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Diffstat (limited to 'sql/transaction.cc')
| -rw-r--r-- | sql/transaction.cc | 728 |
1 files changed, 728 insertions, 0 deletions
diff --git a/sql/transaction.cc b/sql/transaction.cc new file mode 100644 index 00000000..a6dbf57c --- /dev/null +++ b/sql/transaction.cc @@ -0,0 +1,728 @@ +/* Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved. + Copyright (c) 2009, 2021, 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 Street, Fifth Floor, Boston, MA 02110-1335 USA */ + + +#ifdef USE_PRAGMA_IMPLEMENTATION +#pragma implementation // gcc: Class implementation +#endif + +#include "mariadb.h" +#include "sql_priv.h" +#include "transaction.h" +#include "debug_sync.h" // DEBUG_SYNC +#include "sql_acl.h" +#include "semisync_master.h" +#include <pfs_transaction_provider.h> +#include <mysql/psi/mysql_transaction.h> +#ifdef WITH_WSREP +#include "wsrep_trans_observer.h" +#endif /* WITH_WSREP */ + +/** + Helper: Tell tracker (if any) that transaction ended. +*/ +void trans_track_end_trx(THD *thd) +{ +#ifndef EMBEDDED_LIBRARY + if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) + thd->session_tracker.transaction_info.end_trx(thd); +#endif //EMBEDDED_LIBRARY +} + + +/** + Helper: transaction ended, SET TRANSACTION one-shot variables + revert to session values. Let the transaction state tracker know. +*/ +void trans_reset_one_shot_chistics(THD *thd) +{ +#ifndef EMBEDDED_LIBRARY + if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) + { + thd->session_tracker.transaction_info.set_read_flags(thd, TX_READ_INHERIT); + thd->session_tracker.transaction_info.set_isol_level(thd, TX_ISOL_INHERIT); + } +#endif //EMBEDDED_LIBRARY + thd->tx_isolation= (enum_tx_isolation) thd->variables.tx_isolation; + thd->tx_read_only= thd->variables.tx_read_only; +} + + +/* + Conditions under which the transaction state must not change + + @result TRUE Transaction can not commit + @result FALSE Transaction can commit +*/ + +static bool trans_check(THD *thd) +{ + DBUG_ENTER("trans_check"); + + /* + Always commit statement transaction before manipulating with + the normal one. + */ + DBUG_ASSERT(thd->transaction->stmt.is_empty()); + + if (unlikely(thd->in_sub_stmt)) + { + my_error(ER_COMMIT_NOT_ALLOWED_IN_SF_OR_TRG, MYF(0)); + DBUG_RETURN(TRUE); + } + if (likely(!thd->transaction->xid_state.is_explicit_XA())) + DBUG_RETURN(FALSE); + + thd->transaction->xid_state.er_xaer_rmfail(); + DBUG_RETURN(TRUE); +} + + +/** + Begin a new transaction. + + @note Beginning a transaction implicitly commits any current + transaction and releases existing locks. + + @param thd Current thread + @param flags Transaction flags + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_begin(THD *thd, uint flags) +{ + int res= FALSE; + DBUG_ENTER("trans_begin"); + + if (trans_check(thd)) + DBUG_RETURN(TRUE); + + if (thd->locked_tables_list.unlock_locked_tables(thd)) + DBUG_RETURN(true); + + DBUG_ASSERT(!thd->locked_tables_mode); + + if (thd->in_multi_stmt_transaction_mode() || + (thd->variables.option_bits & OPTION_TABLE_LOCK)) + { + thd->variables.option_bits&= ~OPTION_TABLE_LOCK; + thd->server_status&= + ~(SERVER_STATUS_IN_TRANS | SERVER_STATUS_IN_TRANS_READONLY); + DBUG_PRINT("info", ("clearing SERVER_STATUS_IN_TRANS")); + res= MY_TEST(ha_commit_trans(thd, TRUE)); +#ifdef WITH_WSREP + if (wsrep_thd_is_local(thd)) + { + res= res || wsrep_after_statement(thd); + } +#endif /* WITH_WSREP */ + } + + thd->variables.option_bits&= ~(OPTION_BEGIN | OPTION_BINLOG_THIS_TRX); + + /* + The following set should not be needed as transaction state should + already be reset. We should at some point change this to an assert. + */ + thd->transaction->all.reset(); + thd->has_waiter= false; + thd->waiting_on_group_commit= false; + thd->transaction->start_time.reset(thd); + + if (res) + DBUG_RETURN(TRUE); + + /* + Release transactional metadata locks only after the + transaction has been committed. + */ + thd->release_transactional_locks(); + + // The RO/RW options are mutually exclusive. + DBUG_ASSERT(!((flags & MYSQL_START_TRANS_OPT_READ_ONLY) && + (flags & MYSQL_START_TRANS_OPT_READ_WRITE))); + if (flags & MYSQL_START_TRANS_OPT_READ_ONLY) + { + thd->tx_read_only= true; +#ifndef EMBEDDED_LIBRARY + if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) + thd->session_tracker.transaction_info.set_read_flags(thd, TX_READ_ONLY); +#endif //EMBEDDED_LIBRARY + } + else if (flags & MYSQL_START_TRANS_OPT_READ_WRITE) + { + /* + Explicitly starting a RW transaction when the server is in + read-only mode, is not allowed unless the user has SUPER priv. + Implicitly starting a RW transaction is allowed for backward + compatibility. + */ + const bool user_is_super= + MY_TEST(thd->security_ctx->master_access & PRIV_IGNORE_READ_ONLY); + if (opt_readonly && !user_is_super) + { + my_error(ER_OPTION_PREVENTS_STATEMENT, MYF(0), "--read-only"); + DBUG_RETURN(true); + } + thd->tx_read_only= false; + /* + This flags that tx_read_only was set explicitly, rather than + just from the session's default. + */ +#ifndef EMBEDDED_LIBRARY + if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) + thd->session_tracker.transaction_info.set_read_flags(thd, TX_READ_WRITE); +#endif //EMBEDDED_LIBRARY + } + +#ifdef WITH_WSREP + if (wsrep_thd_is_local(thd)) + { + if (wsrep_sync_wait(thd)) + DBUG_RETURN(TRUE); + if (!thd->tx_read_only && + wsrep_start_transaction(thd, thd->wsrep_next_trx_id())) + DBUG_RETURN(TRUE); + } +#endif /* WITH_WSREP */ + + thd->variables.option_bits|= OPTION_BEGIN; + thd->server_status|= SERVER_STATUS_IN_TRANS; + if (thd->tx_read_only) + thd->server_status|= SERVER_STATUS_IN_TRANS_READONLY; + DBUG_PRINT("info", ("setting SERVER_STATUS_IN_TRANS")); + +#ifndef EMBEDDED_LIBRARY + if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) + thd->session_tracker.transaction_info.add_trx_state(thd, TX_EXPLICIT); +#endif //EMBEDDED_LIBRARY + + /* ha_start_consistent_snapshot() relies on OPTION_BEGIN flag set. */ + if (flags & MYSQL_START_TRANS_OPT_WITH_CONS_SNAPSHOT) + { +#ifndef EMBEDDED_LIBRARY + if (thd->variables.session_track_transaction_info > TX_TRACK_NONE) + thd->session_tracker.transaction_info.add_trx_state(thd, TX_WITH_SNAPSHOT); +#endif //EMBEDDED_LIBRARY + res= ha_start_consistent_snapshot(thd); + } + /* + Register transaction start in performance schema if not done already. + We handle explicitly started transactions here, implicitly started + transactions (and single-statement transactions in autocommit=1 mode) + are handled in trans_register_ha(). + We can't handle explicit transactions in the same way as implicit + because we want to correctly attribute statements which follow + BEGIN but do not touch any transactional tables. + */ + if (thd->m_transaction_psi == NULL) + { + thd->m_transaction_psi= MYSQL_START_TRANSACTION(&thd->m_transaction_state, + NULL, 0, thd->tx_isolation, + thd->tx_read_only, false); + DEBUG_SYNC(thd, "after_set_transaction_psi_before_set_transaction_gtid"); + //gtid_set_performance_schema_values(thd); + } + + DBUG_RETURN(MY_TEST(res)); +} + + +/** + Commit the current transaction, making its changes permanent. + + @param thd Current thread + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_commit(THD *thd) +{ + int res; + DBUG_ENTER("trans_commit"); + + if (trans_check(thd)) + DBUG_RETURN(TRUE); + + thd->server_status&= + ~(SERVER_STATUS_IN_TRANS | SERVER_STATUS_IN_TRANS_READONLY); + DBUG_PRINT("info", ("clearing SERVER_STATUS_IN_TRANS")); + res= ha_commit_trans(thd, TRUE); + + mysql_mutex_assert_not_owner(&LOCK_prepare_ordered); + mysql_mutex_assert_not_owner(mysql_bin_log.get_log_lock()); + mysql_mutex_assert_not_owner(&LOCK_after_binlog_sync); + mysql_mutex_assert_not_owner(&LOCK_commit_ordered); + + /* + if res is non-zero, then ha_commit_trans has rolled back the + transaction, so the hooks for rollback will be called. + */ +#ifdef HAVE_REPLICATION + if (res) + repl_semisync_master.wait_after_rollback(thd, FALSE); + else + repl_semisync_master.wait_after_commit(thd, FALSE); +#endif + thd->variables.option_bits&= ~(OPTION_BEGIN | OPTION_BINLOG_THIS_TRX); + thd->transaction->all.reset(); + thd->lex->start_transaction_opt= 0; + + /* The transaction should be marked as complete in P_S. */ + DBUG_ASSERT(thd->m_transaction_psi == NULL); + trans_track_end_trx(thd); + + DBUG_RETURN(MY_TEST(res)); +} + + +/** + Implicitly commit the current transaction. + + @note A implicit commit does not releases existing table locks. + + @param thd Current thread + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_commit_implicit(THD *thd) +{ + bool res= FALSE; + DBUG_ENTER("trans_commit_implicit"); + + if (trans_check(thd)) + DBUG_RETURN(TRUE); + + if (thd->variables.option_bits & OPTION_GTID_BEGIN) + { + DBUG_PRINT("error", ("OPTION_GTID_BEGIN is set. " + "Master and slave will have different GTID values")); + } + + if (thd->in_multi_stmt_transaction_mode() || + (thd->variables.option_bits & OPTION_TABLE_LOCK)) + { + /* Safety if one did "drop table" on locked tables */ + if (!thd->locked_tables_mode) + thd->variables.option_bits&= ~OPTION_TABLE_LOCK; + thd->server_status&= + ~(SERVER_STATUS_IN_TRANS | SERVER_STATUS_IN_TRANS_READONLY); + DBUG_PRINT("info", ("clearing SERVER_STATUS_IN_TRANS")); + res= MY_TEST(ha_commit_trans(thd, TRUE)); + } + + thd->variables.option_bits&= ~(OPTION_BEGIN | OPTION_BINLOG_THIS_TRX); + thd->transaction->all.reset(); + + /* The transaction should be marked as complete in P_S. */ + DBUG_ASSERT(thd->m_transaction_psi == NULL); + + /* + Upon implicit commit, reset the current transaction + isolation level and access mode. We do not care about + @@session.completion_type since it's documented + to not have any effect on implicit commit. + */ + trans_reset_one_shot_chistics(thd); + + trans_track_end_trx(thd); + + DBUG_RETURN(res); +} + + +/** + Rollback the current transaction, canceling its changes. + + @param thd Current thread + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_rollback(THD *thd) +{ + int res; + DBUG_ENTER("trans_rollback"); + + if (trans_check(thd)) + DBUG_RETURN(TRUE); + + thd->server_status&= + ~(SERVER_STATUS_IN_TRANS | SERVER_STATUS_IN_TRANS_READONLY); + DBUG_PRINT("info", ("clearing SERVER_STATUS_IN_TRANS")); + res= ha_rollback_trans(thd, TRUE); +#ifdef HAVE_REPLICATION + repl_semisync_master.wait_after_rollback(thd, FALSE); +#endif + /* Reset the binlog transaction marker */ + thd->variables.option_bits&= ~(OPTION_BEGIN | OPTION_BINLOG_THIS_TRX | + OPTION_GTID_BEGIN); + thd->transaction->all.reset(); + thd->lex->start_transaction_opt= 0; + + /* The transaction should be marked as complete in P_S. */ + DBUG_ASSERT(thd->m_transaction_psi == NULL); + + trans_track_end_trx(thd); + + DBUG_RETURN(MY_TEST(res)); +} + + +/** + Implicitly rollback the current transaction, typically + after deadlock was discovered. + + @param thd Current thread + + @retval False Success + @retval True Failure + + @note ha_rollback_low() which is indirectly called by this + function will mark XA transaction for rollback by + setting appropriate RM error status if there was + transaction rollback request. +*/ + +bool trans_rollback_implicit(THD *thd) +{ + int res; + DBUG_ENTER("trans_rollback_implict"); + + /* + Always commit/rollback statement transaction before manipulating + with the normal one. + Don't perform rollback in the middle of sub-statement, wait till + its end. + */ + DBUG_ASSERT(thd->transaction->stmt.is_empty() && !thd->in_sub_stmt); + + thd->server_status&= ~(SERVER_STATUS_IN_TRANS | SERVER_STATUS_IN_TRANS_READONLY); + DBUG_PRINT("info", ("clearing SERVER_STATUS_IN_TRANS")); + res= ha_rollback_trans(thd, true); + /* + We don't reset OPTION_BEGIN flag below to simulate implicit start + of new transacton in @@autocommit=1 mode. This is necessary to + preserve backward compatibility. + */ + thd->variables.option_bits&= ~(OPTION_BINLOG_THIS_TRX); + thd->transaction->all.reset(); + + /* Rollback should clear transaction_rollback_request flag. */ + DBUG_ASSERT(!thd->transaction_rollback_request); + /* The transaction should be marked as complete in P_S. */ + DBUG_ASSERT(thd->m_transaction_psi == NULL); + + trans_track_end_trx(thd); + + DBUG_RETURN(MY_TEST(res)); +} + + +/** + Commit the single statement transaction. + + @note Note that if the autocommit is on, then the following call + inside InnoDB will commit or rollback the whole transaction + (= the statement). The autocommit mechanism built into InnoDB + is based on counting locks, but if the user has used LOCK + TABLES then that mechanism does not know to do the commit. + + @param thd Current thread + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_commit_stmt(THD *thd) +{ + DBUG_ENTER("trans_commit_stmt"); + int res= FALSE; + /* + We currently don't invoke commit/rollback at end of + a sub-statement. In future, we perhaps should take + a savepoint for each nested statement, and release the + savepoint when statement has succeeded. + */ + DBUG_ASSERT(!(thd->in_sub_stmt)); + + thd->merge_unsafe_rollback_flags(); + + if (thd->transaction->stmt.ha_list) + { + res= ha_commit_trans(thd, FALSE); + if (! thd->in_active_multi_stmt_transaction()) + { + trans_reset_one_shot_chistics(thd); + } + } + + mysql_mutex_assert_not_owner(&LOCK_prepare_ordered); + mysql_mutex_assert_not_owner(mysql_bin_log.get_log_lock()); + mysql_mutex_assert_not_owner(&LOCK_after_binlog_sync); + mysql_mutex_assert_not_owner(&LOCK_commit_ordered); + + /* + if res is non-zero, then ha_commit_trans has rolled back the + transaction, so the hooks for rollback will be called. + */ + if (res) + { +#ifdef HAVE_REPLICATION + repl_semisync_master.wait_after_rollback(thd, FALSE); +#endif + } + else + { +#ifdef HAVE_REPLICATION + repl_semisync_master.wait_after_commit(thd, FALSE); +#endif + } + + /* In autocommit=1 mode the transaction should be marked as complete in P_S */ + DBUG_ASSERT(thd->in_active_multi_stmt_transaction() || + thd->m_transaction_psi == NULL); + + thd->transaction->stmt.reset(); + + DBUG_RETURN(MY_TEST(res)); +} + + +/** + Rollback the single statement transaction. + + @param thd Current thread + + @retval FALSE Success + @retval TRUE Failure +*/ +bool trans_rollback_stmt(THD *thd) +{ + DBUG_ENTER("trans_rollback_stmt"); + + /* + We currently don't invoke commit/rollback at end of + a sub-statement. In future, we perhaps should take + a savepoint for each nested statement, and release the + savepoint when statement has succeeded. + */ + DBUG_ASSERT(! thd->in_sub_stmt); + + thd->merge_unsafe_rollback_flags(); + + if (thd->transaction->stmt.ha_list) + { + ha_rollback_trans(thd, FALSE); + if (! thd->in_active_multi_stmt_transaction()) + trans_reset_one_shot_chistics(thd); + } + +#ifdef HAVE_REPLICATION + repl_semisync_master.wait_after_rollback(thd, FALSE); +#endif + + /* In autocommit=1 mode the transaction should be marked as complete in P_S */ + DBUG_ASSERT(thd->in_active_multi_stmt_transaction() || + thd->m_transaction_psi == NULL); + + thd->transaction->stmt.reset(); + + DBUG_RETURN(FALSE); +} + +/* Find a named savepoint in the current transaction. */ +static SAVEPOINT ** +find_savepoint(THD *thd, LEX_CSTRING name) +{ + SAVEPOINT **sv= &thd->transaction->savepoints; + + while (*sv) + { + if (system_charset_info->strnncoll( + (uchar *) name.str, name.length, + (uchar *) (*sv)->name, (*sv)->length) == 0) + break; + sv= &(*sv)->prev; + } + + return sv; +} + + +/** + Set a named transaction savepoint. + + @param thd Current thread + @param name Savepoint name + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_savepoint(THD *thd, LEX_CSTRING name) +{ + SAVEPOINT **sv, *newsv; + DBUG_ENTER("trans_savepoint"); + + if (!(thd->in_multi_stmt_transaction_mode() || thd->in_sub_stmt) || + !opt_using_transactions) + DBUG_RETURN(FALSE); + + if (thd->transaction->xid_state.check_has_uncommitted_xa()) + DBUG_RETURN(TRUE); + + sv= find_savepoint(thd, name); + + if (*sv) /* old savepoint of the same name exists */ + { + newsv= *sv; + ha_release_savepoint(thd, *sv); + *sv= (*sv)->prev; + } + else if ((newsv= (SAVEPOINT *) alloc_root(&thd->transaction->mem_root, + savepoint_alloc_size)) == NULL) + { + my_error(ER_OUT_OF_RESOURCES, MYF(0)); + DBUG_RETURN(TRUE); + } + + newsv->name= strmake_root(&thd->transaction->mem_root, name.str, name.length); + newsv->length= (uint)name.length; + + /* + if we'll get an error here, don't add new savepoint to the list. + we'll lose a little bit of memory in transaction mem_root, but it'll + be free'd when transaction ends anyway + */ + if (unlikely(ha_savepoint(thd, newsv))) + DBUG_RETURN(TRUE); + + newsv->prev= thd->transaction->savepoints; + thd->transaction->savepoints= newsv; + + /* + Remember locks acquired before the savepoint was set. + They are used as a marker to only release locks acquired after + the setting of this savepoint. + Note: this works just fine if we're under LOCK TABLES, + since mdl_savepoint() is guaranteed to be beyond + the last locked table. This allows to release some + locks acquired during LOCK TABLES. + */ + newsv->mdl_savepoint= thd->mdl_context.mdl_savepoint(); + + DBUG_RETURN(FALSE); +} + + +/** + Rollback a transaction to the named savepoint. + + @note Modifications that the current transaction made to + rows after the savepoint was set are undone in the + rollback. + + @note Savepoints that were set at a later time than the + named savepoint are deleted. + + @param thd Current thread + @param name Savepoint name + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_rollback_to_savepoint(THD *thd, LEX_CSTRING name) +{ + int res= FALSE; + SAVEPOINT *sv= *find_savepoint(thd, name); + DBUG_ENTER("trans_rollback_to_savepoint"); + + if (sv == NULL) + { + my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "SAVEPOINT", name.str); + DBUG_RETURN(TRUE); + } + + if (thd->transaction->xid_state.check_has_uncommitted_xa()) + DBUG_RETURN(TRUE); + + if (ha_rollback_to_savepoint(thd, sv)) + res= TRUE; + else if (((thd->variables.option_bits & OPTION_BINLOG_THIS_TRX) || + thd->transaction->all.modified_non_trans_table) && + !thd->slave_thread) + push_warning(thd, Sql_condition::WARN_LEVEL_WARN, + ER_WARNING_NOT_COMPLETE_ROLLBACK, + ER_THD(thd, ER_WARNING_NOT_COMPLETE_ROLLBACK)); + + thd->transaction->savepoints= sv; + + if (res) + /* An error occurred during rollback; we cannot release any MDL */; + else if (thd->variables.sql_log_bin && + (WSREP_EMULATE_BINLOG_NNULL(thd) || mysql_bin_log.is_open())) + /* In some cases (such as with non-transactional tables) we may + choose to preserve events that were added after the SAVEPOINT, + delimiting them by SAVEPOINT and ROLLBACK TO SAVEPOINT statements. + Prematurely releasing MDL on such objects would break replication. */; + else if (ha_rollback_to_savepoint_can_release_mdl(thd)) + thd->mdl_context.rollback_to_savepoint(sv->mdl_savepoint); + + DBUG_RETURN(MY_TEST(res)); +} + + +/** + Remove the named savepoint from the set of savepoints of + the current transaction. + + @note No commit or rollback occurs. It is an error if the + savepoint does not exist. + + @param thd Current thread + @param name Savepoint name + + @retval FALSE Success + @retval TRUE Failure +*/ + +bool trans_release_savepoint(THD *thd, LEX_CSTRING name) +{ + int res= FALSE; + SAVEPOINT *sv= *find_savepoint(thd, name); + DBUG_ENTER("trans_release_savepoint"); + + if (sv == NULL) + { + my_error(ER_SP_DOES_NOT_EXIST, MYF(0), "SAVEPOINT", name.str); + DBUG_RETURN(TRUE); + } + + if (ha_release_savepoint(thd, sv)) + res= TRUE; + + thd->transaction->savepoints= sv->prev; + + DBUG_RETURN(MY_TEST(res)); +} |