You can hack the MySQL server in three ways:

• Changing the server code. This is straightforward. Download the code, and make the changes you need. If you need the change only for a limited period, this is enough. If the change must be persistent, then you should try to make it accepted. The Code Contribution Program may be for you.
• Creating a plugin or a UDF. Using the plugin interface or the UDF API you can extend the server in many ways. UDFs require that you (and the user) be able to compile the additional code. Plugins require compiling code only from the author.
• Mixing the existing hooks. This means being creative bu stretching the intended …

(See this post for background information on MySQL Function of the Day)

Week Two:

• Wednesday, March 12, 2008: ELT()
• Thursday, March 13, 2008: IF()
• Friday, March 14, 2008: REPEAT()
• Monday, March 17, 2008: FLOOR()
• Tuesday, March 18, 2008: DIV()

Week One:

• Wednesday, March 5th, 2008: CHAR_LENGTH()
• Thursday, March 6th, …

If you're serious about MySQL, it doesn't hurt to know the people closely tied to its development and maintenance as well as famous bloggers. Here's my ongoing list of people I consider important:

Peter Zaitsev - MySQL Performance Blog, former head of MySQL AB High Performance Group. His company Percona is available for consulting. He's a co-author of High Performance MySQL 2nd edition (great book).

Baron Schwartz - also know as Xaprb, Baron a co-author of High Performance MySQL 2nd edition and creator of …

I can't say that I look forward to any …

Just as a head’s up to students that are thinking about participating in the Google Summer of Code 2008, and were planning on being affiliated with MySQL. You can - MySQL has just been accepted into the Summer of Code 2008.

We have an ideas page (watch it closely, there will be many changes in the coming weeks), we also have a mailing list (subscribe to it, and discuss with potential mentors), and now, all we want are plenty of students!

This should also be a note, that its a call for mentors. Last year, we had Paul McCullagh and Sheeri Kritzer Cabral, mentor projects from outside MySQL, and it was great. Participation from the …

I posted a simple INFORMATION_SCHEMA query to find largest tables last month and it got a good response. Today I needed little modifications to that query to look into few more aspects of data sizes so here it goes:

Find total number of tables, rows, total data in index size for given MySQL Instance

PLAIN TEXT SQL:

1. mysql> SELECT count(*) TABLES,
2.     ->        concat(round(sum(table_rows)/1000000,2),'M') rows,
3.     ->        concat(round(sum(data_length)/(1024*1024*1024),2),'G') DATA,
4.     ->    concat(round(sum(index_length)/(1024*1024*1024),2),'G') idx,
5.     ->    …

In the past few months I’ve not had to look for a job, they look for me. If your a well qualified MySQL DBA there are many opportunities, I’ve had so many of these offers in the past 12 months I’ve lost count. However a DBA job would not offer the job satisfaction I’m seeking in my career goals now in 2008.

I’ve been able to consider 4 genuine positions in just the past few weeks, and indeed my new employer Primebase Technologies was someone I’d never considered working for, and indeed they had never considered me until a chance lunch meeting less then one month ago.

I did seriously consider working with Paul Vallee and the team at Pythian. Pythian looks for the best people from their respective levels of technology expertise, whether a college graduate or a 2 decade RDBMS veteran. This company has a great work …

Tim Bunce, the author of the Perl DBI, the database library that has influenced similar works in most languages, has published a presentation about Perl myths. The essential list of myths goes:

• Perl is dead. No, it's alive and kicking (look at the numbers)
• Perl is difficult to read. So are Java and C++, when written by bad programmers.
• Perl 6 is killing Perl 5. Actually, the opposite is true. While Perl 6 is taking way too long to be implemented, its analysis has advantaged Perl 5, which has grown new features and performance in 5.10.

Highly educational stuff, as it is this other article: Good Perl code is the best form of evangelism.
As for me, Perl is my main tool of the trade, not only with …

Sun Microsystems, Inc. and Zmanda, the open source leader in backup and recovery software, today announced they are partnering to deliver a comprehensive, global data backup and recovery solution for MySQL Enterprise subscribers. A 30-day trial of Zmanda Recovery Manager Enterprise Edition -- the first open-source backup and recovery solution designed specifically for MySQL™ databases -- is available now at www.mysql.com/zrm. Starting April 1, MySQL Enterprise customers will be able to purchase ZRM for MySQL directly from Sun worldwide. Zmanda and Sun have also agreed to joint-selling and co-marketing activities in support of MySQL, the world's most popular open source database software.

Typically, when choosing a composite index structure, your favorite DBA will tell you to put the most selective columns first. Now, when I tell people that I tend to get a few blank stares, so first, what does selective really mean?

It means, that for the given set of columns, the columns with the more UNIQUE values are more selective than columns with less UNIQUE values. In general, putting more selective values before less selective values in a composite index will result in faster access. This assumes however that comparison operations involve the EQUALS (=) operator.

To demonstrate selectivity:

Table
Col1  Col2
1     1
2     1
3     1

Query
select * from Table where Col1 = 1 and Col2 = 1

In this first example `Col1` is more selective than `Col2`. Think of selectivity as the number of rows that need to be read to make a comparison against a single …