August 29, 2014

Impact of the number of idle connections in MySQL

Be careful with my findings, I appear to have compile in debug mode, I am redoing the benchmarks. Updated version here. I recently had to work with many customers having large number of connections opened in MySQL and although I told them this was not optimal, I had no solid arguments to present. More than […]

Percona Server 5.1.49-rel11.3

Dear Community, Percona Server version 5.1.49-rel11.3 is now available for download. The changes in this release include: New features Percona Server 5.1.49-rel11.3 is based on MySQL 5.1.49. A new variable was introduced: innodb_use_sys_stats_table. If ON, the table’s statistics are stored statically in the internal table SYS_STATS. The table is populated with the ANALYZE TABLE command. […]

mysql-proxy, urgh performance and scalability ?

For one our project I needed proxy solution, and mysql-proxy is one of well-known, so it was logical first choice. The obvious question which come in mind is what performance penalty we have using mysql-proxy, version 0.7.1. So it is easy to test. (By the way sysbench recently was pushed to Launchpad, see lp:sysbench, and […]

MySQL and IBM

No, this is not about Sun and IBM This is about MySQL. If you download latest 5.1.33 source code you may find there storage/ibmdb2i directory, which obviously is IBM DB2 related. Interesting that there is no mentioning of new engine in Announcement http://dev.mysql.com/doc/refman/5.1/en/news-5-1-33.html. Quick look into source code says

Also interesting that license of […]

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 […]

Faster MySQL failover with SELECT mirroring

One of my favorite MySQL configurations for high availability is master-master replication, which is just like normal master-slave replication except that you can fail over in both directions. Aside from MySQL Cluster, which is more special-purpose, this is probably the best general-purpose way to get fast failover and a bunch of other benefits (non-blocking ALTER […]

MySQL 5.1 went to GA. Was it a good move ?

MySQL 5.1 release as “GA” seems to be the most controversial to date. It had very negative response from Monty, original MySQL Founder and controversial responses in community including another beating by Kevin Burton. There is also very interesting reading on MySQL 5.1 open bugs So how do I take it and where do I […]

Reading MySQL Enterprise future…

Well, actually it is not reading future, but just mysql-5.1.30.rhel4.spec file from MySQL RedHat 4 SRPM. I found there few MySQL Enterprise Editions, namely: MySQL Enterprise Server – Advanced Edition MySQL Enterprise Server – Pro Edition MySQL Enterprise Server – Classic Edition What is difference ? Let’s see. For MySQL Enterprise Server – Advanced Edition: […]

The MySQL optimizer, the OS cache, and sequential versus random I/O

In my post on estimating query completion time, I wrote about how I measured the performance on a join between a few tables in a typical star schema data warehousing scenario. In short, a query that could take several days to run with one join order takes an hour with another, and the optimizer chose […]

TPC-H Run on MySQL 5.1 and 6.0

We were doing MySQL Performance evaluation on TPC-H queries for the client and they kindly allowed us to publish results which are very interesting. This is obviously not audited TPC-H run, and it can’t be because we used MyISAM tables which are not ACID complaint. Plus we only measured Power to keep things simple. We […]