Bug #63621 MySQL

• Submitted: 6 Dec 2011 9:04
• Modified: 6 Dec 2011 12:39
• Reporter: Dominik P
• Status: Can't repeat
• Category: MySQL Server: MyISAM storage engine
• Severity: S1 (Critical)
• Version: 5.1.43-community-log
• OS: Windows
• CPU Architecture: Any
• Tags: .MYD or .MYI moved to a filename postfixed with .deleted

[6 Dec 2011 9:04] Dominik P

Description:
Sometimes .MYD or .MYI files become renamed to .MYD.??????.deleted as illustrated in this attachment: http://bugs.mysql.com/file.php?id=15324

However, mmap is disabled for myisam:

show variables like 'myisam_%';
myisam_data_pointer_size	6
myisam_max_sort_file_size	107374182400
myisam_mmap_size	4294967295
myisam_recover_options	OFF
myisam_repair_threads	1
myisam_sort_buffer_size	36700160
myisam_stats_method	nulls_unequal
myisam_use_mmap	OFF

Automatic and manual repairs fail since the .MYD file is no longer present, but we were always able to recover all the data by renaming the affected files back to their original name and run "repair table" on the affected table.

How to repeat:
We used to run into this problem but were unable to reproduce it. However, http://bugs.mysql.com/bug.php?id=49030 might be related.

[6 Dec 2011 12:04] MySQL Verification Team

Thank you for the bug report. Re-open this bug report if you have a repeatable test case anyway test the latest release 5.1.60 (5.1.43 is quite older) and check for backup and antivirus programs acting on the tables files. Thanks.

[6 Dec 2011 12:39] Dominik P

Thanks for your feedback. We cannot upgrade all of our deployed applications. But we know that until now this problem happened on two different unrelated productive machines.

We probably do something that one of the installed MySQL versions does not like and we are willing to adapt ourselves to necessary workarounds. I just checked the version of the second host where this problem happened and it shows "5.1.34-community".

Could regular "check table" or "repair table" cause problems?