April 24, 2014

MySQL Partitioning – can save you or kill you

I wanted for a while to write about using MySQL Partitioning for Performance Optimization and I just got a relevant customer case to illustrate it. First you need to understand how partitions work internally. Partitions are on the low level are separate table. This means when you’re doing lookup by partitioned key you will look […]

Mass killing of MySQL Connections

Every so often I run into situation when I need to kill a lot of connections on MySQL server – for example hundreds of instances of some bad query is running making server unusable. Many people have special scripts which can take the user, source host or query as a parameter and perform the action. […]

Percona Live 2014 behind; MySQL ahead

I started using MySQL 11 years ago.  That’s not too long compared to other people in the industry, but nonetheless here’s my perspective on the state of the MySQL industry after attending Percona Live MySQL Conference & Expo 2104. In short, the attitude around MySQL has changed from “Does it work?” to “Is it fast […]

How to find bugs in MySQL

Finding bugs in MySQL is not only fun, it’s also something I have been doing the last four years of my life. Whether you want to become the next Shane Bester (who is generally considered the most skilled MySQL bug hunter worldwide), or just want to prove you can outsmart some of the world’s best […]

MySQL performance optimization: Don’t guess! Measure with Percona Cloud Tools

In our practice we often see that MySQL performance optimization is done in a sort of “black magic” way. A common opinion is: “If there is a performance problem – then it must be a database issue, because what else could it be? And if this is a database issue, then it must involve IO […]

MySQL server memory usage troubleshooting tips

There are many blog posts already written on topics related to “MySQL server memory usage,” but nevertheless there are some who still get confused when troubleshooting issues associated with memory usage for MySQL. As a Percona support engineer, I’m seeing many issues regularly related to heavy server loads – OR OOM killer got invoked and […]

FOSDEM 2014: MySQL And Friends Community Dinner

FOSDEM is coming to town again here in Brussels this February 1-2, and as usual, there is a MySQL Devroom. Traditionally, a MySQL and Friends community dinner is also held during the event and this year is no different – we’ve organized one for Saturday, February 1 from 8:30 p.m. to 11:30 p.m. (CET). If you […]

[ERROR] mysqld: Sort aborted: Server shutdown in progress

Recently, one of our support customers faced this: “[ERROR] mysqld: Sort aborted: Server shutdown in progress.” At first it would appear this occurred because of a mysql restart (i.e. the MySQL server restarted and the query got killed during the stopping of mysql). However, while debugging this problem I found no evidence of a MySQL […]

MySQL Error: Too many connections

We have always received quite few questions here at Percona Support on how to avoid the dreaded “Too many connections” error, as well as what is the recommended value for max_connections. So, in this article I will try to cover best possible answers to these questions so others can mitigate similar kinds of issues. My […]

Handling long-running queries in MySQL with Percona XtraBackup

I recently had a case where replication lag on a slave was caused by a backup script. First reaction was to incriminate the additional pressure on the disks, but it turned out to be more subtle: Percona XtraBackup was not able to execute FLUSH TABLES WITH READ LOCK due to a long-running query, and the […]