Search Results for: slow log

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. […]

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 […]

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 […]