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|
/* 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;
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));
}
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