We often encounter customers who have partitioned their applications among a number of databases within the same instance of MySQL (think application service providers who have a separate database per customer organization … or wordpress-mu type of apps). For example, take the following single MySQL instance with multiple (identical) databases:
Introduction When people think about Perconaâ€™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 […]
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
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. […]
Whilst working with a client recently I noticed a large number of temporary tables being created on disk.
show global status like 'Created_tmp%'
| Created_tmp_disk_tables | 91970 |
| Created_tmp_files | 19624 |
| Created_tmp_tables | 1617031 |
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 whatâ€™s even more important the patch is available for all the recent MySQL releases. To remind anyone who has not yet come across this […]
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 […]
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 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 […]
Just short message that patch enables microsecond resolution in slow-log (see more http://www.percona.com/blog/2006/09/06/slow-query-log-analyzes-tools/) for 5.0.37 is available here: www.percona.com/blog/files/patches/patch.slow-micro.5.0.37.diff The patch for 5.0.41 : www.percona.com/blog/files/patches/patch.slow-micro.5.0.41.diff
I just filed a bug regarding slow queries executed by replication thread are not being logged to the slow query log. This is not a big deal but it is ugly little gotcha which I think few people know about. It is especially bad if you’re using tools to analyze slow query log to find […]