It's been said before, but good judgement comes with experience, but experience comes from bad judgement We all know the golden rules on database backups: 1. do backups 2. test that you can restore from those backups But how many of us actually do that second part? I've recently gained some experience (ahem!) on the importance of step 2.

I'm spending quite a lot of time at the moment working on performance optimisations for Analytics SEO, and learning much more about the subtle differences between the different MySQL storage engines.

We've been seeing a lot of contention on one of the larger tables in our database recently. This table has a few billion rows (around 300GB), and uses MyISAM. As our usage has increased, we've started seeing more SELECTs being blocked by UPDATEs, so decided to switch the table to use InnoDB to allow concurrent reads and writes.