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MDEV-7065: Incorrect relay log position in parallel replication after retry of transaction

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The retry of an event group in parallel replication set the wrong value for
the end log position of the event that was retried
(qev->future_event_relay_log_pos). It was too large by the size of the event,
so it pointed into the middle of the following event.

If the retry happened in the very last event of the event group, _and_ the SQL
thread was stopped just after successfully retrying that event, then the SQL
threads's relay log position would be left incorrect. Restarting the SQL
thread could then try to read events from a garbage offset in the relay log,
usually leading to an error about not being able to read the event.
This commit is contained in:
Kristian Nielsen
2014-11-13 10:46:09 +01:00
parent d08b893b39
commit 3dcd01e5e6
3 changed files with 111 additions and 2 deletions
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14
sql/rpl_parallel.cc
View File

@ -446,7 +446,7 @@ do_retry:
ev->thd= thd;
mysql_mutex_lock(&rpt->LOCK_rpl_thread);
qev= rpt->retry_get_qev(ev, orig_qev, log_name, cur_offset,
qev= rpt->retry_get_qev(ev, orig_qev, log_name, old_offset,
cur_offset - old_offset);
mysql_mutex_unlock(&rpt->LOCK_rpl_thread);
if (!qev)
@ -776,6 +776,18 @@ handle_rpl_parallel_thread(void *arg)
if (likely(!rgi->worker_error) && !skip_event_group)
{
++rgi->retry_event_count;
#ifndef DBUG_OFF
err= 0;
DBUG_EXECUTE_IF("rpl_parallel_simulate_temp_err_xid",
if (event_type == XID_EVENT)
{
thd->clear_error();
thd->get_stmt_da()->reset_diagnostics_area();
my_error(ER_LOCK_DEADLOCK, MYF(0));
err= 1;
});
if (!err)
#endif
err= rpt_handle_event(qev, rpt);
delete_or_keep_event_post_apply(rgi, event_type, qev->ev);
DBUG_EXECUTE_IF("rpl_parallel_simulate_temp_err_gtid_0_x_100",