that the "lightning bloggers" at the MySQL conference achieve total dominance of the "Top 30 Most Active" list on PlanetMySQL. I have so many things going on at the conference that I don't often find time to blog and so my name drops off the active list as fast as you can say "online backup"...

OK, in all seriousness, this post is actually about something... Our friend Julian Cash will be at the conference tomorrow, taking photographs, in his trademark fashion, of conference attendees. His work can be found all over, including Brian Aker's site, and he's been at various open source conferences around the world. He'll be in the …

There’s a reason for Sheeri winning the Community Advocate of the Year award. Her activity level is hard to beat.

If you want a chance to beat Sheeri for 2009, you need to master multitasking. Not only is Sheeri listening to Mårten presenting his keynote. She’s preparing for some vlogging, i.e. recording Mårten’s presentation. And she’s blogging at the same time. And (although she doesn’t know it until three seconds after the picture was taken) she’s getting ready for getting up on stage to receive her 2008 award.

Ah, myself I’m only listening, and taking the odd picture. (Some of them very odd).

In today’s Official MySQL Press Release, PrimeBase XT (PBXT) has been named along with three other storage engine partners in “Sun Celebrates Third-Party MySQL Storage Engines“.

This a great achievement for a small company to be recognized in the certified storage engine partner program, in comparison to the other companies that are much larger on the balance sheet. This continues the news with last week you may have read PrimeBase Technologies a MySQL Platinum Level Partner.

A noted absence from the list is Nitro, an expected absence was Solid.

Today is the first day at the conference (aside from the tutorials, which were yesterday). Here’s what I went to: New Subquery Optimizations in 6.0 By Sergey Petrunia. This was a similar session to one I went to last year. MySQL has a few cases where subqueries are badly optimized, and this session went into the details of how this is being addressed in MySQL 6.0. There are several new optimization techniques for all types of subqueries, such as inside-out subqueries, materialization, and converting to joins.

If you’re at the MySQL Conference and Expo, you can get a free sample chapter of the upcoming High Performance MySQL Second Edition. Just go to the exhibition area. As you go through the doors, take an immediate left and look for the sample chapter on O’Reilly’s table. It’s a rough draft and contains typos and my incredibly crude drawings instead of those that will go into the final book, but it should serve to give you an idea of the book’s depth and scope.

• Suicide
  • having no backups
  • depending on slaves for backup
  • keeping backups on same SAN
  • having a single DBA - Frank didn't like this one at all
  • not keeping binlogs
• Restoring from backup
  • how much time?
  • uncompressed backup ready to mount?
  • separate network for recovery?
• In Fotolog, 1TB of data was severely hit.
  • first problem: backup was highly compressed (tar.gz)
  • uncompressing took hours
  • so keep uncompressed backups (at least last N days)
  • it should be mountable, rather than transferable
• Frank going over recovery modes at …

I'm now at MySQL Conference and have just finished my New Subquery Optimizations in MySQL 6.0 talk. If you're eager to get the slides, here is the link to the pdf file and a mirror.

The talk has the same name as this MySQL University session but the slides have been thoroughly re-worked, and also there is new content:

• More detailed explanation of subquery handling in 4.1/5.x
• More reliable/justified benchmark numbers
• Observations about subquery demographics
• An attempt at comparative analysis of how MySQL's …

Here is the notes from “InnoDB status, architecture and new features” by Heikki Tuuri and Ken Jocobs.

• Introduction
  • Announced Plugin 1.0 for MySQL 5.1
  • fast, reliable, proven
  • fast
    • row-level locking, MVCC -> high concurrency & throughput
    • high performance CPU, memory and I/O architecture
    • efficient indexing (covering)
  • reliable
    • automatic crash recovery
    • integrated referencial integrity and transactions
    • online backup
    • well written, well tested and large user community
  …

I had a chance to visit the Kickfire booth after the keynotes and before the first presentation. They gave me a kicking t-shirt, followed by a presentation on the newly announced Kickfire appliance (now in beta, shipping in Fall 2008). Here are some notes I jotted down:

• von Neumann bottleneck
• SQL chip (SQC), packs the power of 10s of conventional CPUs
• Query parallelization on the chip
• On-chip memory - 64GB. No registers - no von Neumann bottleneck
• Beats the performance of a given 3 server, 32 CPU, 130TB box (1TB of actual data - space is used for distributing IO)
• SQC uses column-store, compression, intelligent indexing
• SQL Chip, PCI connection, plugs into a Linux server
  • SQL execution
  • Memory management
  • Loader acceleration
• KDB (Kickfire storage engine), plugs into MySQL …

Baron Schwartz gave a most interesting talk about EXPLAIN. You will definitely want to read his slides (filled with detail), when they make their way online. These notes are very sparse, just bits that I didn’t see in the slides, that Baron mentioned verbally. Plenty of good questions, and plenty of interaction.

EXPLAIN only works for SELECT queries.

How does MySQL execute queries? Optimisation happens even as the query is being executed. As the query is being optimised, some execution happens as well. Execution Plan is a data structure, not bytecode.

When EXPLAIN’s output is generated, MySQL actually executes the query. It just set’s DESCRIBE on it, rather than executing it. Everything is a JOIN to MySQL (union, SELECT 1 [simplest base case join], etc…).

key_len - to know if your table is indexed well.

rows: estimated number of rows to read, but not the number of rows in the result set. In 5.1 …