt_binlog_format(save_binlog_format); + + if (!ret && Events::opt_event_scheduler == Events::EVENTS_OFF) + { + push_warning(thd, Sql_condition::WARN_LEVEL_WARN, ER_UNKNOWN_ERROR, + "Event scheduler is switched off, use SET GLOBAL event_scheduler=ON to enable it."); + } + + DBUG_RETURN(ret); +#ifdef WITH_WSREP +wsrep_error_label: + DBUG_RETURN(true); +#endif +} + + +/** + Alter an event. + + @param[in,out] thd THD + @param[in] parse_data Event's data from parsing stage + @param[in] new_dbname A new schema name for the event. Set in the case of + ALTER EVENT RENAME, otherwise is NULL. + @param[in] new_name A new name for the event. Set in the case of + ALTER EVENT RENAME + + Parameter 'et' contains data about dbname and event name. + Parameter 'new_name' is the new name of the event, if not null + this means that RENAME TO was specified in the query + @sa Events::drop_event for the locking notes. + + @retval FALSE OK + @retval TRUE error (reported) +*/ + +bool +Events::update_event(THD *thd, Event_parse_data *parse_data, + LEX_CSTRING *new_dbname, LEX_CSTRING *new_name) +{ + int ret; + enum_binlog_format save_binlog_format; + Event_queue_element *new_element; + + DBUG_ENTER("Events::update_event"); + + if (unlikely(check_if_system_tables_error())) + DBUG_RETURN(TRUE); + + if (parse_data->check_parse_data(thd) || parse_data->do_not_create) + DBUG_RETURN(TRUE); + + if (check_access(thd, EVENT_ACL, parse_data->dbname.str, NULL, NULL, 0, 0)) + DBUG_RETURN(TRUE); + + WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL); + + if (lock_object_name(thd, MDL_key::EVENT, + parse_data->dbname.str, parse_data->name.str)) + DBUG_RETURN(TRUE); + + if (check_db_dir_existence(parse_data->dbname.str)) + { + my_error(ER_BAD_DB_ERROR, MYF(0), parse_data->dbname.str); + DBUG_RETURN(TRUE); + } + + + if (new_dbname) /* It's a rename */ + { + /* Check that the new and the old names differ. */ + if ( !sortcmp_lex_string(&parse_data->dbname, new_dbname, + system_charset_info) && + !sortcmp_lex_string(&parse_data->name, new_name, + system_charset_info)) + { + my_error(ER_EVENT_SAME_NAME, MYF(0)); + DBUG_RETURN(TRUE); + } + + /* + And the user has sufficient privileges to use the target database. + Do it before checking whether the database exists: we don't want + to tell the user that a database doesn't exist if they can not + access it. + */ + if (check_access(thd, EVENT_ACL, new_dbname->str, NULL, NULL, 0, 0)) + DBUG_RETURN(TRUE); + + /* + Acquire mdl exclusive lock on target database name. + */ + if (lock_object_name(thd, MDL_key::EVENT, + new_dbname->str, new_name->str)) + DBUG_RETURN(TRUE); + + /* Check that the target database exists */ + if (check_db_dir_existence(new_dbname->str)) + { + my_error(ER_BAD_DB_ERROR, MYF(0), new_dbname->str); + DBUG_RETURN(TRUE); + } + } + + /* + Turn off row binlogging of this statement and use statement-based + so that all supporting tables are updated for UPDATE EVENT command. + */ + save_binlog_format= thd->set_current_stmt_binlog_format_stmt(); + + /* On error conditions my_error() is called so no need to handle here */ + if (!(ret= db_repository->update_event(thd, parse_data, + new_dbname, new_name))) + { + LEX_CSTRING dbname= new_dbname ? *new_dbname : parse_data->dbname; + LEX_CSTRING name= new_name ? *new_name : parse_data->name; + + if (!(new_element= new Event_queue_element())) + ret= TRUE; // OOM + else if ((ret= db_repository->load_named_event(thd, &dbname, &name, + new_element))) + delete new_element; + else + { + /* + TODO: check if an update actually has inserted an entry + into the queue. + If not, and the element is ON COMPLETION NOT PRESERVE, delete + it right away. + */ + if (event_queue) + event_queue->update_event(thd, &parse_data->dbname, &parse_data->name, + new_element); + /* Binlog the alter event. */ + DBUG_ASSERT(thd->query() && thd->query_length()); + ret= write_bin_log(thd, TRUE, thd->query(), thd->query_length()); + } + } + + thd->restore_stmt_binlog_format(save_binlog_format); + DBUG_RETURN(ret); +#ifdef WITH_WSREP +wsrep_error_label: + DBUG_RETURN(true); +#endif +} + + +/** + Drops an event + + @param[in,out] thd THD + @param[in] dbname Event's schema + @param[in] name Event's name + @param[in] if_exists When this is set and the event does not exist + a warning is pushed into the warning stack. + Otherwise the operation produces an error. + + @note Similarly to DROP PROCEDURE, we do not allow DROP EVENT + under LOCK TABLES mode, unless table mysql.event is locked. To + ensure that, we do not reset & backup the open tables state in + this function - if in LOCK TABLES or pre-locking mode, this will + lead to an error 'Table mysql.event is not locked with LOCK + TABLES' unless it _is_ locked. In pre-locked mode there is + another barrier - DROP EVENT commits the current transaction, + and COMMIT/ROLLBACK is not allowed in stored functions and + triggers. + + @retval FALSE OK + @retval TRUE Error (reported) +*/ + +bool +Events::drop_event(THD *thd, const LEX_CSTRING *dbname, + const LEX_CSTRING *name, bool if_exists) +{ + int ret; + enum_binlog_format save_binlog_format; + DBUG_ENTER("Events::drop_event"); + + if (unlikely(check_if_system_tables_error())) + DBUG_RETURN(TRUE); + + if (check_access(thd, EVENT_ACL, dbname->str, NULL, NULL, 0, 0)) + DBUG_RETURN(TRUE); + + WSREP_TO_ISOLATION_BEGIN(WSREP_MYSQL_DB, NULL, NULL); + + /* + Turn off row binlogging of this statement and use statement-based so + that all supporting tables are updated for DROP EVENT command. + */ + save_binlog_format= thd->set_current_stmt_binlog_format_stmt(); + + if (lock_object_name(thd, MDL_key::EVENT, + dbname->str, name->str)) + DBUG_RETURN(TRUE); + /* On error conditions my_error() is called so no need to handle here */ + if (!(ret= db_repository->drop_event(thd, dbname, name, if_exists))) + { + if (event_queue) + event_queue->drop_event(thd, dbname, name); + /* Binlog the drop event. */ + DBUG_ASSERT(thd->query() && thd->query_length()); + ret= write_bin_log(thd, TRUE, thd->query(), thd->query_length()); + /* Drop statistics for this stored program from performance schema. */ + MYSQL_DROP_SP(SP_TYPE_EVENT, + dbname->str, static_cast<uint>(dbname->length), name->str, static_cast<uint>(name->length)); + } + + thd->restore_stmt_binlog_format(save_binlog_format); + DBUG_RETURN(ret); +#ifdef WITH_WSREP +wsrep_error_label: + DBUG_RETURN(true); +#endif +} + + +/** + Drops all events from a schema + + @note We allow to drop all events in a schema even if the + scheduler is disabled. This is to not produce any warnings + in case of DROP DATABASE and a disabled scheduler. + + @param[in,out] thd Thread + @param[in] db ASCIIZ schema name +*/ + +void +Events::drop_schema_events(THD *thd, const char *db) +{ + const LEX_CSTRING db_lex= { db, strlen(db) }; + + DBUG_ENTER("Events::drop_schema_events"); + DBUG_PRINT("enter", ("dropping events from %s", db)); + + DBUG_SLOW_ASSERT(ok_for_lower_case_names(db)); + + /* + Sic: no check if the scheduler is disabled or system tables + are damaged, as intended. + */ + if (event_queue) + event_queue->drop_schema_events(thd, &db_lex); + if (db_repository) + db_repository->drop_schema_events(thd, &db_lex); + else + { + if ((db_repository= new Event_db_repository)) + { + db_repository->drop_schema_events(thd, &db_lex); + delete db_repository; + db_repository= 0; + } + } + DBUG_VOID_RETURN; +} + + +/** + A helper function to generate SHOW CREATE EVENT output from + a named event +*/ + +static bool +send_show_create_event(THD *thd, Event_timed *et, Protocol *protocol) +{ + char show_str_buf[10 * STRING_BUFFER_USUAL_SIZE]; + String show_str(show_str_buf, sizeof(show_str_buf), system_charset_info); + List<Item> field_list; + LEX_CSTRING sql_mode; + const String *tz_name; + MEM_ROOT *mem_root= thd->mem_root; + DBUG_ENTER("send_show_create_event"); + + show_str.length(0); + if (et->get_create_event(thd, &show_str)) + DBUG_RETURN(TRUE); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "Event", NAME_CHAR_LEN), + mem_root); + + if (sql_mode_string_representation(thd, et->sql_mode, &sql_mode)) + DBUG_RETURN(TRUE); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "sql_mode", + (uint) sql_mode.length), mem_root); + + tz_name= et->time_zone->get_name(); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "time_zone", tz_name->length()), + mem_root); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "Create Event", + show_str.length()), mem_root); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "character_set_client", + MY_CS_CHARACTER_SET_NAME_SIZE), + mem_root); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "collation_connection", + MY_CS_COLLATION_NAME_SIZE), mem_root); + + field_list.push_back(new (mem_root) + Item_empty_string(thd, "Database Collation", + MY_CS_COLLATION_NAME_SIZE), mem_root); + + if (protocol->send_result_set_metadata(&field_list, + Protocol::SEND_NUM_ROWS | Protocol::SEND_EOF)) + DBUG_RETURN(TRUE); + + protocol->prepare_for_resend(); + + protocol->store(et->name.str, et->name.length, system_charset_info); + protocol->store(sql_mode.str, sql_mode.length, system_charset_info); + protocol->store(tz_name->ptr(), tz_name->length(), system_charset_info); + protocol->store(show_str.ptr(), show_str.length(), + et->creation_ctx->get_client_cs()); + protocol->store(&et->creation_ctx->get_client_cs()->cs_name, + system_charset_info); + protocol->store(&et->creation_ctx->get_connection_cl()->coll_name, + system_charset_info); + protocol->store(&et->creation_ctx->get_db_cl()->coll_name, + system_charset_info); + + if (protocol->write()) + DBUG_RETURN(TRUE); + + my_eof(thd); + + DBUG_RETURN(FALSE); +} + + +/** + Implement SHOW CREATE EVENT statement + + thd Thread context + spn The name of the event (db, name) + + @retval FALSE OK + @retval TRUE error (reported) +*/ + +bool +Events::show_create_event(THD *thd, const LEX_CSTRING *dbname, + const LEX_CSTRING *name) +{ + Event_timed et; + bool ret; + + DBUG_ENTER("Events::show_create_event"); + DBUG_PRINT("enter", ("name: %s@%s", dbname->str, name->str)); + + if (unlikely(check_if_system_tables_error())) + DBUG_RETURN(TRUE); + + if (check_access(thd, EVENT_ACL, dbname->str, NULL, NULL, 0, 0)) + DBUG_RETURN(TRUE); + + /* + We would like to allow SHOW CREATE EVENT under LOCK TABLES and + in pre-locked mode. mysql.event table is marked as a system table. + This flag reduces the set of its participation scenarios in LOCK TABLES + operation, and therefore an out-of-bound open of this table + for reading like the one below (sic, only for reading) is + more or less deadlock-free. For additional information about when a + deadlock can occur please refer to the description of 'system table' + flag. + */ + ret= db_repository->load_named_event(thd, dbname, name, &et); + + if (!ret) + ret= send_show_create_event(thd, &et, thd->protocol); + + DBUG_RETURN(ret); +} + + +/** + Check access rights and fill INFORMATION_SCHEMA.events table. + + @param[in,out] thd Thread context + @param[in] tables The temporary table to fill. + + In MySQL INFORMATION_SCHEMA tables are temporary tables that are + created and filled on demand. In this function, we fill + INFORMATION_SCHEMA.events. It is a callback for I_S module, invoked from + sql_show.cc + + @return Has to be integer, as such is the requirement of the I_S API + @retval 0 success + @retval 1 an error, pushed into the error stack +*/ + +int +Events::fill_schema_events(THD *thd, TABLE_LIST *tables, COND * /* cond */) +{ + const char *db= NULL; + int ret; + char db_tmp[SAFE_NAME_LEN]; + DBUG_ENTER("Events::fill_schema_events"); + + /* + If we didn't start events because of --skip-grant-tables, return an + empty set + */ + if (opt_noacl) + DBUG_RETURN(0); + + if (unlikely(check_if_system_tables_error())) + DBUG_RETURN(1); + + /* + If it's SHOW EVENTS then thd->lex->select_lex.db is guaranteed not to + be NULL. Let's do an assert anyway. + */ + if (thd->lex->sql_command == SQLCOM_SHOW_EVENTS) + { + LEX_CSTRING *lexdb= &thd->lex->first_select_lex()->db; + DBUG_ASSERT(lexdb); + if (!is_infoschema_db(lexdb) && !is_perfschema_db(lexdb) && + check_access(thd, EVENT_ACL, lexdb->str, NULL, NULL, 0, 0)) + DBUG_RETURN(1); + db= normalize_db_name(lexdb->str, db_tmp, sizeof(db_tmp)); + } + ret= db_repository->fill_schema_events(thd, tables, db); + + DBUG_RETURN(ret); +} + + +/** + Initializes the scheduler's structures. + + @param THD or null (if called by init) + @param opt_noacl_or_bootstrap + TRUE if there is --skip-grant-tables or --bootstrap + option. In that case we disable the event scheduler. + + @note This function is not synchronized. + + @retval FALSE Perhaps there was an error, and the event scheduler + is disabled. But the error is not fatal and the + server start up can continue. + @retval TRUE Fatal error. Startup must terminate (call unireg_abort()). +*/ + +bool +Events::init(THD *thd, bool opt_noacl_or_bootstrap) +{ + int err_no; + bool res= FALSE; + bool had_thd= thd != 0; + DBUG_ENTER("Events::init"); + + DBUG_ASSERT(inited == 0); + + /* + Was disabled explicitly from the command line + */ + if (opt_event_scheduler == Events::EVENTS_DISABLED || + opt_noacl_or_bootstrap) + DBUG_RETURN(FALSE); + + /* We need a temporary THD during boot */ + if (!thd) + { + + if (!(thd= new THD(0))) + { + res= TRUE; + goto end; + } + /* + The thread stack does not start from this function but we cannot + guess the real value. So better some value that doesn't assert than + no value. + */ + thd->thread_stack= (char*) &thd; + thd->store_globals(); + /* + Set current time for the thread that handles events. + Current time is stored in data member start_time of THD class. + Subsequently, this value is used to check whether event was expired + when make loading events from storage. Check for event expiration time + is done at Event_queue_element::compute_next_execution_time() where + event's status set to Event_parse_data::DISABLED and dropped flag set + to true if event was expired. + */ + thd->set_time(); + } + + /* + We will need Event_db_repository anyway, even if the scheduler is + disabled - to perform events DDL. + */ + DBUG_ASSERT(db_repository == 0); + + if (!(db_repository= new Event_db_repository)) + { + res= TRUE; /* fatal error: request unireg_abort */ + goto end; + } + + /* + Since we allow event DDL even if the scheduler is disabled, + check the system tables, as we might need them. + + If run with --skip-grant-tables or --bootstrap, don't try to do the + check of system tables and don't complain: in these modes the tables + are most likely not there and we're going to disable the event + scheduler anyway. + */ + if (Event_db_repository::check_system_tables(thd)) + { + delete db_repository; + db_repository= 0; + my_message(ER_STARTUP, + "Event Scheduler: An error occurred when initializing " + "system tables. Disabling the Event Scheduler.", + MYF(ME_ERROR_LOG)); + /* Disable the scheduler since the system tables are not up to date */ + opt_event_scheduler= EVENTS_OFF; + goto end; + } + + + DBUG_ASSERT(opt_event_scheduler == Events::EVENTS_ON || + opt_event_scheduler == Events::EVENTS_OFF); + + if (!(event_queue= new Event_queue) || + !(scheduler= new Event_scheduler(event_queue))) + { + res= TRUE; /* fatal error: request unireg_abort */ + goto end; + } + + if (event_queue->init_queue(thd) || load_events_from_db(thd) || + (opt_event_scheduler == EVENTS_ON && scheduler->start(&err_no))) + { + my_message_sql(ER_STARTUP, + "Event Scheduler: Error while loading from mysql.event table.", + MYF(ME_ERROR_LOG)); + res= TRUE; /* fatal error: request unireg_abort */ + goto end; + } + Event_worker_thread::init(db_repository); + inited= 1; + +end: + if (res) + deinit(); + if (!had_thd) + delete thd; + + DBUG_RETURN(res); +} + +/* + Cleans up scheduler's resources. Called at server shutdown. + + SYNOPSIS + Events::deinit() + + NOTES + This function is not synchronized. +*/ + +void +Events::deinit() +{ + DBUG_ENTER("Events::deinit"); + + delete scheduler; + scheduler= NULL; /* For restart */ + delete event_queue; + event_queue= NULL; /* For restart */ + delete db_repository; + db_repository= NULL; /* For restart */ + + inited= 0; + DBUG_VOID_RETURN; +} + +#ifdef HAVE_PSI_INTERFACE +PSI_mutex_key key_LOCK_event_queue, + key_event_scheduler_LOCK_scheduler_state; + +static PSI_mutex_info all_events_mutexes[]= +{ + { &key_LOCK_event_queue, "LOCK_event_queue", PSI_FLAG_GLOBAL}, + { &key_event_scheduler_LOCK_scheduler_state, "Event_scheduler::LOCK_scheduler_state", PSI_FLAG_GLOBAL} +}; + +PSI_cond_key key_event_scheduler_COND_state, key_COND_queue_state; + +static PSI_cond_info all_events_conds[]= +{ + { &key_event_scheduler_COND_state, "Event_scheduler::COND_state", PSI_FLAG_GLOBAL}, + { &key_COND_queue_state, "COND_queue_state", PSI_FLAG_GLOBAL}, +}; + +PSI_thread_key key_thread_event_scheduler, key_thread_event_worker; + +static PSI_thread_info all_events_threads[]= +{ + { &key_thread_event_scheduler, "event_scheduler", PSI_FLAG_GLOBAL}, + { &key_thread_event_worker, "event_worker", 0} +}; +#endif /* HAVE_PSI_INTERFACE */ + +PSI_stage_info stage_waiting_on_empty_queue= { 0, "Waiting on empty queue", 0}; +PSI_stage_info stage_waiting_for_next_activation= { 0, "Waiting for next activation", 0}; +PSI_stage_info stage_waiting_for_scheduler_to_stop= { 0, "Waiting for the scheduler to stop", 0}; + +PSI_memory_key key_memory_event_basic_root; + +#ifdef HAVE_PSI_INTERFACE +PSI_stage_info *all_events_stages[]= +{ + & stage_waiting_on_empty_queue, + & stage_waiting_for_next_activation, + & stage_waiting_for_scheduler_to_stop +}; + +static PSI_memory_info all_events_memory[]= +{ + { &key_memory_event_basic_root, "Event_basic::mem_root", PSI_FLAG_GLOBAL} +}; + +static void init_events_psi_keys(void) +{ + const char* category= "sql"; + int count; + + count= array_elements(all_events_mutexes); + mysql_mutex_register(category, all_events_mutexes, count); + + count= array_elements(all_events_conds); + mysql_cond_register(category, all_events_conds, count); + + count= array_elements(all_events_threads); + mysql_thread_register(category, all_events_threads, count); + + count= array_elements(all_events_stages); + mysql_stage_register(category, all_events_stages, count); + + count= array_elements(all_events_memory); + mysql_memory_register(category, all_events_memory, count); + + init_scheduler_psi_keys(); +} +#endif /* HAVE_PSI_INTERFACE */ + +/** + Inits Events mutexes + + SYNOPSIS + Events::init_mutexes() + thd Thread +*/ + +void +Events::init_mutexes() +{ +#ifdef HAVE_PSI_INTERFACE + init_events_psi_keys(); +#endif +} + + +/* + Dumps the internal status of the scheduler and the memory cache + into a table with two columns - Name & Value. Different properties + which could be useful for debugging for instance deadlocks are + returned. + + SYNOPSIS + Events::dump_internal_status() +*/ + +void +Events::dump_internal_status() +{ + DBUG_ENTER("Events::dump_internal_status"); + puts("\n\n\nEvents status:"); + puts("LLA = Last Locked At LUA = Last Unlocked At"); + puts("WOC = Waiting On Condition DL = Data Locked"); + + /* + opt_event_scheduler should only be accessed while + holding LOCK_global_system_variables. + */ + mysql_mutex_lock(&LOCK_global_system_variables); + if (!inited) + puts("The Event Scheduler is disabled"); + else + { + scheduler->dump_internal_status(); + event_queue->dump_internal_status(); + } + + mysql_mutex_unlock(&LOCK_global_system_variables); + DBUG_VOID_RETURN; +} + +bool Events::start(int *err_no) +{ + DBUG_ASSERT(inited); + return scheduler->start(err_no); +} + +bool Events::stop() +{ + DBUG_ASSERT(inited); + return scheduler->stop(); +} + +/** + Loads all ENABLED events from mysql.event into a prioritized + queue. + + This function is called during the server start up. It reads + every event, computes the next execution time, and if the event + needs execution, adds it to a prioritized queue. Otherwise, if + ON COMPLETION DROP is specified, the event is automatically + removed from the table. + + @param[in,out] thd Thread context. Used for memory allocation in some cases. + + @retval FALSE success + @retval TRUE error, the load is aborted + + @note Reports the error to the console +*/ + +bool +Events::load_events_from_db(THD *thd) +{ + TABLE *table; + READ_RECORD read_record_info; + bool ret= TRUE; + uint count= 0; + DBUG_ENTER("Events::load_events_from_db"); + DBUG_PRINT("enter", ("thd: %p", thd)); + + /* + NOTE: even if we run in read-only mode, we should be able to lock the + mysql.event table for writing. In order to achieve this, we should call + mysql_lock_tables() under the super user. + + Same goes for transaction access mode. + Temporarily reset it to read-write. + */ + + privilege_t saved_master_access(thd->security_ctx->master_access); + thd->security_ctx->master_access |= PRIV_IGNORE_READ_ONLY; + bool save_tx_read_only= thd->tx_read_only; + thd->tx_read_only= false; + + ret= db_repository->open_event_table(thd, TL_WRITE, &table); + + thd->tx_read_only= save_tx_read_only; + thd->security_ctx->master_access= saved_master_access; + + if (ret) + { + my_message_sql(ER_STARTUP, + "Event Scheduler: Failed to open table mysql.event", + MYF(ME_ERROR_LOG)); + DBUG_RETURN(TRUE); + } + + if (init_read_record(&read_record_info, thd, table, NULL, NULL, 0, 1, FALSE)) + { + close_thread_tables(thd); + DBUG_RETURN(TRUE); + } + + while (!(read_record_info.read_record())) + { + Event_queue_element *et; + bool created, dropped; + + if (!(et= new Event_queue_element)) + goto end; + + DBUG_PRINT("info", ("Loading event from row.")); + + if (et->load_from_row(thd, table)) + { + my_message(ER_STARTUP, + "Event Scheduler: " + "Error while loading events from mysql.event. " + "The table probably contains bad data or is corrupted", + MYF(ME_ERROR_LOG)); + delete et; + goto end; + } + +#ifdef WITH_WSREP + /** + If SST is done from a galera node that is also acting as MASTER + newly synced node in galera eco-system will also copy-over the + event state enabling duplicate event in galera eco-system. + DISABLE such events if the current node is not event orginator. + (Also, make sure you skip disabling it if is already disabled to avoid + creation of redundant action) + NOTE: + This complete system relies on server-id. Ideally server-id should be + same for all nodes of galera eco-system but they aren't same. + Infact, based on galera use-case it seems like it recommends to have each + node with different server-id. + */ + if (WSREP(thd) && et->originator != thd->variables.server_id) + { + if (et->status == Event_parse_data::SLAVESIDE_DISABLED) + continue; + + store_record(table, record[1]); + table->field[ET_FIELD_STATUS]-> + store((longlong) Event_parse_data::SLAVESIDE_DISABLED, + TRUE); + + /* All the dmls to mysql.events tables are stmt bin-logged. */ + table->file->row_logging= 0; + (void) table->file->ha_update_row(table->record[1], table->record[0]); + + delete et; + continue; + } +#endif /* WITH_WSREP */ + + /** + Since the Event_queue_element object could be deleted inside + Event_queue::create_event we should save the value of dropped flag + into the temporary variable. + */ + dropped= et->dropped; + if (event_queue->create_event(thd, et, &created)) + { + /* Out of memory */ + delete et; + goto end; + } + if (created) + count++; + else if (dropped) + { + /* + If not created, a stale event - drop if immediately if + ON COMPLETION NOT PRESERVE. + XXX: This won't be replicated, thus the drop won't appear in + in the slave. When the slave is restarted it will drop events. + However, as the slave will be "out of sync", it might happen that + an event created on the master, after master restart, won't be + replicated to the slave correctly, as the create will fail there. + */ + int rc= table->file->ha_delete_row(table->record[0]); + if (rc) + { + table->file->print_error(rc, MYF(0)); + goto end; + } + } + } + my_printf_error(ER_STARTUP, + "Event Scheduler: Loaded %d event%s", + MYF(ME_ERROR_LOG | + (global_system_variables.log_warnings) ? + ME_NOTE: 0), + count, (count == 1) ? "" : "s"); + ret= FALSE; + +end: + end_read_record(&read_record_info); + + close_mysql_tables(thd); + DBUG_RETURN(ret); +} + +#ifdef WITH_WSREP +int wsrep_create_event_query(THD *thd, uchar** buf, size_t* buf_len) +{ + char buffer[1024]; + String log_query(buffer, sizeof(buffer), &my_charset_bin); + + if (create_query_string(thd, &log_query)) + { + WSREP_WARN("events create string failed: schema: %s, query: %s", + thd->get_db(), thd->query()); + return 1; + } + return wsrep_to_buf_helper(thd, log_query.ptr(), log_query.length(), buf, buf_len); +} +#endif /* WITH_WSREP */ +/** + @} (End of group Event_Scheduler) +*/ |