I have been working on a new assignment this week, with the goal to improve performance in a .NET application using MySQL (3.21) for data storage. The application handles a lot of data in what is basically a single user system.

The main rason for the performance problems was heavy searches where indexes did not match. Simply switching the order of columns in the composite key fixed most of it.

In the old version they copied data to a temporary table, to solve the slow query problem. Once we had the indexes fixed, we could drop this solution and use the ase table in all cases. This also speeded it up a lot.

The change to MySQL 5.0 made a few other changes possible
- switch to shared memory for communication between database and application
- buffering of indexes
- query caching
which all ment further improved performance

All in all quite successful so far. …

Even though the conference is long over, I still have unpublished notes sitting on my ~/Desktop, and it only makes sense that I clean it out. These are notes from Ed Presz’s session, titled For Ticketmaster, MySQL Replication is the Ticket! They are as always, pretty raw.

We were all given a handout, which was some corporate spiel, which contained a lot of information about hiring. Their mission is to “sell more tickets better than anyone in the event business, worldwide”.

I found it impressive to note that Ticketmaster managed last year’s Melbourne Commonwealth ticket sales. I guess, even more impressive is that for next year’s Beijing Olympics, Ticketmaster ran a ticket lottery, and 17,843 seat tickets were sold in 75 seconds!

MySQL 4.0.18 is currently used, and they …

The MySQL UDF Repository is moving forward! Although it was only recently launched we've been contacted by quite a few interested parties already.

For example, the MySQL Repository has been mentioned by Ronald Bradford in this week's Logbuffer, the "Carnival of the Vanities" hosted by the Pythian Group. Thanks Ronald!

To facilitate the community process, we've set up a Google Group. The …

Interested in the XPath support in MySQL 5.1?

I have done a little with XPath over the years, but I've never spent that much time learning it in any detail. Since we have added XPath 1.0 support I'd thought I would site back and and learn a bit more about it.

For an excellent Tutorial that covers all of the basics of node discovery it is best to first read:
http://www.zvon.org/xxl/XPathTutorial/General/examples.html

If you only read one tutorial, this is the one to read. It will get you through all of the basics of finding nodes and searching in deeply nested XML documents. I particularly liked this tutorial since the author had went through a lot of trouble to visually explain the results of XPath queries.
…

In my last post I reviewed how to create a test case using multiple connections and it is quickly apparent that keeping track of concurrent connections within test cases is difficult and error prone. Creating a tool to make test case writing easier and more automated is the goal of my Summer of Code project. To start, I have looked at the test facilities of PostgreSQL.

PostgreSQL and their documentation on their test framework was short, but it seems they have a regression test suite to test the functionality of their code.

http://www.postgresql.org/docs/7/static/regress.htm

They use a directory of .sql files that are executed against their database and the results, like MySQL, are compared against an file with the expected result. The tests can be run sequentially or parallel like the MySQL tests but overall their framework …

If I recall correctly, I saw a post about Amp'd Mobile going bankrupt, but now that I wanted to read it, it's gone. So how can this be? I thought they were doing really good especially since they were one of the winners at this year's MySQL Application of the year. I wonder what went wrong.

UPDATE:
The official statement from Ampd Mobile:

"As a result of our rapid growth, our back-end infrastructure was unable to keep up with customer demand. We are taking this step as a necessary and responsible action to sustain and strengthen our momentum in the market place".

Ok, Now I am really curious. Which part of backend? Network? Application? Storage? ... Database?

And whatever these backend scalability issues were, why weren't they actively resolved? Could making a company scalable drive it bankrupt? If not, then …

Are you using the mysql-5.1-backup-prototype clone on http://mysql.bkbits.net/?
We recently fixed this clone by removing a changeset, so you need to reclone this if you are using it. Sorry for the inconvenience.  (By the way, if you use this clone, let us know what you think about it…)
More information about the Online Backup project is on MySQL Forge: http://forge.mysql.com/wiki/OnlineBackup

This is not strictly speaking about open source, but for anyone running a new Windows machine, it's a big issue.  PC Decrapifier is a free software which helps remove all the "craplets" (crippleware applications) that are installed when you buy a new PC.  Kudos to Walt Mossberg from the Wall Street Journal for helping to fight the fight against crapware.

"The problem is a lack of respect for the consumer. The manufacturers don?t act as if the computer belongs to you. They act as if it is a billboard for restricted trial versions of software and ads for Web sites and services that they can sell to third-party companies who want you to buy these products."

One …

And then there were two (software patent deals with Microsoft). Today, Xandros made its first newsworthy announcement in 10 years and indicated it has capitulated to Microsoft. I love how Microsoft tries to blur the lines between its patent folderol and interoperability agreements (notice how it tries to obscure this in the press release, talking about Novell, Xandros, XenSource (no patent agreement), JBoss (no patent agreement), Zend (no patent agreement), etc. They talk about them all as if they're the same thing, but they're not. The smart companies are buying into interoperability, not FUD. Yet Bill Hilf persists:Customers win when... READ MORE

Some applications require direct access to a block device, without an intermediate file system. Some Oracle and MySQL configurations are an example, as are some Xen setups, or IET. Can you do this with DRBD? Sure you can.

However, you need to fulfill two prerequisites:

1. Your application can’t access DRBD while it’s in the Secondary role. So, you must make sure DRBD is Primary before your application attempts using that device.
2. The user in whose context your application runs needs read/write access to that device.

Your cluster manager, when configured properly, normally takes care of item #1 for you. #2 is a little trickier:
Normally, DRBD’s device nodes are owned by root:disk, with permission bits set to 0660 (rw-rw----). So in order to allow your application to use the device, you have two options:

• Add …