diff options
| author | Kristian Nielsen <knielsen@knielsen-hq.org> | 2016-11-16 11:00:38 +0100 |
|---|---|---|
| committer | Rasmus Johansson <rasmus@mariadb.com> | 2016-11-17 12:32:13 +0200 |
| commit | 7618e953e960a374f555b93be99cbad9af7ba503 (patch) | |
| tree | 4809a67bda0584859199123d7b70f0ba3843a7ed | |
| parent | 7dd9be0fa1536c6c2fb580a570f5c44b58a4d0a4 (diff) | |
| download | mariadb-git-bb-10.0-MDEV-10863.tar.gz | |
Fix incorrect reading of events from relaylog in parallel replication.bb-10.0-MDEV-10863
The SQL thread keeps track of the position in the current relay log from
which to read the next event. This position is not normally used, but a
certain interaction with the IO thread can cause the SQL thread to re-open
the relay log and seek to the stored position.
In parallel replication, there were a couple of places where the position
was not updated. This created a race where a re-open of the relay log could
seek to the wrong position and start re-reading and processing events
already handled once, causing various kinds of problems.
Fix this by moving the position update into a single place in
apply_event_and_update_pos(), which should ensure that the position is
always updated in the parallel replication case.
This problem was found from the testcase of MDEV-10863, but it is logically
a separate problem.
| -rw-r--r-- | sql/rpl_parallel.cc | 1 | ||||
| -rw-r--r-- | sql/slave.cc | 7 |
2 files changed, 7 insertions, 1 deletions
diff --git a/sql/rpl_parallel.cc b/sql/rpl_parallel.cc index 98712f18c1b..23f61a82a90 100644 --- a/sql/rpl_parallel.cc +++ b/sql/rpl_parallel.cc @@ -2614,7 +2614,6 @@ rpl_parallel::do_event(rpl_group_info *serial_rgi, Log_event *ev, /* Queue the event for processing. */ - rli->event_relay_log_pos= rli->future_event_relay_log_pos; qev->ir= rli->last_inuse_relaylog; ++qev->ir->queued_count; cur_thread->enqueue(qev); diff --git a/sql/slave.cc b/sql/slave.cc index e6a0ac086a8..65bcdc48c6a 100644 --- a/sql/slave.cc +++ b/sql/slave.cc @@ -3569,6 +3569,13 @@ static int exec_relay_log_event(THD* thd, Relay_log_info* rli, if (rli->mi->using_parallel()) { int res= rli->parallel.do_event(serial_rgi, ev, event_size); + /* + In parallel replication, we need to update the relay log position + immediately so that it will be the correct position from which to + read the next event. + */ + if (res == 0) + rli->event_relay_log_pos= rli->future_event_relay_log_pos; if (res >= 0) DBUG_RETURN(res); /* |