Gallery

Programming for kids

Posted on 28 Apr 2009 at 12:02

MySQL fan Ian Wrigley discusses computer programming for children, and goes back in time with linux.

Anyway, when I teach these courses I'm often asked whether MySQL can do this or that obscure operation (often this question will come from Oracle DBAs, as Oracle is a behemoth of a program that can do absolutely anything, no matter how pointless). My answer is often that while MySQL can't do that particular thing on its own, there's a third-party tool available that will enable it to do so, and often that tool is part of an excellent package called Maatkit by the estimable Baron Schwartz, a true MySQL master.

If you're a MySQL DBA and you haven't yet come across Maatkit, you owe it to yourself to check it out. It consists of a collection of utilities that do such things as analyse the slow query log by connection ID, monitor replication slaves and try to restart them in case of errors, monitor the delay in replication of a slave behind a master, and even control a replication slave so that it purposely stays a certain amount of time behind the master. (The latter is very useful for catching errors such as people inadvertently dropping databases - as long as you notice before the slave has caught up, you've potentially saved the pain of having to restore from a complete backup.)

The Maatkit utilities are all written in Perl and they work best on Unix or Linux machines: indeed, Maatkit is now included as a standard part of some Linux distributions. Baron Schwartz is very well known in the MySQL community, and this collection of utilities shows why. It's an invaluable part of any MySQL DBA's toolkit, and I can't recommend it highly enough, especially given that it's absolutely free!

Back In Time for Linux

Mac users will be - or ought to be - familiar with Time Machine, the built-in backup software that comes with OS X version 10.5. The basic idea of Time Machine is that it takes regular incremental backups of your work, adding only changed items to its store. Well, now there's a similar (if rather simpler) program for Linux called Back In Time. Once you've installed it you tell it which directories you want it to back up, and how often it should take snapshots. It will then go ahead and do it and present you with a display of all the files that it's saved for any given snapshot. From there you can select the files you want to restore and choose where they should be copied to.

Since Back In Time takes snapshots so regularly you can restore any earlier version of a file, if a file changes regularly it will have backed up many copies. Deep down, Back In Time is simply a graphical front-end on to the rsync tool, a particularly impressive Linux/Unix tool that's used to compare two directories and copy only what's different between the two. There are none of the cute graphics in Back In Time that you see in Apple's Time Machine, but then many of us are quite happy without such frills and froth. Everyone should have a backup strategy in place and Back In Time is definitely a neat little addition to your arsenal. I've started using it on a Linux machine that I use for testing, and it will make its way onto all the other machines in our office in the very near future.