From 2783fc7d14bc8ad16acfeb509d3b19615023f47a Mon Sep 17 00:00:00 2001
From: Alexey Botchkov <holyfoot@askmonty.org>
Date: Wed, 23 Mar 2016 12:16:39 +0400
Subject: MDEV-717 LP:1003679 - Wrong binlog order on concurrent DROP schema
and CREATE function.
The cause of the issue is when DROP DATABASE takes
metadata lock and is in progress through it's
execution, a concurrently running CREATE FUNCTION checks
for the existence of database which it succeeds and then it
waits on the metadata lock. Once DROP DATABASE writes to
BINLOG and finally releases the metadata lock on schema
object, the CREATE FUNCTION waiting on metadata lock
gets in it's code path and succeeds and writes to binlog.
---
sql/events.cc | 29 +++++++++++++++++++++--------
1 file changed, 21 insertions(+), 8 deletions(-)
(limited to 'sql/events.cc')
diff --git a/sql/events.cc b/sql/events.cc
index b80ec993ac4..77dbb8b82e5 100644
--- a/sql/events.cc
+++ b/sql/events.cc
@@ -333,6 +333,10 @@ Events::create_event(THD *thd, Event_parse_data *parse_data)
if (check_access(thd, EVENT_ACL, parse_data->dbname.str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
+ if (lock_object_name(thd, MDL_key::EVENT,
+ parse_data->dbname.str, parse_data->name.str))
+ DBUG_RETURN(TRUE);
+
if (check_db_dir_existence(parse_data->dbname.str))
{
my_error(ER_BAD_DB_ERROR, MYF(0), parse_data->dbname.str);
@@ -347,10 +351,6 @@ Events::create_event(THD *thd, Event_parse_data *parse_data)
*/
save_binlog_format= thd->set_current_stmt_binlog_format_stmt();
- if (lock_object_name(thd, MDL_key::EVENT,
- parse_data->dbname.str, parse_data->name.str))
- DBUG_RETURN(TRUE);
-
if (thd->lex->create_info.or_replace() && event_queue)
event_queue->drop_event(thd, parse_data->dbname, parse_data->name);
@@ -454,6 +454,16 @@ Events::update_event(THD *thd, Event_parse_data *parse_data,
if (check_access(thd, EVENT_ACL, parse_data->dbname.str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
+ if (lock_object_name(thd, MDL_key::EVENT,
+ parse_data->dbname.str, parse_data->name.str))
+ DBUG_RETURN(TRUE);
+
+ if (check_db_dir_existence(parse_data->dbname.str))
+ {
+ my_error(ER_BAD_DB_ERROR, MYF(0), parse_data->dbname.str);
+ DBUG_RETURN(TRUE);
+ }
+
if (new_dbname) /* It's a rename */
{
@@ -476,6 +486,13 @@ Events::update_event(THD *thd, Event_parse_data *parse_data,
if (check_access(thd, EVENT_ACL, new_dbname->str, NULL, NULL, 0, 0))
DBUG_RETURN(TRUE);
+ /*
+ Acquire mdl exclusive lock on target database name.
+ */
+ if (lock_object_name(thd, MDL_key::EVENT,
+ new_dbname->str, new_name->str))
+ DBUG_RETURN(TRUE);
+
/* Check that the target database exists */
if (check_db_dir_existence(new_dbname->str))
{
@@ -490,10 +507,6 @@ Events::update_event(THD *thd, Event_parse_data *parse_data,
*/
save_binlog_format= thd->set_current_stmt_binlog_format_stmt();
- if (lock_object_name(thd, MDL_key::EVENT,
- parse_data->dbname.str, parse_data->name.str))
- DBUG_RETURN(TRUE);
-
/* On error conditions my_error() is called so no need to handle here */
if (!(ret= db_repository->update_event(thd, parse_data,
new_dbname, new_name)))
--
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