At the 2008 MySQL Conference and Expo, The Pythian Group gave away EXPLAIN cheatsheets. They were very nice, printed in full color and laminated to ensure you can spill your coffee* on it and it will survive.

For those not at the conference, or those that want to make more, the file is downloadable as a 136Kb PDF at explain-diagram.pdf

* or tea, for those of us in the civilized world.

Here are two basic tips for proper indexing ...Don't mess with datatypes, too often people refer to an attribute defining it as one datatype in a table and as another in different tables, this actually prevents index usage in joins (forget about FKs for this time ;)) See an example here. You could declare a function based index as a workaround, but why don't we all try to make it right?Put

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Whew! I just finished a marathon of revisions. It's been a while since I posted about our progress, so here's an update for the curious readers.

It's been a while since I've written about progress on the book. I actually stopped working on it as much at the beginning of the month, because on October 31(st) I managed to finish a first draft of the last big chapter! Now I'm back to full-time work at my employer, and I'm working on the book in the evenings and weekends only. Read on for details of what I've been working on and what's next in the pipeline.

I've been trying to circle back and clean up things I left for later in several chapters of High Performance MySQL, second edition. This includes a lot of material in chapter 4, Schema Optimization and Indexing. At some point I'll write more about the process of writing this book, and what we've done well and what we've learned to do better, but for right now I wanted to complete the picture of what material we have on schema, index, and query optimization. The last two chapters I've written about (Query Performance Optimization and Advanced MySQL Features) have generated lots of feed back along the lines …

Your comments on the Advanced MySQL Features chapter were great. A lot of the questions I got (in the comments and via email) about chapter 6 are really addressed in chapter 5, "Query Performance Optimization," so I'm posting its outline too. I have the same questions: are there things you'd like to see us cover? Do you have any favorite techniques you'd like to see us include? Any other comments or questions?

Work continues apace on High Performance MySQL, Second Edition (the link leads to the chapter outline). I'm working now on Chapter 6, Advanced SQL Functionality, and thought I'd solicit input on it. Are there things you'd like to see us cover? Do you have any favorite techniques you'd like to see us include? Feel free to leave feedback in the comments. The chapter is already significantly done, with 26 pages written, but the ink's not on paper yet, so there's still time to correct omissions!

I wanted to point out something that might not be obvious from the name: MySQL Parallel Dump can be used as a generic wrapper to discover tables and databases, and fork off worker processes to do something to them in parallel. That "something" can easily be invoking mysqlcheck -- or any other program. This makes it really easy for you to do multi-threaded whatever-you-need-to-do on MySQL tables. Here's how.

I have run in to the issue where I wanted to change some configuration on our production MySQL server but did not want to restart MySQL since its in production.  One of the parameters we like to change time to time is the “log_slow_queries” so we can see what queries are slow in production environment.  [...] …