MySQL Cluster is well known as an in-memory database which can be restrictive (a server typically has a RAM limit) so it may surprise some to learn that you can also store MySQL Cluster data on disk.  Disk Data Tables have been in MySQL Cluster for quite a while, the first GA release with them included was 6.2.  They do have caveats which I will describe here, many of which already have plans to be improved in future versions.
How Disk Data Tables work

A set of UNDO logs and data files can be created which are on every data node in the cluster.  The UNDO logs bring the disk data back to a consistent point so that during node restart the REDO logs can be replayed when a node is started.

Not all data in a disk table is actually stored on disk, the main two things that are not are indexed columns (the entire column is in main memory, not just the index) and the first 256 bytes of a …

The mobile world is changing. It's changing faster than the database world did back when MySQL was started and grew to be one of the most widely used database in the world.

Change brings turbulence and it's difficult trying to see the big picture to find the major trends. It also means different philosophies of doing things clash and fight for survival.

There are two large debates at the moment around mobile. One is about open versus closed platforms and the other is around native applications versus web based. One of them is an important philosophical issue, the other one a more technical question of the best way to bring a good user experience to mobile.

The success of the iPhone and the App Store has meant a huge leap for both mobile applications and mobile web. But the iPhone platform is closed. The entire ecosystem is controlled by one company.

On the Internet it's (somewhat) safe to …

I'm pleased to announce the release of Spider storage engine version 2.13(beta).
Spider is a Storage Engine for database sharding.
http://spiderformysql.com/

The main changes in this version are following.
This release is bug fix release.

Please see "99_change_logs.txt" in the download documents for more detail.
Thanks to Mitsuhiro for bug report.

Enjoy!

I am currently working as a Database Administrator with Linux Systems Administrative components for REA-Group. The company specialises in online advertising in the property space - with websites like realestate.com.au and casa.it and my role is the optimistion, up-time and performance of the underlining database infrastructure. Prior to REA, I was working as a Database Administrator for Rackspace Hosting in their managed hosting team, one of the biggest hosting companies in the world.

I specialise in MySQL Server performance as well as in performance of the LAMP stack. realestate.com.au is a 600 webpage hit-per-second website and challenges around performance, redundancy and optimisation is what I love the most.

You can find me on linked in at: …

At my current job, I have seen much over indexing in some of our production schemas.

Here is a quick rule of thumb; if you have an schema such as
CREATE TABLE blah ( col1 int default not null, col2 int default not null, primary key (col1,col2), key col1, key col2);
or
CREATE TABLE blah ( col1 int default not null, col2 int default not null,unique key (col1,col2), key col1, keycol2);


The index ‘key col1’ is redundant to the primary (or unique key) as col1 is the first in the other indexes tuple. Creating the col1 index will do nothing more than cause a big performance hit for updates and reduce the valuable useful space of the innodb buffer pool (if innodb is being used) intern making things slow.

I’m speaking at the O’Reilly MySQL Conference 2010. I hope I don’t lose my voice, because I have four sessions!

• Diagnosing and Fixing MySQL Performance Problems
• EXPLAIN Demystified
• Read-Write Splitting: Techniques, Challenges, and Solutions
• MySQL Graphing and Trending with Cacti

You can click through on the links above to learn …

I’ll be attending PgEast this year, as I’ve done for the last couple of years, and this year I’ll also be speaking. The topic is query analysis with mk-query-digest. The official description of my talk is as follows:

mk-query-digest is a powerful open-source tool for capturing, filtering, transforming, and aggregating queries, with the ability to do all sorts of other advanced tasks too. By default, it aggregates similar queries together and presents a designed-for-DBAs report with statistics about the most important queries, so you can see where to focus your optimization efforts. This talk shows you how to use mk-query-digest to analyze your Postgres server’s workload.

…

Maatkit does more than just MySQL. I’ve just committed a new version of mk-query-digest, a powerful log analysis tool, with support for Posgtres logs, in both syslog and stderr format. I’m hoping that people will give this a spin in the real world. I have lots of test cases, but that’s never enough; I’m looking for people to crunch their logs and let me know if anything breaks.

A brief tutorial:

# Get it
$ wget http://www.maatkit.org/trunk/mk-query-digest

# Run it
$ perl mk-query-digest --type pglog /path/to/log/file

# Learn about it (search for the string "pglog")
$ perldoc mk-query-digest

I’m going to close comments on this blog post so I don’t get bug reports in the comments. If you have feedback, please post it to the Maatkit mailing list, or …

I’m speaking at the O’Reilly MySQL Conference 2010. I hope I don’t lose my voice, because I have four sessions! Diagnosing and Fixing MySQL Performance Problems EXPLAIN Demystified Read-Write Splitting: Techniques, Challenges, and Solutions MySQL Graphing and Trending with Cacti You can click through on the links above to learn more about each session. I’m also looking forward to the other sessions. Here’s a sample of a few that I have my eye on:

Maatkit does more than just MySQL. I’ve just committed a new version of mk-query-digest, a powerful log analysis tool, with support for Posgtres logs, in both syslog and stderr format. I’m hoping that people will give this a spin in the real world. I have lots of test cases, but that’s never enough; I’m looking for people to crunch their logs and let me know if anything breaks. A brief tutorial: