| Bug #30294 | blackhole engine causes 100% with 2 alter table statements running | ||
|---|---|---|---|
| Submitted: | 8 Aug 2007 7:06 | Modified: | 24 Jan 2008 19:59 |
| Reporter: | Shane Bester (Platinum Quality Contributor) | Email Updates: | |
| Status: | Closed | Impact on me: | |
| Category: | MySQL Server: Locking | Severity: | S2 (Serious) |
| Version: | 5.0.48BK | OS: | Any |
| Assigned to: | Sergei Glukhov | CPU Architecture: | Any |
| Tags: | alter, blackhole, hang | ||
[8 Aug 2007 7:10]
MySQL Verification Team
testcase
Attachment: bug30294.c (text/plain), 5.12 KiB.
[8 Aug 2007 7:12]
MySQL Verification Team
luckily 5.1.21 didn't appear to have this problem
[9 Nov 2007 7:07]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/37407 ChangeSet@1.2554, 2007-11-09 11:02:05+04:00, gluh@mysql.com +3 -0 Bug#30294 blackhole engine causes 100% with 2 alter table statements running Implement neccessary shared lock structure for table locks. This is the backport of bug26241 fix.
[16 Nov 2007 10:52]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/37937 ChangeSet@1.2576, 2007-11-16 14:46:36+04:00, gluh@mysql.com +3 -0 Bug#30294 blackhole engine causes 100% with 2 alter table statements running Implement neccessary shared lock structure for table locks. This is the backport of bug26241 fix.
[14 Dec 2007 8:15]
Bugs System
Pushed into 5.0.54
[14 Dec 2007 8:18]
Bugs System
Pushed into 5.1.23-rc
[14 Dec 2007 8:22]
Bugs System
Pushed into 6.0.5-alpha
[24 Jan 2008 19:59]
Paul DuBois
Noted in 5.0.54, 5.1.23, 6.0.5 changelogs. Simultaneous ALTER TABLE statements for BLACKHOLE tables caused 100% CPU use due to locking problems.
Description: 100% cpu hang on this bug. the queries aren't killable either. mysql> show processlist; ------+---------------------+------------------------------------+ Time | State | Info | ------+---------------------+------------------------------------+ 1 | | NULL | 271 | rename result table | alter table `t1` add key `a`(`id`) | 271 | rename result table | alter table `t1` add key `a`(`id`) | 0 | NULL | show processlist | ------+---------------------+------------------------------------+ 4 rows in set (0.00 sec) t1 is a simple table defined as: create table `t1`(`id` int)engine=blackhole How to repeat: see attachment. Suggested fix: If we are to support multiple storage engines and they will truly be pluggable, the locking interfaces should work better than this.