diff options
Diffstat (limited to 'sql/ha_innodb.cc')
| -rw-r--r-- | sql/ha_innodb.cc | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/sql/ha_innodb.cc b/sql/ha_innodb.cc index 0ccac274d58..072f6866d7a 100644 --- a/sql/ha_innodb.cc +++ b/sql/ha_innodb.cc @@ -1483,7 +1483,7 @@ innobase_commit( /* We were instructed to commit the whole transaction, or this is an SQL statement end and autocommit is on */ - /* We need current binlog position for HotBackup to work. + /* We need current binlog position for ibbackup to work. Note, the position is current because of prepare_commit_mutex */ trx->mysql_log_file_name = mysql_bin_log.get_log_fname(); trx->mysql_log_offset = @@ -6472,6 +6472,25 @@ innobase_xa_prepare( if (thd->lex->sql_command != SQLCOM_XA_PREPARE) { + /* For ibbackup to work the order of transactions in binlog + and InnoDB must be the same. Consider the situation + + thread1> prepare; write to binlog; ... + <context switch> + thread2> prepare; write to binlog; commit + thread1> ... commit + + To ensure this will not happen we're taking the mutex on + prepare, and releasing it on commit. + + Note: only do it for normal commits, done via ha_commit_trans. + If 2pc protocol is executed by external transaction + coordinator, it will be just a regular MySQL client + executing XA PREPARE and XA COMMIT commands. + In this case we cannot know how many minutes or hours + will be between XA PREPARE and XA COMMIT, and we don't want + to block for undefined period of time. + */ pthread_mutex_lock(&prepare_commit_mutex); trx->active_trans = 2; } |