I've had a very good day today.
I don't stop and think and say that to myself very often.

Despite all the driving, sitting, bad spicy food and me voluntarily suffering while pretending I can be a vegetarian, I feel that it was a day worth to live.

In the morning we had to drive over 90 miles to Linuxfest Northwest 2007 and despite long distance and apparent unimportance of the conference it was just the right kind of American experience I like to have.

People were coming there with their kids to listen to talks about Zope and Python and find out more about basics of the General Public License. Presenters whose profile seemed to be too high for this conference, like BrianA and BradFitz seemed to be at home and at ease. Seeing these two kinds together is part of the American society I've always been pleased with.

Nothing …

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.

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.