Tool to generate large datasets of test data Many times when trying to come up with an efficient database design the best course of action is to build two sample databases, fill them with data, and run some queries against them to see which one performs better.

Is there a tool that will generate (ideally straight into the database) large (~10,000 records) sets of test data relatively quickly?  I'm looking for something that at least works with MySQL.
The best tool (if you can find it) is DataFactory. (Sadly out of print). I've generated absolutely delightful (and quite authentic-looking) datasets from it.

Generatedata.com is... acceptable, but doesn't scale very well.

DataGenerator is something to keep an eye on.

And while DTM Data Generator is clunky and a poor substitute for DataFactory, it exists and is being sold, and I've used it to generate mildly acceptable data.