diff options
Diffstat (limited to 'storage/innobase/trx/trx0roll.cc')
| -rw-r--r-- | storage/innobase/trx/trx0roll.cc | 47 |
1 files changed, 22 insertions, 25 deletions
diff --git a/storage/innobase/trx/trx0roll.cc b/storage/innobase/trx/trx0roll.cc index a52724444ec..c5a7c2ca625 100644 --- a/storage/innobase/trx/trx0roll.cc +++ b/storage/innobase/trx/trx0roll.cc @@ -1,7 +1,7 @@ /***************************************************************************** Copyright (c) 1996, 2017, Oracle and/or its affiliates. All Rights Reserved. -Copyright (c) 2016, 2019, MariaDB Corporation. +Copyright (c) 2016, 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 @@ -238,10 +238,21 @@ dberr_t trx_rollback_for_mysql(trx_t* trx) case TRX_STATE_PREPARED_RECOVERED: ut_ad(!trx_is_autocommit_non_locking(trx)); if (trx->rsegs.m_redo.undo || trx->rsegs.m_redo.old_insert) { - /* Change the undo log state back from - TRX_UNDO_PREPARED to TRX_UNDO_ACTIVE - so that if the system gets killed, - recovery will perform the rollback. */ + /* The XA ROLLBACK of a XA PREPARE transaction + will consist of multiple mini-transactions. + + As the very first step of XA ROLLBACK, we must + change the undo log state back from + TRX_UNDO_PREPARED to TRX_UNDO_ACTIVE, in order + to ensure that recovery will complete the + rollback. + + Failure to perform this step could cause a + situation where we would roll back part of + a XA PREPARE transaction, the server would be + killed, and finally, the transaction would be + recovered in XA PREPARE state, with some of + the actions already having been rolled back. */ ut_ad(!trx->rsegs.m_redo.undo || trx->rsegs.m_redo.undo->rseg == trx->rsegs.m_redo.rseg); @@ -260,29 +271,15 @@ dberr_t trx_rollback_for_mysql(trx_t* trx) &mtr); } mutex_exit(&trx->rsegs.m_redo.rseg->mutex); - /* Persist the XA ROLLBACK, so that crash - recovery will replay the rollback in case - the redo log gets applied past this point. */ + /* Write the redo log for the XA ROLLBACK + state change to the global buffer. It is + not necessary to flush the redo log. If + a durable log write of a later mini-transaction + takes place for whatever reason, then this state + change will be durable as well. */ mtr.commit(); ut_ad(mtr.commit_lsn() > 0); } -#ifdef ENABLED_DEBUG_SYNC - if (trx->mysql_thd == NULL) { - /* We could be executing XA ROLLBACK after - XA PREPARE and a server restart. */ - } else if (!trx->has_logged_persistent()) { - /* innobase_close_connection() may roll back a - transaction that did not generate any - persistent undo log. The DEBUG_SYNC - would cause an assertion failure for a - disconnected thread. - - NOTE: InnoDB will not know about the XID - if no persistent undo log was generated. */ - } else { - DEBUG_SYNC_C("trx_xa_rollback"); - } -#endif /* ENABLED_DEBUG_SYNC */ return(trx_rollback_for_mysql_low(trx)); case TRX_STATE_COMMITTED_IN_MEMORY: |