I’ve just finished watching a presentation that Jonathan Lewis has recorded and made available which covers how the optimizer works and how you have to think when dealing with a difficult problem in SQL.
The presentation is (as you’d expect) extremely well done and Jonathan covers some extremely advanced subjects in a way that makes them (slightly!) easier to understand. I attended one of the presentations that Jonathan did at Open World and I can remember sitting there thinking “That makes sense, I must look into doing that” and then of course once you get back home other things crop up and you don’t get a chance to look at it again.
I’m very happy that Jonathan has chosen to share the presentation online, it makes fascinating watching and I have learned a huge number of useful things.
So, do yourself a favour, grab a coffee/tea/beverage of your choice, take the phone off the hook, put up a Do-Not-Disturb sign on the door and watch the presentation, your experience with the database will be all the better for it.