October 24, 2014

OOM relation to vm.swappiness=0 in new kernel

I have recently been involved in diagnosing the reasons behind OOM invocation that would kill the MySQL server process. Of course these servers were primarily running MySQL. As such the MySQL server process was the one with the largest amount of memory allocated. But the strange thing was that in all the cases, there was […]

Percona Live MySQL Conference Highlights

The Percona Live MySQL Conference and Expo 2014 was March 31st through April 4th in Santa Clara, California. I heard numerous positive comments from attendees and saw even more on social media. Our conference team lead by Kortney Runyan pulled together a smooth, enjoyable event which made it easy for attendees to focus on learning […]

Percona Server 5.6.16-64.0 with TokuDB engine now available

Percona is glad to announce the first ALPHA release of Percona Server 5.6.16-64.0 with TokuDB engine on March 3rd, 2014. Downloads are available here and from the Percona Software Repositories. Based on Percona Server 5.6.16-64.0 including all the features and bug fixes in it, and on TokuDB 7.1.5-rc.3, Percona Server 5.6.16-64.0-tokudb is the first ALPHA […]

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 […]

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 […]

Increasing slow query performance with the parallel query execution

MySQL and Scaling-up (using more powerful hardware) was always a hot topic. Originally MySQL did not scale well with multiple CPUs; there were times when InnoDB performed poorer with more  CPU cores than with less CPU cores. MySQL 5.6 can scale significantly better; however there is still 1 big limitation: 1 SQL query will eventually use only […]

Innotop: A real-time, advanced investigation tool for MySQL

GUI monitoring tools for MySQL are not always suitable for all our needs or situations. Most of them are designed to provide historical views into what happens to our database over time rather then real-time insight into current MySQL server status. Excellent free tools for this include Cacti, Zabbix, Ganglia, Nagios, etc. But each of […]

Your troubles are over, pt-heartbeat 2.1

Poor pt-heartbeat 2.1: it was perfectly fine through Percona Toolkit 2.1.7, but it’s had a rough life since. Its troubles are finally over as of Percona Toolkit 2.1.10. At a conference recently, a user joked to me that “Percona Toolkit is awesome, but you really broke pt-heartbeat.” It’s true, and if you haven’t heard or […]

Percona Server 5.5.32-31.0 now available

Percona is glad to announce the release of Percona Server 5.5.32-31.0 on July 2nd, 2013 (Downloads are available here and from the Percona Software Repositories). Based on MySQL 5.5.32, including all the bug fixes in it, Percona Server 5.5.32-31.0 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release […]

MySQL Query Patterns, Optimized – Webinar questions followup

On Friday I gave a presentation on “MySQL Query Patterns, Optimized” 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 time for  during the session, but here […]