April 17, 2014

Tools and tips for analysis of MySQL’s Slow Query Log

MySQL has a nice feature, slow query log, which allows you to log all queries that exceed a predefined about of time to execute. Peter Zaitsev first wrote about this back in 2006 – there have been a few other posts here on the MySQL Performance Blog since then (check this and this, too) but […]

Open Source Appreciation Day at the Percona Live MySQL Conference

I am very pleased to announce a new event in conjunction with the Percona Live MySQL Conference and Expo this year: Open Source Appreciation Day on Monday, March 31st in the Santa Clara Convention Center! We are pleased to announce two separate groups holding events this year under this new umbrella. We are hosting an […]

Introducing backup locks in Percona Server

TL;DR version: The backup locks feature introduced in Percona Server 5.6.16-64.0 is a lightweight alternative to FLUSH TABLES WITH READ LOCK and can be used to take both physical and logical backups with less downtime on busy servers. To employ the feature with mysqldump, use mysqldump –lock-for-backup –single-transaction. The next release of Percona XtraBackup will […]

Many-table joins in MySQL 5.6

I recently worked on an uncommon slow query: less than 100 rows were read and returned, the whole dataset was fitting in memory but the query took several seconds to run. Long story short: the query was a join involving 21 tables, running on MySQL 5.1. But by default MySQL 5.1 is not good at […]

Oracle’s Mats Kindahl to weave MySQL Fabric into Percona Live session

MySQL Fabric is an integrated framework for managing farms of MySQL servers with support for both high-availability and sharding. Its development has been spearheaded by Mats Kindahl, senior principal software developer in MySQL at Oracle. Mats is leading the MySQL Scaling and High-Availability effort covering the newly released MySQL Fabric and the MySQL Applier for […]

How to avoid common (but deadly) MySQL development mistakes

MySQL software developers are under pressure to do more in less time and create applications that adapt to ever-changing requirements. And it’s true that some of a developer’s time is wasted when his or her method of optimizing involves trying every combination of code and index definition. There is a better way. And next Wednesday […]

How rows_sent can be more than rows_examined?

When looking at queries that are candidates for optimization I often recommend that people look at rows_sent and rows_examined values as available in the slow query log (as well as some other places). If rows_examined is by far larger than rows_sent, say 100 larger, then the query is a great candidate for optimization. Optimization could […]

DBA 101: Sometimes forgotten functionality in the MySQL client

The MySQL client has some functionalities some of us never use. Why would you use them and what is the added value of this? Every DBA and developer has had a moment when he or she needs to connect to a MySQL database using the command line tool. Therefore I’ve written down an explanation of […]

Percona XtraDB Cluster performance monitoring and troubleshooting

First of all we would like to thank all of you who attended the Feb. 19 MySQL webinar, “Performance Monitoring and Troubleshooting of Percona XtraDB Cluster.” We got some really good questions – many of which we didn’t have time to address during the sessions, so Johan Andersson, Severalnines CTO,and I are answering them here […]

The MySQL ARCHIVE storage engine – Alternatives

In my previous post I pointed out that the existing ARCHIVE storage engine in MySQL may not be the one that will satisfy your needs when it comes to effectively storing large and/or old data. But are there any good alternatives? As the primary purpose of this engine is to store rarely accessed data in disk […]