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MDEV-9573 'Stop slave' hangs on replication slave

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The reason for this is that stop slave takes LOCK_active_mi over the
whole operation while some slave operations will also need LOCK_active_mi
which causes deadlocks.

Fixed by introducing object counting for Master_info and not taking
LOCK_active_mi over stop slave or even stop_all_slaves()

Another benefit of this approach is that it allows:
- Multiple threads can run SHOW SLAVE STATUS at the same time
- START/STOP/RESET/SLAVE STATUS on a slave will not block other slaves
- Simpler interface for handling get_master_info()
- Added some missing unlock of 'log_lock' in error condtions
- Moved rpl_parallel_inactivate_pool(&global_rpl_thread_pool) to end
  of stop_slave() to not have to use LOCK_active_mi inside
  terminate_slave_threads()
- Changed argument for remove_master_info() to Master_info, as we always
  have this available
- Fixed core dump when doing FLUSH TABLES WITH READ LOCK and parallel
  replication. Problem was that waiting for pause_for_ftwrl was not done
  when deleting rpt->current_owner after a force_abort.
This commit is contained in:
Monty
2017-01-29 22:10:56 +02:00
committed by Sergei Golubchik
parent d5c54f3990
commit e65f667bb6
13 changed files with 539 additions and 345 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
sql/sql_repl.cc
View File

@ -3265,8 +3265,8 @@ bool change_master(THD* thd, Master_info* mi, bool *master_info_added)
LEX_MASTER_INFO* lex_mi= &thd->lex->mi;
DBUG_ENTER("change_master");
mysql_mutex_assert_owner(&LOCK_active_mi);
DBUG_ASSERT(master_info_index);
mysql_mutex_assert_owner(&LOCK_active_mi);
*master_info_added= false;
/*
@ -3646,7 +3646,6 @@ bool mysql_show_binlog_events(THD* thd)
int old_max_allowed_packet= thd->variables.max_allowed_packet;
Master_info *mi= 0;
LOG_INFO linfo;
DBUG_ENTER("mysql_show_binlog_events");
Log_event::init_show_field_list(&field_list);
@ -3674,13 +3673,9 @@ bool mysql_show_binlog_events(THD* thd)
}
else /* showing relay log contents */
{
mysql_mutex_lock(&LOCK_active_mi);
if (!master_info_index ||
!(mi= master_info_index->
get_master_info(&thd->variables.default_master_connection,
Sql_condition::WARN_LEVEL_ERROR)))
if (!(mi= get_master_info(&thd->variables.default_master_connection,
Sql_condition::WARN_LEVEL_ERROR)))
{
mysql_mutex_unlock(&LOCK_active_mi);
DBUG_RETURN(TRUE);
}
binary_log= &(mi->rli.relay_log);
@ -3700,7 +3695,7 @@ bool mysql_show_binlog_events(THD* thd)
if (mi)
{
/* We can unlock the mutex as we have a lock on the file */
mysql_mutex_unlock(&LOCK_active_mi);
mi->release();
mi= 0;
}
@ -3722,6 +3717,7 @@ bool mysql_show_binlog_events(THD* thd)
goto err;
}
/* These locks is here to enable syncronization with log_in_use() */
mysql_mutex_lock(&LOCK_thread_count);
thd->current_linfo = &linfo;
mysql_mutex_unlock(&LOCK_thread_count);
@ -3799,7 +3795,7 @@ bool mysql_show_binlog_events(THD* thd)
mysql_mutex_unlock(log_lock);
}
else if (mi)
mysql_mutex_unlock(&LOCK_active_mi);
mi->release();
// Check that linfo is still on the function scope.
DEBUG_SYNC(thd, "after_show_binlog_events");
@ -3820,8 +3816,9 @@ err:
else
my_eof(thd);
/* These locks is here to enable syncronization with log_in_use() */
mysql_mutex_lock(&LOCK_thread_count);
thd->current_linfo = 0;
thd->current_linfo= 0;
mysql_mutex_unlock(&LOCK_thread_count);
thd->variables.max_allowed_packet= old_max_allowed_packet;
DBUG_RETURN(ret);