July 29, 2014

Logging MySQL queries from the client instead of the server

The “slow query log” is the single most valuable way to examine query execution on your MySQL server. Queries are logged with timing information, and in the case of Percona Server, a great deal of additional performance and other diagnostic information. But the execution time recorded in the log is the time the query took […]

Storing MySQL Binary logs on NFS Volume

There is a lot of discussions whenever running MySQL storing data on NFS is a good idea. There is a lot of things for and against this and this post is not about them. The fact is number of people run their databases on NetApp and other forms of NFS storage and this post is […]

Impact of logging on MySQL’s performance

Introduction When people think about Percona’s microslow patch immediately a question arises how much logging impacts on performance. When we do performance audit often we log every query to find not only slow queries. A query may take less than a second to execute, but a huge number of such queries may significantly load a […]

Poor man’s query logging

Occasionally there is a need to see what queries reach MySQL. The database provides several ways to share that information with you. One is called general log activated with

(or

in MySQL 5.1+) start-up parameter. The log writes any query being executed by MySQL to a file with limited amount of additional information. […]

Updated msl (microslow) patch, installation walk-through!

For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and what’s even more important the patch is available for all the recent MySQL releases. To remind anyone who has not yet come across this […]

Be careful rotating MySQL logs

If you enable logging of all queries as “slow queries” using the patch or MySQL 5.1 you can get log file to grow huge. Same may happen with general log file. In some cases we’ve got log file sizes of 100G or more which may need to be cleaned up. Here is some danger waiting […]

Enabling/Disabling query log without server restart in MySQL 5.0

General query logging can be very handy in MySQL on profuction server for various debugging needs. Unfortunately you can’t switch it on and off without restarting server until MySQL 5.0. What can you do in MySQL 5.0 and below ? Use Our Patch – With this patch you can get all queries logged as slow […]

Guess what?! Microsecond slow query timing finally available in MySQL!

Vadim asked me yesterday to update Microslow patch for 5.1.21, because the previous one I wrote for 5.1.20 failed to apply correctly on the new MySQL release. Imagine the expression on my face after I unpacked the sources and found out that MySQL incorporated the patch to their release. So it’s a built-in feature now […]

Microslow patch for 5.1.20

Microslow patch has been there for some time, but only for earlier MySQL editions such as 4.1 and 5.0. Now it’s also available for the latest 5.1. Because MySQL went through a lot of internal changes, the patch had to be written from scratch. It introduces some minor change in existing functionality and also adds […]

Microslow patch for 5.0.37

Just short message that patch enables microsecond resolution in slow-log (see more http://www.mysqlperformanceblog.com/2006/09/06/slow-query-log-analyzes-tools/) for 5.0.37 is available here: www.mysqlperformanceblog.com/files/patches/patch.slow-micro.5.0.37.diff The patch for 5.0.41 : www.mysqlperformanceblog.com/files/patches/patch.slow-micro.5.0.41.diff