April 24, 2014

Why Swapping is bad for MySQL Performance ?

So you get MySQL or other applications using too much memory on the box or OS behaving funny and using more memory for cache and pushing application to the swap. This causes swapping and causes performance problems. This much is obvious. But how bad is it ? Should you count it same as normal Disk […]

Should you have your swap file enabled while running MySQL ?

So you’re running dedicated MySQL Linux box with plenty of memory, so the good question arises if you should have swap file enabled or disable it ? I’ve seen production successfully running on boxes both with and without swap file so it is not the question of you must do it this or that way […]

How to monitor ALTER TABLE progress in MySQL

While working on a recent support issue as a Percona Support Engineer,  I got one question from a customer asking how to monitor ALTER TABLE progress. Actually, for MySQL 5.5 and prior versions, it’s quite difficult to ALTER the table in a running production environment especially for large tables (with millions records). Because it will rebuild and lock the table […]

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 […]

Linux performance tuning tips for MySQL

Because most MySQL production systems probably run on Linux, I’ve decided to place the most important Linux tuning tips that will help improve MySQL performance. There is nothing new here, most of them are well known, however, I’ve decided to collect those Linux configuration tips into 1 blog post. Filesystem ext4 (or xfs), mount with […]

High-availability options for MySQL, October 2013 update

The technologies allowing to build highly-available (HA) MySQL solutions are in constant evolution and they cover very different needs and use cases. In order to help people choose the best HA solution for their needs, we decided, Jay Janssen and I, to publish, on a regular basis (hopefully, this is the first), an update on […]

Schema changes – what’s new in MySQL 5.6?

Among many of the improvements you can enjoy in MySQL 5.6, there is one that addresses a huge operational problem that most DBAs and System Administrators encounter in their life: schema changes. While it is usually not a problem for small tables or those in early stages of product life cycle, schema changes become a […]

Choosing a MySQL HA Solution – Post-Webinar Q&A

Thanks to everyone who was in attendance on 05 June 2013 for my “Choosing a MySQL HA Solution” webinar. If you weren’t able to make it but are interested in listening to the presentation, it’s currently up and available for viewing over at percona.com. My apologies if we weren’t able to get to your question […]

The write cache: Swap insanity tome III

Swapping has always been something bad for MySQL performance but it is even more important for HA systems. It is so important to avoid swapping with HA that NDB cluster basically forbids calling malloc after the startup phase and hence its rather complex configuration. Probably most readers of this blog know (or should know) about […]