The latest from the MySQL community

When I received and email almost two years ago about a announcement that MySQL was going to release and enterprise product I was very excited. I was looking forward to a redhat style model of vetting releases in the community then offering a proven stable version to paying customers. I saw it as a great way to for MySQL to generate revenue as well as eliminate the need for people to stay a few releases back from the head and guess when to upgrade.

The release shocked me. What was originally emailed to me and the final plan were two very different things. It was a plan to hand paying customers bleeding edge code that had been tested only by MySQL’s QA team. It seems MySQL has forgotten the years of testing by millions of community members that has given MySQL the stability we have grown to trust. I predicted the instability of MySQL enterprise back in October ‘06 by saying that releasing patches in enterprise that hadn’t been tested by …

We are hitting a few walls with a CouchDB deployment and both Damien and I are a bit puzzled. This posting tries to attract someone with a clue to help us out. Our problems might result from not understanding the documentation correctly, but with evidently inaccurate material, we stand little chance. Here it goes.

Spidermonkey hogs memory

Or its garbage collection is a little ineffective. CouchDB uses Spidermonkey, Mozilla’s Javascript engine to create views on its databases. The user provides a Javascript function and CouchDB uses Spidermonkey to determine which documents to include in a View. The Javascript script that evaluates and executes the user’s function runs as a daemon.

We have a global variable there, map_results (declaration in line 19) that gets reset to {} for each document and map …

I heard someone said that if you do not need to know the intrinsic details of the database, then go for Oracle. I love Oracle because of its robustness. No database can compare against it. It has been there for a long time... Some other database that rose together with Oracle have already died down, but this database still lives.

Am I going to compare MySQL and Oracle here? Nope. For all you know, you really did not have a choice as to which database you have to choose. Your boss chose it for you. So, what is the point of having a title called 'Oracle vs. MySQL' if I'm not going to compare them? Nothing really. It's just a point where there are certain things in life that you really don't have control about.

If you enable logging of all queries as "slow queries" using the patch or MySQL 5.1 you can get log file to grow huge. Same may happen with general log file. In some cases we've got log file sizes of 100G or more which may need to be cleaned up.

Here is some danger waiting for you at least on typical Linux systems - If you follow most simple process - delete log file you do not need and run "FLUSH LOGS" so file is recreated and space reclaimed you can get into serious trouble. File close operation will when perform deletion which can be quite a long process, depending on filesystem and log file size - we've seen it to take 10 minutes or more in some cases. When log file is reopened MySQL will be practically unavailable causing unanticipated downtime.

The workaround for this problem is very simple - instead of deleting …

The review of my first six months of service with (mt) Media Temple is posted at Web Hosting Talk.

I was looking for a function in the MySQL documentation on how to get the first day of the month and I couldn't find one. Although I found that there was a LAST_DAY function. So, here's my function to get the first day of the month.

select DATE_ADD(LAST_DAY(DATE_SUB(CURDATE(), interval 30 day), interval 1 day);

This is how I computed the first day of the month. I'm not sure if there is a simpler way of doing this.

If you are migrating your production environment to MySQL database or even thinking about it, you do not want to miss this webinar Experts from Zmanda and MySQL will present various methods to backup MySQL database and correlate them with tools and terminology you may be familiar with in other databases, including Oracle.

A good pre-read for this webinar would be Paddy’s blog on online MySQL Backup

WHO:

Chander Kant, CEO, Zmanda

Robin Schumacher, Director Product Management, MySQL

WHAT:

MySQL Backup Techniques for the Oracle DBA (web presentation)

WHEN:

Thursday, December 13, 2007, 10:00 am PDT, 1:00 pm EDT, 18:00 GMT
The presentation will be approximately 45 minutes long followed by Q&A.

What do you do when your database is falling behind?

1. Optimize the queries that are running on your database.
2. Try to partition your data so extensive I/O database will be distributed evenly.

If both approach don't work, you have one option left and that is to migrate your database to a new hardware. Here are pointers on what you have to do.

1. Backup your previous data.
2. Make sure that the new hardware configuration is identical with the old hardware.
3. Prepare for a downtime meaning you have to shutdown your database.
4. Copy your data to the new hardware.
5. Test your data in the new hardware.

Sheeri wrote a post (now a 404 error) referring to Maatkit on Ohloh, which I have never heard of before. I took a look at what Ohloh thinks about Maatkit. It's kind of neat. Beyond just the obvious "social website" stuff that's all the rage these days, it actually looks at the project's SVN history, analyzes the codebase, and so on.

It also estimates 8 person-years of work have gone into the project, and says that at $55,000/year it would cost $450,702 to write the code as it currently exists, which is kind of funny. It took me a whole lot less than 8 years to write. (Perhaps this is why that salary strikes me as unrealistic).

It has a couple of other interesting things, like a visual timeline of source …