Commit 55ce4471 authored by unknown's avatar unknown
Browse files

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

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.


sql/log_event.cc:
  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.
sql/slave.cc:
  Removing code to step the group log position and just stepping
  the event log position when executing a Format_description_log_event.
  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.
parent cc4435ad

sql/log_event.cc

+13 −13
Original line number Diff line number Diff line
@@ -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.

      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.

     */

    if (thd->options & OPTION_BEGIN)

    rli->inc_event_relay_log_pos();

    else

    {

      rli->inc_group_relay_log_pos(0);

      flush_relay_log_info(rli);

    }

    DBUG_RETURN(0);

  }

sql/slave.cc

+16 −11
Original line number Diff line number Diff line
@@ -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)

      /*

        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();

      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);

      }



      /*

        Protect against common user error of setting the counter to 1