LVM snapshots is one powerful way of taking a consistent backup of your MySQL databases – but did you know that you can now restore directly from a snapshot (and binary logs for point in time recovery) in case of that ‘Oops’ moment? Let me show you quickly how. This howto assumes that you already [...]
DBD::mysql 4.014 breaks pt-table-checksum 2.0. The cause is unknown, but the effect is a lot of errors like: DBD::mysql::st execute failed: called with 2 bind variables when 6 are needed [for Statement "..." with ParamValues: ...] at ./pt-table-checksum line 7216. The fix is simple: upgrade (or even downgrade) DBD::mysql to any version except 4.014. To [...]
In my previous post I explained how it could be possible to recover, on some specific cases, a single table from a full backup in order to save time and make the recovery process more straightforward. Now the scenario is worse because we don’t have a backup or the backup restore process doesn’t work. How [...]
Overview Profiling, analyzing and then fixing queries is likely the most oft-repeated part of a job of a DBA and one that keeps evolving, as new features are added to the application new queries pop up that need to be analyzed and fixed. And there are not too many tools out there that can make [...]
It is no secret that bugs related to multithreading–deadlocks, data races, starvations etc–have a big impact on application’s stability and are at the same time hard to find due to their nondeterministic nature. Any tool that makes finding such bugs easier, preferably before anybody is aware of their existence, is very welcome.
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, [...]
So I’m back from the Percona dev team’s recent meeting. While there, we spent a fair bit of time discussing Xtrabackup development. One of our challenges is that as we add richer features to the tool, we need equivalent testing capabilities. However, it seems a constant in the MySQL world that available QA tools often [...]
Last week I helped 2 different customers with infinite replication loops. I decided to write a blog post about these infinite loop of binary log statements in MySQL Replication. To explain what they are, how to identify them… and how to fix them.
I am very happy to welcome Patrick Crews to the Percona development team. Patrick joins Percona at a very exciting time for the development team. We are getting regular releases of Percona Server and Percona Xtrabackup out the door, we have been heavily using the Jenkins continuous integration system to maintain and improve the quality of [...]
Dealing with MySQL you might need to deal with RAID recovery every so often. Sometimes because of client lacking the proper backup or sometimes because recovering RAID might improve recovery, for example you might get point in time recovery while backup setup only takes you to the point where last binary log was backed up. [...]