MySQL
I’m looking forward to traveling to San Jose for this year’s MySQL Conference. If there’s anything that can trump the drama of conf two years ago, where we observed how Sun would handle its new property, and then the drama of last year, where we observed how Oracle would handle the pending acquisition, it’s going to be the drama around this one — the first MySQLConf since the Oracle/Sun merger has been finalized and approved.
I’m excited to share the news that Oracle ACE program has been extended to cover MySQL community now and Pythian’s Sheeri Cabral has become the very first Oracle ACE Director in MySQL expertize area. It’s a special privilege for me to blog about it because I had a pleasure to nominate Sheeri in the first place. Being an Oracle ACE Director myself and knowing what’s involved, I believed that if Oracle ACE program is extended to MySQL, Sheeri must be the number one candidate.
Here’s what Pythian is cooking up for MySQL Conference this year.
If I told you that your database had a ratio of temporary tables written to disk of 20%, you might think “aha, my database is slow because of a lot of file I/O caused by writing temporary tables to disk!”. However, that 20% ratio may actually mean a rate of 2 per hour — which is most likely not causing excessive I/O. To get a sense of this concept, and also how mysqltuner works, I will show the lines from the mysqltuner default configuration that deal with temporary tables written to disk.
I recently granted ALTER access in MySQL so a user could run the ALTER TABLE command . However after I granted the necessary privileges, the user was still not able to perform the tasks needed. Then I realized what the issue was and how to fix it.
There are those that are very adamant about letting people know that using INFORMATION_SCHEMA can crash your database. Of course they leave out one extremely important piece of information: you can actually figure out how dangerous your INFORMATION_SCHEMA query will be, ahead of time, using EXPLAIN. Here’s how.
Last month at the Boston MySQL User Group, I went through the meanings of INNER, LEFT/RIGHT OUTER, CROSS, NATURAL joins, how to do a FULL OUTER JOIN in MySQL, and what STRAIGHT_JOIN means. I also explained how to recognize when you want those types of joins, and best practices for the semantics of writing joins and design patterns. Subqueries were explained in this session, and some examples of how to think differently so that you end up writing JOINs instead of subqueries. The slides and video are posted here.
The call for proposals for Birds of a feather sessions closes at 11:59 pm PST on Thursday, February 18th, 2010. Sessions can be added during the conference, but if you submit and your BoF is accepted it will be printed in the schedule.
In light of the official Oracle acquisition of Sun, I dug out a presentation video I realize I never officially shared with either the MySQL or the Oracle community. It’s the presentation I did at the 2008 Oracle Open World conference called, “So, you want to be an Oracle ACE?” and is a good resource for anyone who wants to contribute to anything — not just Oracle or MySQL, though certainly it’s based on my experiences with contributing to MySQL. Have a look.
On first glance, it looks like TEXT and VARCHAR can store the same information. However, there are fundamental differences between the way TEXT fields and VARCHAR fields work, which are important to take into consideration. I explain them in detail.
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