November 21, 2014

The story of one MySQL Upgrade

I recently worked on upgrading MySQL from one of very early MySQL 5.0 versions to Percona Server 5.1. This was a classical upgrade scenario which can cause surprises. Master and few slaves need to be upgraded. It is a shared database used by tons of applications written by many people over more than 5 years […]

Slow Query Log analyzes tools

(There is an updated version of this post here). MySQL has simple but quite handy feature – slow query log, which allows you to log all queries which took over define number of seconds to execute. There is also an option to enable logging queries which do not use indexes even if they take less […]

MySQL Crash Recovery

MySQL is known for its stability but as any other application it has bugs so it may crash sometime. Also operation system may be flawed, hardware has problems or simply power can go down which all mean similar things – MySQL Shutdown is unexpected and there could be various inconsistences. And this is not only […]

MySQL Query Cache

MySQL has a great feature called “Query Cache” which is quite helpful for MySQL Performance optimization tasks but there are number of things you need to know. First let me clarify what MySQL Query Cache is – I’ve seen number of people being confused, thinking MySQL Query Cache is the same as Oracle Query Cache […]

MySQL EXPLAIN limits and errors.

Running EXPLAIN for problematic queries is very powerful tool for MySQL Performance optimization. If you’ve been using this tool a lot you probably noticed it is not always provide adequate information. Here is list of things you may wish to watch out. EXPLAIN can be wrong – this does not happen very often but it […]

Percona Toolkit 2.2.3 released; bug fixes include pt-online-schema-change

Among all of the excellent events going on like YAPC, Velocity, and Percona MySQL University, we recently released Percona Toolkit 2.2.3. It’s a small update that includes the following: pt-online-schema-change did not handle the failure of the DROP TRIGGER statements correctly Created pt-agent pt-query-digest –output json now includes more data The pt-online-schema-change issue had a high importance. […]

Percona Toolkit Webinar followup Q&A

First, a thank you to everyone who attended the webinar Today, I appreciate your time and nice comments. As promised, here are answers to questions that couldn’t be answered during the talk:   Q: How do you install the tools? The manual has full details, but it’s important to know that the latest release for […]

Faster Point In Time Recovery with LVM2 Snaphots and Binary Logs

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 […]

Percona Toolkit 2.0.1 and 1.0.2 released

I’m happy to announce that we’ve released Percona Toolkit 2.0.1, a major new version of our essential DBA toolkit, as well as a minor bugfix update to the old 1.0.x series. You can download it from the project homepage, or install it through our RPM and DEB repositories. Documentation is online (and the 1.0 docs […]