Re: [Maria-developers] Rev 4056: MDEV-5616 - Deadlock between CREATE/DROP FUNCTION and SELECT from view
Hi, Sergey! Ok to push. A couple of comments below. On Feb 07, Sergey Vojtovich wrote:
revno: 4056 revision-id: svoj@mariadb.org-20140207100451-8pnzn85pjjwvwfs4 parent: elenst@wheezy-64.home-20140205102537-7ern5gfca6a6ojg3 committer: Sergey Vojtovich <svoj@mariadb.org> branch nick: 5.5-mdev5616 timestamp: Fri 2014-02-07 14:04:51 +0400 message: MDEV-5616 - Deadlock between CREATE/DROP FUNCTION and SELECT from view
Deadlock happened due to mixed lock order. CREATE/DROP function: wrlock(THR_LOCK_udf) -> lock(LOCK_open) SELECT from view: lock(LOCK_open) -> rdlock(THR_LOCK_udf)
Fixed CREATE/DROP function so that LOCK_open does not intersect with wrlock(THR_LOCK_udf).
10.0 is not affected: it doesn't hold LOCK_open while opening view.
I'm pretty sure it'll auto-merge and nobody will remember this warning at that time. So this patch will be in 10.0. Perhaps you should add #if MYSQL_VERSION_ID > 50600 #error don't merge into 10.0 #endif ? Or, may be, it's not a big deal to have it in 10.0...
=== modified file 'sql/sql_udf.cc' --- a/sql/sql_udf.cc 2012-03-27 23:04:46 +0000 +++ b/sql/sql_udf.cc 2014-02-07 10:04:51 +0000 @@ -466,7 +467,11 @@ int mysql_create_function(THD *thd,udf_f if ((save_binlog_row_based= thd->is_current_stmt_binlog_format_row())) thd->clear_current_stmt_binlog_format_row();
+ tables.init_one_table("mysql", 5, "func", 4, "func", TL_WRITE);
I know it's a old line that you've moved and it's a matter of taste anyway, so up to you, but generally I prefer to see STRING_WITH_LEN here. It 1) makes a certain class of typos impossible; 2) documents the code, one doesn't need to think what these 4 and 5 stand for. Regards, Sergei
Hi Sergei, thanks for your comments. On Thu, Feb 13, 2014 at 12:36:51PM +0100, Sergei Golubchik wrote:
Hi, Sergey!
Ok to push. A couple of comments below.
On Feb 07, Sergey Vojtovich wrote:
revno: 4056 revision-id: svoj@mariadb.org-20140207100451-8pnzn85pjjwvwfs4 parent: elenst@wheezy-64.home-20140205102537-7ern5gfca6a6ojg3 committer: Sergey Vojtovich <svoj@mariadb.org> branch nick: 5.5-mdev5616 timestamp: Fri 2014-02-07 14:04:51 +0400 message: MDEV-5616 - Deadlock between CREATE/DROP FUNCTION and SELECT from view
Deadlock happened due to mixed lock order. CREATE/DROP function: wrlock(THR_LOCK_udf) -> lock(LOCK_open) SELECT from view: lock(LOCK_open) -> rdlock(THR_LOCK_udf)
Fixed CREATE/DROP function so that LOCK_open does not intersect with wrlock(THR_LOCK_udf).
10.0 is not affected: it doesn't hold LOCK_open while opening view.
I'm pretty sure it'll auto-merge and nobody will remember this warning at that time. So this patch will be in 10.0.
Perhaps you should add
#if MYSQL_VERSION_ID > 50600 #error don't merge into 10.0 #endif
? Or, may be, it's not a big deal to have it in 10.0... I believe it is a good idea to have it in 10.0: the less lock relationships we have - the better.
=== modified file 'sql/sql_udf.cc' --- a/sql/sql_udf.cc 2012-03-27 23:04:46 +0000 +++ b/sql/sql_udf.cc 2014-02-07 10:04:51 +0000 @@ -466,7 +467,11 @@ int mysql_create_function(THD *thd,udf_f if ((save_binlog_row_based= thd->is_current_stmt_binlog_format_row())) thd->clear_current_stmt_binlog_format_row();
+ tables.init_one_table("mysql", 5, "func", 4, "func", TL_WRITE);
I know it's a old line that you've moved and it's a matter of taste anyway, so up to you, but generally I prefer to see STRING_WITH_LEN here. It 1) makes a certain class of typos impossible; 2) documents the code, one doesn't need to think what these 4 and 5 stand for.
Will do. Thanks, Sergey
participants (2)
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Sergei Golubchik -
Sergey Vojtovich