Shell Tips ! » Benchmarks

MySQL – Impact of multiple column indexes misuse

Nicolas Brousse — Wed, 13 Feb 2008 11:27:44 +0000

Here is a quick picture about the impact of MySQL indexes misuse. At work, our developers made a new release of their search engine using MySQL fulltext indexes, unfortunately they didn’t implement it correctly. The impact was a huge load on all our database servers. To find the trouble, I had to redirect the SQL search flow to a specific server and check for the slow queries then reproduce it with EXPLAIN. Don’t need a long time to find that the search query did an invalid usage of the fulltext index and the “Match / Against” syntax. In fact, the fulltext index was a multiple column fulltext index, in such case you have to specify ALL the column present in your index, else the index won’t be used by MySQL…

[PHP] Zend Platform – Performance results

Nicolas Brousse — Mon, 12 Nov 2007 16:57:14 +0000

If you are a PHP developer or a LAMP server admin you probably have already heard about the Zend Platform. After some test and configure/tunning step, we deployed this solution on a heavy loaded production server running with Apache 2.x, PHP 4.4.x, MySQL Client 5.x.

The server used for deploy and test the Zend Platform in real production condition is a Bi-Xeon 1,4Ghz with 2Go RAM and 2×36 Go SCSI. This server is part of a cluster made of 10 servers which deliver PHP scripts only. All statics media (gif, css, js, swf, etc.) are delivered thru other dedicated servers.

Statistics Without Zend Platform

More than 3.000.000 Hits/Day

30 Hits/sec

60% Average CPU Load

Statistics With Zend Platform

More than 10.000.000 Hits/Day

100 Hits/sec

20% Average CPU Load

Download the PDF Version

Download the PNG Version

To sum up

Manage 3.5 times more traffic

Having 3 times less load

Use same quantity of process

All the advanced futures for debug, profile, analyze your code

Centralize error message easily from multiple front (With stats, alerts, vhost, etc.)

HTML Caching solution

Of course, all this stuff could be done with xDebug, xCache and many other Open Source solution, this will depend of your free time for deploying it. The Zend Platform is an “All in One” package with some advanced features and a good interaction between the Platform and your IDE (Zend Studio/Neon).

Choosing a filesystem for your Linux/Unix server

Nicolas Brousse — Mon, 27 Aug 2007 18:31:31 +0000

You probably already ask you : “which filesystem can I use on my web servers or database server ?” Usually you will use the well know Ext3-fs but what about the others ?

I will just try to give you some clue about some other common filesystems. The filesystem aspect of your server is really important and your choice will vary with your running application. As exemple, a mail server will have more performances with a Reiserfs filesystem than with Ext3-fs.

You can have a large list of existing filesystems on wikipedia: http://en.wikipedia.org/wiki/Comparison_of_file_systems

An interesting banchmark about Reiser4 : http://www.namesys.com/benchmarks.html

In the case of a MySQL Server you can try to benchmark your own server with the excellent tool SysBench and read this good article on MySQL Website: http://dev.mysql.com/books/hpmysql-excerpts/ch06.html

Here is a complete benchmark done with SysBench with a MySQL Server 4.1 on various filesystems where we can see the High Performance of XFS in a MySQL Environment: http://howto.x-tend.be/MySQL-FileSystems-Benchmark/x45.html

To conclude about filesystems, there is not a “best filesystem”, as any tuning performance aspect on a Linux/Unix box your choice will depend on your workload, your data integrity needing, the requested size, the disk characteristics, journaling needs, etc. Important things is to well understand your server bottleneck (you can use iostat and dd) then you could define your needs and choose your filesystem.

Personnaly, my databases are now running with XFS, my mailservers with ReiserFS and my web servers in Ext3-fs.

NB : Another important point will be to choose the correct schedule, but nowadays the default one is generally the good one (cfq : Completely Fair Queueing. Here is a good (old) post on RedHat web site : http://www.redhat.com/magazine/008jun05/features/schedulers/