Ever ran into a situation where you saw “some important variable you really needed to know about=<optimized out>” while debugging?
How to obtain the “LES” (Last Executed Statement) from an Optimized Core Dump?
September 9, 2012 By 9 Comments
Fishing with dynamite, brought to you by the randgen and dbqp
November 16, 2011 By Leave a Comment
I tend to speak highly of the random query generator as a testing tool and thought I would share a story that shows how it can really shine. At our recent dev team meeting, we spent approximately 30 minutes of hack time to produce test cases for 3 rather hard to duplicate bugs. Of course, [...]
Percona XtraBackup 1.6
April 12, 2011 By 15 Comments
Percona XtraBackup 1.6 is now available for download and is the current stable release version of XtraBackup.
Data Corruption, DRBD and story of bug
November 29, 2010 By 6 Comments
Working with customer, I faced pretty nasty bug, which is actually not rare situation , but in this particular there are some lessons I would like to share. The case is pretty much described in bug 55981, or in pastebin. Everything below is related to InnoDB-plugin/XtraDB, but not to regular InnoDB ( i.e in MySQL [...]
Crashes while using MyISAM with multiple key caches
July 18, 2009 By Leave a Comment
Over last couple of years I have ran into random MySQL crashes in production when multiple key caches were used. Unfortunately this never was frequent or critical enough issue so I could spend time creating repeatable test case and search of the bug in the MySQL database did not find anything. Recently we had this [...]
Recovery beyond data restore
August 2, 2008 By 11 Comments
Quite frequently I see customers looking at recovery as on ability to restore data from backup which can be far from being enough to restore the whole system to operating state, especially for complex systems. Instead of looking just at data restore process you better look at the whole process which is required to bring [...]
Innodb Recovery Update – The tricks what failed.
May 24, 2007 By 3 Comments
As I wrote we had been recovering corrupted Innodb Tablespace and it is finally done now. As this was over than 1TB worth of data we really tried to avoid dumping the data and find some other way to recovery. Examining Innodb page content and crash information we figured out it should be page of [...]
Wishes for mysqldump
May 22, 2007 By 19 Comments
Dealing with dumping and recovery of large and partially corrupted database I’ve got couple of feature ideas for mysqldump or similar tool and appropriate import tool Dump in parallel single thread dump is not efficient of course especially on systems with multiple CPUs and disks. It is lesser issue in recovery case because import takes [...]
Beware: key_buffer_size larger than 4G does not work
February 14, 2007 By 17 Comments
I was working with customer today which has MySQL on a system with some 64GB or RAM running MyISAM, so they set key_buffer_size to 16G… and every few days MySQL crashes. Why ? Because key_buffer_size over 4GB in size is not really supported (checked with latest and greatest MySQL Enterprise 5.0.34). It works just fine [...]
MySQL Server Memory Usage
May 17, 2006 By 21 Comments
Every so often people ask me the question how should they estimate memory consumption by MySQL Server in given configuration. What is the formula they could use. The reasons to worry about memory usage are quite understandable. If you configure MySQL Server so it uses too small amount of memory it will likey perform suboptimally. [...]
