The upcoming OpenSQL Camp is almost full! We have space for 130 people to register, and as of this writing only 10 spots are free. If you want to attend, sign up before it’s too late!

We’re still looking for a few sponsors if anyone is interested in helping cover food and t-shirt costs.

I’m organizing the closing keynote panel, “SQL vs NoSQL”, which will include core community members and committers from a number of open source databases. Selena has offered to take the PostgreSQL position if we don’t find another worthy contender. So far, it will include:

• Brian Aker – Drizzle
• Eric Evans – Cassandra
• Joydeep Sen Sarma – Hive/Hadoop
• Mike Dirolf – …

This weekend I attended Drupal Camp PDX and listened to a session titled “Drupal in the Cloud”. The presenter, Josh Koenig from Chapter Three, gave a great introduction of what moving to “the cloud” really means, especially in the context of a typical web application like Drupal. The problem, which is of course no fault of Josh’s, is that the best high availability database practices are harder to deploy because you’re working within a different set of constraints in the cloud. Sure, you can setup MySQL replication, but without the ability to insert a hardware load balancer or better control over floating IPs, reliable single-master solutions are difficult at best.

I spoke with Josh for a bit after and discussed how …

If you’ve ever done any non-blocking programming (usually for socket I/O), you’ve probably had to come up with a non-trivial state machine to handle all the places where everything can pause. Say you’re reading an application level packet from a socket, and half way through the read() system call it screams EAGAIN. You need to stop, save any state, and exit out of whatever chain of functions got you there so the calling application can regain control. I’m going to explain a few techniques I’ve come up with over the years, each with their strengths and weaknesses, and I hope this will spur some conversation of what other folks have done. While I’m fairly happy with how I handle these state machines now, but I’m always looking for a more succinct way of handling things. Please share your thoughts!

Switch Statements

The obvious way to handle non-blocking I/O is with one or more switch statements. Say we need to …

The past week has brought a surge of Gearman related releases. They include:

C Server and Library
Perl Server and Modules
Gearman::XS Perl Module (based on C library)
PHP Extension (based on C library)
PHP Extension Documentation
Drizzle UDFs
PostgreSQL UDFs
MySQL UDFs

Some of …

About a month ago I blogged about the debug console I was adding to drizzled. I finished this work up and it’s now in the trunk and latest release. This is implemented using the Client and Listen plugin points (which are heavily modified versions of MySQL’s Protocol class), and can be enabled using the ‘–console-enable’. For example:

hades> drizzled --datadir=/Users/eday/drizzle.data --console-enable
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use GCC atomic builtins.
090928 15:22:07  InnoDB: highest supported file format is Barracuda.
090928 15:22:07 InnoDB Plugin 1.0.3 started; log sequence number 46409
Listening on :::4427
Listening on 0.0.0.0:4427
./drizzled/drizzled: Forcing close of thread 0  user: '(null)'
./drizzled/drizzled: ready for connections.
Version: '2009.09.1144' Source distribution (trunk)
drizzled> show tables in information_schema; …

Thanks to everyone who came out to the San Francisco PHP and MySQL meetup! Also, thanks to Michael for organizing such a great event, and Percona for sponsoring the food. I put the slides from the talk up on my wiki for reference or in case you missed it. I believe that there will be a video up at some point as well. While down there I also had a chance to stop by Digg and talked to them about Gearman (they’ve been using it for a while). It was interesting to see how they were using it in a large scale deployment. I was able to get some valuable feedback to future development, and a cool t-shirt. :) Thanks Digg!

I’ll be talking about Gearman this Thursday (October 1st, 2009) at the San Francisco PHP and MySQL Meetup groups (these are two separate groups, but sometimes share the topic). A few other folks involved in the Gearman community should also be there to help out, including James Luedke (the PHP extension main author), Eric Lambert (the Java API author), Dormando, and Hachi (Perl version maintainers at SixApart). You can sign up at either the MySQL or PHP meetup groups. We’ll be discussing the basics for those of you who don’t even know what Gearman is, common use cases, new features, advanced topics for folks already using Gearman, and of course Q&A throughout. Hope to see you there! …

Sign up today for OpenSQL Camp 2009! The space is confirmed so go ahead and make your travel arrangements. The event is free and will be taking place in Portland, OR on November 14-15th, 2009. If you are interested in leading a session or presenting a talk, be sure to add it to the session ideas page. Also, we are still looking for sponsors! Please visit the sponsors page if you or your company/organization might be interested. All donations are tax deductible.

We should have representatives from many open source database (and database-related) projects. PostgreSQL, MySQL, Drizzle, memcached, and Gearman, just to name …

Last week on the train to Seattle I was hacking on the new libdrizzle protocol plugin when realized I could really use a debugging console that did not require any socket communication. Since I abstracted a Client plugin in the server (Protocol class for the MySQL folks), this can easily be done by just writing a new plugin. I needed to do some refactoring with the listener plugin to not require a TCP socket/accept and instead poll any arbitrary file descriptor. This allows the the Listen plugin to create the client instance any way it wants. After a bit of hacking and cleanup, we now have this:

shell$ ./drizzled/drizzled --datadir=/home/eday/other/drizzle.data
InnoDB: The InnoDB memory heap is disabled
InnoDB: Mutexes and rw_locks use GCC atomic builtins.
090827  0:29:34  InnoDB: highest supported file format is Barracuda.
090827  0:29:34 InnoDB Plugin 1.0.3 started; log sequence number 8157346
Listening on :::4427
Listening on 0.0.0.0:4427 …

As Brian mentioned, a number of us traveled up to Seattle last week to discuss the road map for Drizzle, Gearman, and memcached. Thanks to everyone who was able to make it! It was great to see folks again (Northscale guys, Robert Hodges, Padraig), and meet a couple new people like Nathan, one of the Google Summer of Code students for Drizzle. I thought I’d take a moment to mention some of the discussions related to the tasks I’m working on.

For Drizzle, we talked about the new configuration and plugin system I’ve been digging into lately. Monty Taylor has been doing a great job refactoring the plugin loading, but there are still some steps to be taken to get things where we want. One of the big goals with all this is to have the plugin and config system not specific to Drizzle at all so we can use this in other projects as well (one being Gearman). There are a bunch …