db – Grey Panthers Savannah

Database links

gpanther — Wed, 29 Apr 2009 07:46:00 +0000

Via the MySQL performance blog: the Percona 2009 conference posted the slides (most of them anyways). There is some very good and diverse material in there (not necessarily MySQL specific). I also found the following link in one of the presentations: http://omniti.com/does/postgresql – love it!

Testing Disk Speed: the dd Test – I/O is the bottleneck in a well-designed DB, so it is important to know how far you can stretch. Along the same lines of database testing we have Database Test 2, a series of test. There are some interesting benchmarks related to different configuration options with different filesystems. Of course, you should do your own testing, but this is a good starting point.

Finally, there are some issues with iotop, but it still helped be in tracking down the fact that when I upgraded to Ubuntu Jaunty (9.04), the indexer got reactivated and it was stressing the harddrive of my machine.

Picture taken from LindaH’s photostream with permission.

Weird Sybase JDBC driver issue (jConnect)

gpanther — Thu, 16 Apr 2009 15:19:00 +0000

I post this so that the search engines can pick up on it and maybe it can help somebody out. I had the following issue with the Sybase JDBC driver (jConnect):

I was calling a stored procedure and it was throwing an error. However these errors weren’t propagated to the Java code in form of SQLExceptions, as I was expecting. Things which solved the problem:

Using .executeUpdate() instead of .execute()
Using PreparedStatement instead of CallableStatement
Using the jTDS open-source driver instead of jConnect

None of the solutions are ideal and some are actually counter-intuitive (why should it make a difference if I use .executeUpdate instead of .execute? – the later should be a more generic version of the former). I’m by no means a JDBC expert, so I posted it on stackoverflow.

PS. This is an other reason for using open-source: with it you can at least step trough the code without using tools like JadEclipse (which is a very nice tool btw for decompiling your classes directly from your IDE without any fuss).

Random Database Blogging

gpanther — Tue, 03 Feb 2009 11:27:00 +0000

From the Database and Performance blog: Queuing Theory & Resource Utilization – a lightweight introduction into the field which explains why you don’t have linear growth all the way – at a moment you hit a magic ceiling and things get much worse.

PostgreSQL Replicator is an other way to replicate your PostgreSQL database. Now it has rpm’s built automatically for it by the pgsqlrpms project. This makes it easier to try it out certainly. Now if we could have some .deb’s please

A brief comparison between londiste and slony.

The perils of InnoDB with Debian and startup scripts – something useful to read about if you are using MySQL + Debian.

Initial ext3 vs ext4 Results – this looks awesome. Together with PostgreSQL 8.4 this should rock!

An other benchmark comparing different scheduling algorithms under Linux for use with a DB – this is why I like Linux! You can tune it to your hearts will. With closed source you have to trust that the vendor made the correct choice.