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BUG#21474 (There is a rotation before the last table map):

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Removing code to step the group log position and just stepping
the event log position.  If the group log position were stepped
one time too many, it might be that the group starts at a position
that is not possible, e.g., at a Rows_log_event, or between an
Intvar_log_event and the following associated Query_log_event.
This commit is contained in:
mats@romeo.(none) 2006-10-10 15:18:21 +02:00
parent cb1fdf5165
commit 6c3b1f6eb0
2 changed files with 29 additions and 24 deletions
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26
sql/log_event.cc
View File

@ -2381,19 +2381,19 @@ int Format_description_log_event::exec_event(struct st_relay_log_info* rli)
if (server_id == (uint32) ::server_id)
{
/*
Do not modify rli->group_master_log_pos, as this event did not exist on
the master. That is, just update the *relay log* coordinates; this is
done by passing log_pos=0 to inc_group_relay_log_pos, like we do in
Stop_log_event::exec_event().
If in a transaction, don't touch group_* coordinates.
*/
if (thd->options & OPTION_BEGIN)
rli->inc_event_relay_log_pos();
else
{
rli->inc_group_relay_log_pos(0);
flush_relay_log_info(rli);
}
We only increase the relay log position if we are skipping
events and do not touch any group_* variables, nor flush the
relay log info. If there is a crash, we will have to re-skip
the events again, but that is a minor issue.
If we do not skip stepping the group log position (and the
server id was changed when restarting the server), it might well
be that we start executing at a position that is invalid, e.g.,
at a Rows_log_event or a Query_log_event preceeded by a
Intvar_log_event instead of starting at a Table_map_log_event or
the Intvar_log_event respectively.
*/
rli->inc_event_relay_log_pos();
DBUG_RETURN(0);
}

27
sql/slave.cc
View File

@ -3101,17 +3101,22 @@ static int exec_relay_log_event(THD* thd, RELAY_LOG_INFO* rli)
type_code != START_EVENT_V3 && type_code!= FORMAT_DESCRIPTION_EVENT))
{
DBUG_PRINT("info", ("event skipped"));
if (thd->options & OPTION_BEGIN)
rli->inc_event_relay_log_pos();
else
{
rli->inc_group_relay_log_pos((type_code == ROTATE_EVENT ||
type_code == STOP_EVENT ||
type_code == FORMAT_DESCRIPTION_EVENT) ?
LL(0) : ev->log_pos,
1/* skip lock*/);
flush_relay_log_info(rli);
}
/*
We only skip the event here and do not increase the group log
position. In the event that we have to restart, this means
that we might have to skip the event again, but that is a
minor issue.
If we were to increase the group log position when skipping an
event, it might be that we are restarting at the wrong
position and have events before that we should have executed,
so not increasing the group log position is a sure bet in this
case.
In this way, we just step the group log position when we
*know* that we are at the end of a group.
*/
rli->inc_event_relay_log_pos();
/*
Protect against common user error of setting the counter to 1