July 22, 2014

Q&A: Even More Deadly Mistakes of MySQL Development

On Wednesday I gave a presentation on “How to Avoid Even More Common (but Deadly) MySQL Development Mistakes” for Percona MySQL Webinars.  If you missed it, you can still register to view the recording and my slides. Thanks to everyone who attended, and especially to folks who asked the great questions.  I answered as many as we had […]

Why %util number from iostat is meaningless for MySQL capacity planning

Earlier this month I wrote about vmstat iowait cpu numbers and some of the comments I got were advertising the use of util% as reported by the iostat tool instead. I find this number even more useless for MySQL performance tuning and capacity planning. Now let me start by saying this is a really tricky and deceptive number. Many […]

Getting to know TokuDB for MySQL

During last April’s Percona Live MySQL Conference and Expo, TokuDB celebrated it’s first full-year as an open source storage engine. I still remember reading the official announcement and the expectations it created one year ago. The premises were very interesting as it had the potential of helping MySQL manage “big data” in a way InnoDB just […]

Parallel Query for MySQL with Shard-Query

While Shard-Query can work over multiple nodes, this blog post focuses on using Shard-Query with a single node.  Shard-Query can add parallelism to queries which use partitioned tables.  Very large tables can often be partitioned fairly easily. Shard-Query can leverage partitioning to add paralellism, because each partition can be queried independently. Because MySQL 5.6 supports the […]

How to log slow queries on Slave in MySQL 5.0 with pt-query-digest

Working as a Percona Support Engineer, every day we are seeing lots of issues related to MySQL replication. One very common issue is slave lagging. There are many reasons for slave lag but one common reason is that queries are taking more time on slave then master. How to check and log those long-running queries?  From […]

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 […]

Generating test data for MySQL tables

One of the common tasks requested by our support customers is to optimize slow queries. We normally ask for the table structure(s), the problematic query and sample data to be able to reproduce the problem and resolve it by modifying the query, table structure, or global/session variables. Sometimes, we are given access to the server […]

10 MySQL settings to tune after installation

When we are hired for a MySQL performance audit, we are expected to review the MySQL configuration and to suggest improvements. Many people are surprised because in most cases, we only suggest to change a few settings even though hundreds of options are available. The goal of this post is to give you a list […]

Analyzing WordPress MySQL queries with Query Analytics

This blog, MySQLPerformanceBlog.com, is powered by WordPress, but we never really looked into what kind of queries to MySQL are used by WordPress. So for couple months we ran a Query Analytics (part of Percona Cloud Tools) agent there, and now it is interesting to take a look on queries. Query Analytics uses reports produced […]

MySQL 5.7.3 milestone release fixes some of my pet peeves

It is wonderful to see some of my original pet peeves fixed in MySQL 5.7.3! It has not even taken 10 years I remember when starting my work at MySQL Support that I would recommend using UNION ALL instead of plain UNION because it would not require duplicate elimination, and as such, would not require […]