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 (slightly different from the slides in the video — due to error correction) can be found at http://technocation.org/files/doc/2010_01MySQLJoins.pdf.

Here’s the video:

The Call for Proposals for the 2010 MySQL User Conference and Expo ended about 6 hours ago. However, birds-of-a-feather sessions (BoFs) have a separate call for proposals. From the MySQL Conference page at http://en.oreilly.com/mysql2010/, select the “Program” menu item, then “Birds of a feather sessions”, and you will be directed to the proper page. Which, for easy clicking, is http://en.oreilly.com/mysql2010/public/cfp/90.

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.

Note: If you submitted a BoF proposal in the regular call for proposals, it’s much much easier if you submit the proposal again …

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.

Oracle has lots of resources for the community. While I have joked about Oracle calling its conference “Open World”, I have also experience it, and the Oracle community first-hand and second-hand — through professional contacts such as my colleagues at Pythian who work on Oracle databases, and also through personal contacts such as my mother who has been to a few Oracle conferences herself.

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Ronald Bradford’s recent warning to be sure to know your my.cnf sections reminded me of a similar issue that I ran into last summer, where putting the “group” option in both the [mysqld_safe] and [mysqld] directives resulted in a mostly silent problem.

I started noticing this in MySQL 5.1 and it affected both the official MySQL binary and the Percona binary. In trying to be conscientious, I had the following set:

[mysqld_safe]
user=mysql
group=mysql

[mysqld]
user=mysql
group=mysql


However, when the MySQL server started up, the error log showed

[Warning] option 'group_concat_max_len': unsigned value 0 adjusted to 4

This was obviously a problem, but …

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.

Standard
VARCHAR is actually part of the ISO SQL:2003 standard; The TEXT data types, including TINYTEXT, are non-standard.

Storage
TEXT data types are stored as separate objects from the tables and result sets that contain them. This storage is transparent — there is no difference in how a query involving a TEXT field is written versus one involving a VARCHAR field. Since TEXT is not stored as part of a row, retrieval of TEXT fields requires extra [edited 1/22] memory overhead.

Maximum VARCHAR length
The maximum row length of a VARCHAR is restricted by the maximum row length of a table. This is 65,535 bytes …

We’re looking for an intermediate to expert MySQL DBA who can jump right in. We have several offices in Ottawa, Boston, Sydney and Hyderabad, India.

Working at Pythian is different than working in-house or as a consultant, because you’ll be making your contributions available to each of the customers assigned to your team, allowing you to see more use cases, more technologies, and work with more and varied environments, all the while building interesting and long-lasting working relationships with your peers. I will gladly sponsor a work visa for the right candidate anywhere in the world.

We support some of the most interesting internet-scale MySQL environments in the world, see http://www.pythian.com/about/customers/ for a sampling of customers across many industries.

Top Criteria

* Outstanding MySQL production administration …

The O’Reilly MySQL Conference & Expo 2010 Call for Participation ends in just under 3 weeks. I am on the conference committee, and thus get to see and review all the conference proposals.

This blog post will briefly explain the how each part of the proposal is used, then have a list of what not to do in your conference proposal, and end with a checklist of questions to go over your proposal before submitting. Click here if you want to skip to the checklist.

The proposal has several parts.
Title: This is the title of your presentation. This shows up on the schedules …

In this article I am responding to many parts of Monty’s post at http://monty-says.blogspot.com/2009/12/help-keep-internet-free.html which are just plain not true, or are exaggerations.

I will give my own answers to the self-interview questions Monty provides, as I feel he is using his name and popularity to spreading fear that is not warranted.

Q: Why don’t you trust that Oracle would be a good owner of MySQL?

I cannot say whether or not Oracle would kill MySQL. However, I have already stated I believe Oracle will not kill MySQL. This is based on the fact that Oracle has had the chance to kill MySQL for several years, by making InnoDB proprietary, and has not.

Folks can debate …

OpenSQLCamp was a huge success! I took videos of most of the sessions (we only had 3 video cameras, and 4 rooms, and 2 sessions were not recorded). Unfortunately, I was busy doing administrative stuff for opensqlcamp for the opening keynote and first 15 minutes of the session organizing, and when I got to the planning board, it was already full….so I was not able to give a session.

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• Comparing Non-Relational Databases: MongoDB, Tokyo Tyrant, CouchDB by Igal Koshevoy of Pragmaticraft

Another video from the recent OpenSQLCamp in Portland, Oregon….Earlier today I uploaded the Lightning Talk Videos. Due to the holiday I am unsure when the rest of the videos will be ready. When they are, I will do one blog post featuring them all.

However, I have had several requests for this specific video, so here is Brian Aker speaking about Drizzle.

The slides are up at http://www.slideshare.net/brianaker/drizzle-opensql-camp, and here’s the video:

(Note, I will not do a post for each video…..but since this one is up and ready, I figured I’d do it before I leave for the holiday).