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 [...]
How to recover deleted rows from an InnoDB Tablespace
February 20, 2012 By 1 Comment
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 [...]
Why don’t our new Nagios plugins use caching?
February 19, 2012 By Leave a Comment
In response to the release of our new MySQL monitoring plugins on Friday, one commenter asked why the new Nagios plugins don’t use caching. It’s worth answering in a post rather than a comment, because there is an important principle that needs to be understood to monitor servers correctly. But first, some history. When I [...]
Announcing MySQL Monitoring Plugins from Percona
February 17, 2012 By 18 Comments
We’ve released a new set of monitoring plugins for MySQL servers and related software. With these plugins, you can set up world-class graphing and monitoring for your MySQL servers, using your own on-premises Cacti and Nagios software. The Cacti plugins are derived from an existing set of templates we’ve been using for several years, but [...]
Optimize Your SQL With Percona’s Online Query Advisor!
February 15, 2012 By 23 Comments
Wouldn’t it be nice if you could get expert advice on your SQL queries to find problems in them, the same way that programmers can use lint-check tools to warn about bugs in their C? if ( execute = 1 ) { launch_missile(); } Such a simple mistake, but it’s the kind of thing that [...]
Troubleshooting MySQL Upgrade Performance Regressions
February 15, 2012 By Leave a Comment
So lets say you upgraded from MySQL 5.1 to Percona Server 5.5 and instead of expected performance improvement you see your performance being worse. What should you do ? First if you followed MySQL upgrade best practices such as testing your workload with pt-upgrade the chances of this happening are rather slim. But lets assume [...]
Why not make a tool to improve existing configurations?
February 10, 2012 By 4 Comments
A couple of users of our very popular MySQL Configuration Wizard have submitted feedback such as “I’d love to input my existing server settings and get suggestions on how to improve it.” This sounds like it would be great, doesn’t it? We’ve considered doing this, and even partially implemented it. But during our pre-release testing, [...]
Announcing Percona Toolkit Release 2.0.3
February 6, 2012 By 2 Comments
We’ve released Percona Toolkit 2.0.3, with a couple of major improvements and many minor ones. You can download it, read the documentation, and get support for it. What’s new? You can read the changelog for the details, but here are the highlights: Brand new pt-diskstats, thanks to Brian Fraser. This tool is completely rewritten, and [...]
STOP: DELETE IGNORE on Tables with Foreign Keys Can Break Replication
February 2, 2012 By 1 Comment
DELETE IGNORE suppresses errors and downgrades them as warnings, if you are not aware how IGNORE behaves on tables with FOREIGN KEYs, you could be in for a surprise. Let’s take a table with data as example, column c1 on table t2 references column c1 on table t1 – both columns have identical set of rows for [...]
Verifying backup integrity with CHECK TABLES
February 1, 2012 By 4 Comments
An attendee to Espen’s recent webinar asked how to check tables for corruption. This kind of ties into my recent post on InnoDB’s handling of corrupted pages, because the best way to check for corruption is with CHECK TABLES, but if a page is corrupt, InnoDB will crash the server to prevent access to the [...]
