Domas Mituzas (who works for MySQL AB and works with Wikipedia) has published a workbook (pdf) about about the design and architecture of Wikipedia.

Expect to see lots of common infrastructure tools used in common across sites like Livejournal, Digg, etc.

Basically, everyone is using about the same core technology:

Started as Perl CGI script running on single server in 2001, site has grown into distributed
platform, containing multiple technologies, all of them open. The principle of openness
forced all operation to use free & open-source software only. Having commercial alterna-
tives out of question, Wikipedia had the challenging task to build efficient platform of freely
available components.

With all the talk lately of the new INFORMATION_SCHEMA plugin API, I thought I’d have a go at making a couple. I’ve now made three different pluggable INFORMATION_SCHEMA tables - one that works from df -k - which will only work on UNIX like systems (other than AIX or HPUX) - and two which integrate the SIGAR library available from Hyperic.

I’ll post the df -k plugin in a couple of days, however I wanted to get the two I have created based on the SIGAR library ‘out to the world’ for some feedback on them! They are currently a very rough prototype (they need a little more work on return checking etc.!) - however they are currently functional.

There are two INFORMATION_SCHEMA tables within the plugin library - INFORMATION_SCHEMA.OS_STATUS and …

I recorded many of the sessions I attended at the conference. You can download the audio files in Ogg Vorbis format from this article. These files will not stay up forever -- I will probably remove them after a few weeks.

Performance-wise, the idea of Prepared Statements is that the server does certain pre-processing on PREPARE command, and then those steps are omitted when the statement is executed. If the statement is executed several times, we get an economy of

cost_of_prepare_preprocessing * (#statement_executions - 1)

This makes one want to move the CPU and IO-intensive query optimization into the PREPARE phase. Unfortunately, this will make the optimizer work much worse - optimizer's decisions are based on the external information, and there is much less available information at PREPARE phase. The most crucial differences are that

• The values of the '?' parameter markers are not yet known
• The results of probes done in the the queried tables cannot be relied on because the table data may change before the EXECUTE
• [less important] Table and index statistics may change before the EXECUTE

…

Jonathon Coombes recently blogged in MySQL Cluster Certified that he passed the MySQL Cluster DBA Certification as was the first Australian. Lucky for him I passed the exam after my presentation on the second day of the conference. I guess us Australian’s are leading the world!

As Jonathon said it was rather hard, certainly more difficult then the other DBA exams but nothing for an experienced Cluster DBA.

Today someone sent me an exploit for the Windows version of XAMPP: Using our xampp/adodb.php and a buffer overflow vulnerability in mssql_connect() the exploit is able to call arbitrary(!) commands on the targeted system.

If you secured your system as described in our manual, you're a lucky guy and your system is not affected by this vulnerability.
If you haven't secured your system, please do it right now!!!

YOU SHOULD USE NDB/BINDINGS WHICH YOU CAN FIND HERE! NDB/BINDINGS IS THE OFFICIAL VERSION BEING MAINTAINED AND INCLUDES NDB/J.

IGNORE EVERYTHING BELOW THIS POINT (except the first couple of sentences):

NDB/J is a type II Java connector that makes it possible for a Java application to connect directly to the NDBCluster storage engine, thus by-passing the MySQL Server.
Initial benchmarks we have conducted shows that NDB/J is in parity with the C++ NDBAPI when it comes to performance. Moreover, NDB/J is a wrapper of the C++ NDBAPI, but offers Java-like abstractions such as Exceptions and ResultSets.

If you are interested in evaluating NDB/J and trying it out, you can download it here.
The following versions of MySQL Cluster should work:

• MySQL …

In my fourth day at the MySQL Conference and Expo 2007, I attended several great sessions, starting with my own.