I am still a MySQL/Sun/Oracle employee, but the process made me realize I should just dust off my own domain and, um, be master of it. 

Future entries will be at http://www.worldgonemad.com/blogs/

Anybody else wanting a blog site is happy to use mine as well.  

Thanks!

When I started looking into managing hierarchical data I found a lot of short articles that provided bits and pieces of the big picture, but nothing gave a good in-depth review of everything I needed to know to handle hierarchies.

One trend that began to develop was that the best information on the subject was coming from Joe Celko, a rather prolific author/speaker on all things SQL.

Joe Celko has a book in publication called SQL For Smarties, and this book had some basic information on handling hierarchies, which he followed up with Trees and Hierarchies in SQL for Smarties, a truly excellent book on the subject.

This book is not for the faint of heart, but it really is a must-read for those who are looking to handle hierarchies in SQL.

The book only addresses MySQL once, and while in that section it repeats Joe's opinion of MySQL not being a real database, users of MySQL 5 can rest assured that the stored …

This is the 176th edition of Log Buffer, the weekly review of database blogs.

There were heaps of mostly technical posts this week. I think bloggers are tired of kicking around the ins-and-outs of Sun and Oracle, and wanted to talk about what really matters. So let’s start with . . .

Oracle

Harald van Breederode shows how to setup a private DNS for your virtual cluster.

Pythian’s Alex Fatkulin discusses Oracle GoldenGate …

At the Oracle-Sun merger coming-out party, Larry Ellison asked “what is cloud computing?” suggesting it is the same old stuff of hardware, software and the Internet. Let me try to answer this question from various perspectives.

Cloud computing is an umbrella term that describes:
• Provisioning of compute services;
• Billing of the compute services

Provisioning of Compute Services:
Compute services are provisioned from a pool of hardware/networking/power. In other words you don’t buy or lease individual hardware and accoutrements; you simply use what you need from a pool of such resources.

The above describes the hardware layer; the software layer can also be shared or sandboxed. For example, Google offers a shared software layer, they provide the file system, key-value store, operating system, etc. Each of these are designed for multi-tenancy and all users run on this same …

Somebody asked in Freenode the other day how to get their data out of MySQL into a specific XML format.

Both mysqldump and the mysql client have --xml options. The output from the cli looks like this:

<resultset statement="SELECT here">
  <row>
    <field name="field1">value</field>
    <field name="field2">value</field>
  </row>
  <row>
    <field name="field1">value</field>
    <field name="field2">value</field>
  </row>
</resultset>

I wanted to change those <field name="fieldName"> into <fieldName> tags, and all it takes is a little XSLT, which I've uploaded …

According to a recent post from the Google Blog, Unicode nearing 50% uptake on the web. A rather steep graph as well:

This is pretty good news. I've had the 'pleasure' of working with a number of integration project where the 3rd party was still using iso-8859-1 (aka latin-1). Usually when this is the case, its not by choice but because of their software's default settings (Browsers, MySQL, etc.). I for one hope non-unicode charsets will soon be a thing of the past.

One other note in the post was about ligatures, such as fi and the dutch ij. If this is the first time you heard about these, you might be surprised to see that you can (likely) …

How To Back Up MySQL Databases With mylvmbackup On Debian Lenny

mylvmbackup is a Perl script for quickly creating MySQL backups. It uses LVM's snapshot feature to do so. To perform a backup, mylvmbackup obtains a read lock on all tables and flushes all server caches to disk, creates a snapshot of the volume containing the MySQL data directory, and unlocks the tables again. This article shows how to use it on a Debian Lenny server.

LinuxTag is the most important place for Linux and open source software in Europe. Last year, LinuxTag had over ten thousand attendees, and over 300 speakers. This year, the 16th LinuxTag will be June 9-12, 2010 at the Berlin Fairgrounds in Germany.

LinuxTag seeks exciting and suitable proposals for presentations in the conference tracks. The Call for Papers ends today.

I am proud to be a member of the LinuxTag Program Committee. Although a lot of proposals have already been submitted, there are some topics missing that I’d personally like to see covered. So, if you’re up for a last minute submission, get your inspiration from the following list:

• Is/was the recent economic crisis an …

If there is one thing that confuses people about tables in MySQL Cluster (including me at times) it is BLOB/TEXT columns.  When NDB was originally created it was not designed to handle BLOB data, so the handling of BLOB data was difficult to implement and is sometimes not exactly what users expect.

How MySQL Cluster BLOBs work

When you create a table in MySQL Cluster which has a BLOB column the first 256 bytes of the BLOB is stored in the main table (and in memory when using disk data tables), subsequent data is then stored in a hidden table (typically split into 2KB rows).  This means there is an extra table for every BLOB or TEXT column in your main table (and extra resource usage).

BLOB locking in MySQL Cluster

These extra tables can cause some problems, firstly with performance (retrieving BLOB data is not very fast) and more importantly with locking.  MySQL Cluster works in …

At DrupalSouth 2010 (Wellington) after LCA2010, Peter and I implemented a Drupal module as a practical example of how the OQGRAPH engine can be used to enable social networking trickery in any website. The friendlist_graph module (available from GitHub) extends friendlist, which implements basic functionality of friends (2-way) and fans (1-way) for Drupal users.

The friendlist_graph module transposes the friendlist data using an OQGRAPH table, allowing you to query it in new and interesting ways. By adding some extra Drupal Views, it allows you to play Six …