I caught most of the second day of MySQL Camp 2007. It was fun and educational as before. The format was a little different than the last Camp; everything was in one room. Google and Proven Scaling provided food.

Sessions were loosely organized, to say the least, but that’s what an un-conference is [...]

I've just released changes to all tools in MySQL Toolkit. The biggest changes are in MySQL Table Sync, which I'm beginning to give sane defaults and options to. Some of the changes are incompatible (but that's what you get with MySQL Table Sync, which is still very rough). I also found and fixed some bugs with MySQL Visual Explain. Thanks to everyone who submitted bug reports.

Note, the formatting overflow in MySQL Query Profiler was not a security vulnerability. It was simply an issue with a Perl formatting code that displayed numbers as hash marks when they got big enough.

I'm attending the Google Test Automation Conference (GTAC 2007) in Manhattan, New York right now. It's a two-day single-track event hosted by Google, with mostly non-Google speakers. It's okay, but not great.

There is no "first" or "last" aggregate function in SQL. Sometimes you can use MIN() or MAX(), but often that won't work either. There are a couple of ways to solve this vexing non-relational problem.

First, let's be clear: I am posing a very non-relational problem. This is not about the minimum, maximum, top, most, least or any other relationally valid extreme in the group. It's the first or last, in whatever order the rows happen to come. And we all know rows aren't ordered -- in theory. But in practice they are, and sometimes you need the first or last row in a group. This article shows how.

MySQL AB's recent changes to the Community/Enterprise split have made people go as far as calling the split a failure. I don't think it's working well either, but it could be fixed. Here's what I think would make Enterprise a compelling offer.

MySQL Slave Delay implements an oft-requested replication feature: the ability to make a slave lag its master, a.k.a scheduling binlog events for some time in the future. This will probably be built into MySQL replication someday, but in the meantime, you can use this tool. A delayed slave is great if disaster strikes and propagates through replication, because it lets you stop the delayed slave before it gets corrupted, restart the slave until just before the offending statement, and recover quickly. This is a lot faster than restoring last night's full backup and replaying a day's worth of binary logs on the master.

Is MySQL giving you the error message "ERROR 1200 (HY000): The server is not configured as slave; fix in config file or with CHANGE MASTER TO" when you try to run START SLAVE? There are a few simple troubleshooting steps to take, but I always forget what to do. This article is to help me remember in the future!

If you've ever wished you could see MySQL's EXPLAIN output formatted as a tree, now you can. MySQL Visual Explain transforms EXPLAIN output into a hierarchical view of the query plan, which is significantly easier to read and understand.

Is your MySQL server doing an extra index scan on queries that need to check a key for matches or NULL? It's easy for this to happen accidentally, but it's also easy to fix, especially in MySQL 5.0 and up. Here's how.

I've just released changes to two of the tools in MySQL Toolkit. MySQL Table Checksum got some convenient functionality to help you recursively check slaves for bad replicated checksum chunks. MySQL Archiver got statistics-gathering functionality to help you optimize your archiving and purging jobs, plus a few important bug fixes.