Ironically, the Stream algorithm I wrote as the simplest possible syncing algorithm does what the much more efficient algorithm I wrote some time ago can't do: sync a table without a primary key, as long as there are no duplicate rows. In fact, it's so dumb, it will happily sync any table, even if there are no indexes.

The flash of inspiration I had on Friday has turned out to be good...

To illustrate how easy and straightforward writing applications for CouchDB is, we are going to build a simple todo-list application in Javascript. You should be familiar with HTML and Javascript and the DOM. You do not need any Ajax experience. Although we are going to use it, all will be abstracted away.

The interface is quite plain, as is the functionality. This is only to demonstrate how to work with CouchDB and not meant as a real application. We could turn this into something nice with some spit & polish.

How it works

We take a top level view here, working our way from the user’s perspective down to the actual code. This ensures we do not screw up the …

When I was a DBA, there were only a handful of must-have tools that I constantly used.  One was a good performance monitor.  Two was a cross-platform admin tool (since I worked with Oracle, SQL Server, Sybase, MySQL, etc.) And three was my data modeling/design tool.  There was absolutely no way I could have done my job in the manner I needed to without those three tools.

Of those three, there were times when I basically lived inside my modeling tool.  Why?  Because:

• Metadata management ? I had to ensure data consistency and enforce standards of data elements used throughout my shop; the modeling tool was the best way to do this. 
• DB design ? simply put, there was no way to more quickly put out a new DB design and forward engineer it into a new physical DB without my modeling tool
• Change management ? when I made changes to the DB, I always wanted to keep …

MySQL has introduced Previews as a new way of delivering features for early testing by our community.

Previews are for testing of features, not of versions. The two previews we offer today are the Falcon Feature Preview based on 6.0, and the GIS Feature Preview based on 5.1. However, the version number as such is not intended by us to set any expectations on when the feature will be in a production version. For instance, Falcon is going into the 6.0 code base, but the GIS geographical data won’t be in before 6.1 (although the preview is based on 5.1).

Previews are by definition a bit “rough around the edges”. …

Today's pearl of wisdom:

MySQL dump files, as produced by mysqldump, are not text files.

A common mistake is to think that mysqldump files are text files. While they superficially look like text files, they in fact are not. This leads to confusion and problems if people try to edit them in a text editor application, which will in many cases cause corruption.

MySQL dump files contain the SQL commands required to recreate the contents of a database (or subset thereof). However, these are SQL commands in arbitrary (binary) encoding and can consist of a mixture of different encodings (e.g. if you have BLOBs). This mixture is not safe to edit with a text editor, which expects a text file to contain character data in exactly one encoding (and will typically guess, ask the user or just use its default to determine which).

Suppose you use utf8 data in your database - then your mysqldump file …

I have finally managed to watch and slightly edit the September 2007 Boston MySQL User Group presentation I did on the MySQL Proxy.

It's geared towards beginners, and has lots of examples, including explaining some of the examples that come bundled with the MySQL Proxy.

Direct Play

Download video (.wmv file, 612 Mb)
Download video (.wmv file, 76.10 Mb)

Enjoy!

Some resources:
Presentation Slides PowerPoint (ppt) or PDF or …

For those who missed the previous announcements, MySQL University is a series of online expert lessons that you can join for free and attend from the comfort of your home or office. The slides are provided in …

I spent way too much time this weekend trying to get the pager stuff in Drupal working for a module I`m playing with.

I had learned a lot from the watchdog module on how paging was supposed to be working and I was trying to do the same with another database. As I got a page limited by the number of records I wanted but I couldn't find any of the fancy next, previous and page number thingies that I wanted.

The watchdog module worked for me and I started stripping the watchdog module till I could actually replace my function with watchdog_overview function. Even replaced the watchdog query with my qeury.. but not such luck.. I couldn't get $output .= theme('pager', NULL, 50, 0); to work.

So as every open source geek does.. I started looking into the code. pager.inc
The header told me the author.. I could mail him and wait …

Arjen wonders why the MySQl Cluster Study book is published on Lulu and not trough MySQL 's traiditional publisher.

Altough I was involved in the creation process of the mentionned book, I have no idea why this decision was made but to me it makes perfect sense. MySQL Cluster is a piece of software that is still going to change a lot in the next couple of months and years.
A book published in a traditional way needs a minimal sales volume in order to be worth publishing. If there even is a slight chance that by the time the book gets published a significant amount of content of the book has already changed traditional publishers shouldn't publish the book. Now over at Lulu.com a book won't be print before a customer orders it. So when the book is being sent to me. I get the current version of the book.. If in 3 months the authors decide to rewrite a chapter or …

While researching partitioning performance (expect an article about this topic soon) I come across the news that the Falcon team has released a Falcon Feature Preview with the latest implementation.
The test I was running was based on 9 server instances , using different combinations of MyISAM, InnoDB, and Archive, with and without partitions.
Since I was at it, I quickly added three instances of MySQL 6.0.4 with Falcon (MySQL Sandbox is really handy in these cases) and added Falcon to the test bench.
As I expected, partitioned Falcon is not particularly impressive, but there was a serendipitous result. In addition to large data warehouse oriented queries, the test fires also 180 OLTP queries, with warm indexes, i.e. after the indexes have been …