MySQL by default is a NON transactional database. For the hobbyist (See The Hobbyist and the Professional), startup entrepreneur and website developer this may not appear foreign, however to the seasoned Oracle DBA who has only used Oracle the concept is very foreign.

In MySQL you have to be concerned with two situations that will catch the unprepared out. The first is the default autocommit mode. This is TRUE, i.e. all statements are automatically committed on completion.

mysql> SELECT @@autocommit,TRUE;
+--------------+------+
| @@autocommit | TRUE |
+--------------+------+
|            1 |    1 |
+--------------+------+
1 row in set (0.00 sec)

The second is the storage engine used. Again a foreign term for Oracle DBA’s, a storage engine is a technology that stores and retrieves the underlying data from the …

This month will see the release of the book Expert PHP and MySQL which I was a co-author of. Initially this will be available for purchase in PDF format from the Wrox website and I am hopeful this will be available in print format for the MySQL Users Conference.

More then just your standard PHP and MySQL there is detailed content on technologies including Memcached, Sphinx, Gearman, MySQL UDFs and PHP extensions. We will be posting more information at www.ExpertPhpandMySQL.com. You can download a PDF version of Chapter 1 Techniques Every Expert Programmer Needs to Know.

The book includes the following content:

I’ve heard about the innodb_plugin but not had time to put it to the test.

Recently though due to some problems I’ve been having with the MySQL Enterprise Monitor (Merlin) I’ve had to try a few changes and had the opportunity to try out the innodb plugin.

I have been using Merlin for some time and like it a lot. It is not perfect but does a good job for me.  However, since upgrading to version 2.1 I have been having some database load problems. I long ago split the merlin server into a front- and back-end server with the backend running a standard MySQL 5.1 Advanced package. That has been working fine.

I have been monitoring more and more mysqld servers and recently the database backend could not cope. Basically the writes of …

In Oracle the default transaction isolation is READ_COMMITTED. In MySQL the default is REPEATABLE_READ. Because MySQL also has READ_COMMITTED I have seen in more then one production MySQL environment a transaction isolation of READ_COMMITTED. The explanation and ultimately incorrect assumption is the default in Oracle is READ_COMMITTED so we made that the default in MySQL.

I’m not going to discuss the specific differences of these isolation levels (see reference lines below) except to say it that READ_COMMITTED in Oracle more closely relates to the MySQL default of REPEATABLE_READ and not READ_COMMITTED. Just because the same term for a common feature exists, don’t assume the underlying functionality is the same or that either or both actually conform to the SQL ANSI standard.

While switching your MySQL environment to READ_COMMITTED is possible, there is still conjucture if this actually provides any performance improvement. …

MySQL system variables and status variables have two scopes. These are GLOBAL and SESSION which are self explanatory.
This is important to realize when altering system variables dynamically. The following example does not produce the expected results.

mysql> USE test;
Database changed
mysql> CREATE TABLE example1(
    -> id INT UNSIGNED NOT NULL AUTO_INCREMENT,
    -> col1 VARCHAR(10) NOT NULL,
    -> PRIMARY KEY(id)
    -> );
Query OK, 0 rows affected (0.29 sec)

mysql> SHOW CREATE TABLE example1\G
*************************** 1. row ***************************
       Table: example1
Create Table: CREATE TABLE `example1` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `col1` varchar(10) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=MyISAM DEFAULT CHARSET=latin1
1 row in set (0.00 sec)

We see that the table has a default CHARACTER SET of latin1. If you wanted to ensure all tables are …

As part of my MySQLCamp for the Oracle DBA series of talks to help the Oracle DBA understand, use and appreciate MySQL I have also developed a series of short interesting posts I have termed “Don’t Assume”. Many of these are re-occurring points during my consulting experiences as I observe Oracle DBA’s using MySQL. I am putting the finishing touches to my MySQL for the Oracle DBA series of talks and I’m excited to highlight some of the subtle differences and unique characteristics of MySQL RDBMS in comparison to Oracle and some extent other products including SQL Server.

Stay tuned for more soon.

I will be presenting at the MySQL Users Conference 2010 in Santa Clara, April 2010 two presentations from this series, …

This Thursday (March 4th, 15:00 UTC - slightly later than usual), Robin Schumacher will present MySQL Column Databases. If you're doing Data Warehouse with your databases this is a must-attend, but it's also interesting to learn what typical other scenarios there are for using column-based storage engines, and how column databases work in the first place.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. You may register for a Dimdim account, but you don't have to. (Dimdim is the conferencing system we're using for MySQL University sessions. It provides integrated voice streaming, chat, whiteboard, session recording, …

This Thursday (March 4th, 15:00 UTC - slightly later than usual), Robin Schumacher will present MySQL Column Databases. If you're doing Data Warehouse with your databases this is a must-attend, but it's also interesting to learn what typical other scenarios there are for using column-based storage engines, and how column databases work in the first place.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. You may register for a Dimdim account, but you don't have to. (Dimdim is the conferencing system we're using for MySQL University sessions. It provides integrated voice streaming, chat, whiteboard, session recording, …

This Thursday (March 4th, 15:00 UTC - slightly later than usual), Robin Schumacher will present MySQL Column Databases. If you're doing Data Warehouse with your databases this is a must-attend, but it's also interesting to learn what typical other scenarios there are for using column-based storage engines, and how column databases work in the first place.

For MySQL University sessions, point your browser to this page. You need a browser with a working Flash plugin. You may register for a Dimdim account, but you don't have to. (Dimdim is the conferencing system we're using for MySQL University sessions. It provides integrated voice streaming, chat, whiteboard, session recording, …

As a part of Global Ignite Week I will be doing an updated "Guide to NoSQL". Ignite Seattle will be taking place at the King Theater in Bell Town next Thursday, March 4th.

I'm hoping for better audio this time :)