The latest from the MySQL community

MySQL will be hosting its first-ever Federal DBA Day - a free, one-day boot camp for experienced Oracle DBAs interested in learning how to deploy and manage MySQL in a production environment. The event will take place on Thursday, January 24, 2008, at the Ronald Reagan Building and International Trade Center in Washington, D.C. For more information and to register, visit: http://www.carahsoft.com/events/mysql/01-24-08/mysql01-24-08.php?ref=mysql

Over at ITToolbox Tarry has another blog . He posted an article where he tried to debunk some myths about open source. I feel he needs some help there :)

Let's start with his second Myth , Open Source is Free. Off course it isn't , you need to invest your own time to get familiar with it or pay other people to use it. Compare it to building a house ... you can build one if you have the skills and the time , but you still need to pay for the bricks and the mortar, or you can pay someone who has the skills to build one for you. With software there used to be a similar thing. You could buy software, then install and configure it yourselve, or you could hire someone more skilled than you to install and support it when you run into problems. Now take away the fact that you have to …

Dear lazyweb,

I want to mine a code repository for data to map past bugs to sourcecode files.

I have written a small PHP script (the initial version of the script can be found here) to import the relevant data from a Subversion repository into the following tables of a relational database:

bugs            changes         paths
--------        --------        -------
bug_id          path_id   <-->  path_id
revision  <-->  revision        path

What I need now is two queries to ask the database for

• paths that are most commonly changed during bugfix commits and
• paths that are commonly changed together …

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 …