Bug #61453 Segmentation Fault
Submitted: 8 Jun 2011 21:35 Modified: 18 Jun 2011 11:02
Reporter: Chris Wagner Email Updates:
Status: Duplicate Impact on me:
Category:MySQL Server: General Severity:S2 (Serious)
Version:5.5.13 OS:Linux (Ubuntu)
Assigned to: CPU Architecture:Any
Tags: myisam_use_mmap, mysqld got signal 11, segfault, segv, Signal 11, SIGSEGV

[8 Jun 2011 21:35] Chris Wagner
MySQL has begun crashing on us.  Basically our application is Perl driven and gathers stats on a large database of data.  Matching data is collected from source MyISAM tables into a temp table.  Stats are generated from that and saved to InnoDB reporting tables.  There is no one thing that causes the crash.  Scripts will be at random points in the process and the server just dies with "mysqld got signal 11".  The crash frequency is daily when a job is running.  I will attach the error log output.

Our box is a Dell 8-way Xeon (hyperthreading) with 64 GB of RAM and hardware RAID going to 15k drives.

OS info:
Linux version 2.6.35-25-server (buildd@allspice) (gcc version 4.4.3 (Ubuntu 4.4.
3-4ubuntu5) ) #44~lucid1-Ubuntu SMP Tue Jan 25 19:34:09 UTC 2011
Ubuntu 2.6.35-25.44~lucid1-server


How to repeat:
Run queries.
[8 Jun 2011 21:36] Chris Wagner
Error log excerpts

Attachment: crashes.txt (text/plain), 7.03 KiB.

[8 Jun 2011 21:41] Chris Wagner

Attachment: config1.txt (text/plain), 1.18 KiB.

[8 Jun 2011 21:41] MySQL Verification Team
Thank you for the bug report. Could you please elaborate what query provoked the crash (a dump of the table(s) and query could help to repeat it on our side), your my.cnf and the back trace. Thanks in advance.
[8 Jun 2011 21:45] MySQL Verification Team
Please disregard some question I did before I was editing simultaneously with you. However the dump of table(s) would be nice. Thanks.
[8 Jun 2011 22:15] Chris Wagner
Thanks for responding.  Each crash occured while accessing a different table so I'm not sure what I would show u.  Once it was on SELECT INTO OUTFILE from MyISAM.  Another time inside an InnoDB transaction.  The MyISAM tables are 8x8 partitioned due to size.  The InnoDB tables are pretty vanilla standalone tables.
[8 Jun 2011 23:54] Chris Wagner
Just experienced a new crash.  This time however it printed a message to the console about an invalid pointer.  *see attachment*
[8 Jun 2011 23:56] Chris Wagner
console messages and error log for crash

Attachment: crashes2.txt (text/plain), 20.10 KiB.

[9 Jun 2011 5:24] Valeriy Kravchuk
Please, try to comment out:


in my.cnf, restart and check if you'll ever get any similar crashes.
[10 Jun 2011 18:38] Chris Wagner
Did that.  Now waiting to see how it acts.
[15 Jun 2011 18:01] MySQL Verification Team
Please re-open when you are done with the result of myisam_use_mmap. Thanks.
[17 Jun 2011 17:36] Chris Wagner
It's been several days and I've run several large jobs and there hasn't been any new crashes.  It would seem that myisam_use_mmap is indeed the source of the crashing.  I don't recall anything in the manual about that being a stability risk.
[17 Jun 2011 18:24] MySQL Verification Team
see bug #48726 ...
[18 Jun 2011 11:02] Valeriy Kravchuk
Duplicate of bug #48726.