With my continued investigation of evaluating alternative data management with cloud computing options, I’m now evaluating Amazon Simple DB. Still in restricted beta, it helps to have a friend on the inside.

Working through the Getting Started Guide (API Version 2007-11-07) was ok, annoying in parts. Here are some issues I found. I was working with Java as the programming language.

• The Docs enable you to view the language syntax in Java, C#, Perl, PHP, VB.NET, ScratchPad. You can also restrict the view to a specific language. A rather cool feature. One observation is there is no Python, which is rather ironic as my first investigation was …

I just posted slides from a talk I gave at a Facebook application developer conference in Las Vegas this weekend. The talk is titled Outrun the Lions. Our customers run several of the top 10 applications on Facebook right now (as measured by the number of active users), and I revealed the secrets to building applications that can handle the load.

The title is a pun on the story about lions and gazelles in Africa (every day, a gazelle wakes and knows it must outrun the fastest lion; every day a lion awakes and knows it must outrun the slowest gazelle). If you're a Facebook application developer, the lion is not your competition. It's your users. They will love you if you do a good job. They will love you so much that the load will destroy your application, and then they'll go away and they won't come back. (Another speaker at the …

I actually wrote about this a bit in a comment on Paul's blog, but thought it time to re-hash the issue since it came up again during a friendly discussion at work (PostgreSQL was mentioned :)

Why doesn't MySQL have an custom field types? Or perhaps I should call them complex field types, but either way, why no love for anything but primitive strings and numbers?

Take an IP address, for instance. It is an unsigned 32-bit integer. Yes, we can store it in its raw form and use the INET_NTOA() and INET_ATON() functions. The problem seems to be, however, that many people don't use those functions and opt to use a varchar() instead. Ugly, wasteful, and, in some cases, slow; but simple. The INET_* functions work well, and, while you can mask this behind VIEWs and stored procedures, it seems to make things more complex and …

I have a somewhat strange relation to parser since a while. Like everyone I started with writing little parsers by hand and bounced several times against yacc and flex failing to get around their very own syntax.

Then I discovered lemon and used it in lighttpd for the configuration and HTTP parsing, finally a parser syntax I could read. But it still was a split between lexing and parsing.

Along the the way there was ragel with its wonderful dot-output to visualize its state-engine, very neat and a mixed lexer and parser.

2-3 weeks ago I finally stumbled over LPEG and I'm happily writing parsers now. Like a simple one that can parse complex SELECT queries and …

Mit einer der nächsten Versionen von XAMPP ist eine Überarbeitung der Demo-Seiten geplant. Die sind nun auch schon 6 Jahre alt und schreien förmlich nach einer Auffrischung.

Und damit wir uns nicht nur von unseren persönlichen Vorlieben leiten lassen, suchen wir nun für eine Befragung zu deren Usability freiwillige Teilnehmer.

Vielen Dank an alle Teilnehmer und ganz besonders an Karin Kunkel, Sonja Uhl und Constanze Weiland, die diese Umfrage für uns durchführen.

How do you version your database schemas?

There are quite a lot of different options. On some very small / trivial applications developed by just one person, it might be acceptable to use ad-hoc queries (maybe with a GUI) to manage the schema - but this runs the risk of development and production schemas becoming out of sync (or rather, out of sync with their respective versions of code).

Requirements are typically

• Schema changes are held with the rest of the software in a SCM system
  
• Schema changes can be made in one development environment and will be correctly propogated with code to other development and production environments as required
• Schema changes can be rolled back (if for example, a deployment contains a serious bug)

There doesn't seem to be an easy answer for this one.

Our teams do something like:

…

On Windows® - but I guess it’s the same on another O.S. that does not support cluster - I noticed the following behavior when trying to execute a CREATE LOGFILE GROUP syntax like this:

CREATE
 LOGFILE GROUP `test`
 ADD UNDOFILE ‘test’
 INITIAL_SIZE = 33M
 UNDO_BUFFER_SIZE = 8M
 ENGINE = NDBCLUSTER;

In v.5.1.25-rc, v.5.1.24-rc and v.5.1.23-rc, only SQL warnings are shown:

mysql> CREATE
    ->  LOGFILE GROUP `test`
    ->  ADD UNDOFILE ‘test’
    ->  INITIAL_SIZE = 33M
    ->  UNDO_BUFFER_SIZE = 8M
    ->  ENGINE = NDBCLUSTER;
Query OK, 0 rows affected, 2 warnings (0.01 sec)

mysql> SHOW WARNINGS;
…

I had a talk with a friend of mine, yesterday. He recommended to me that I should move away from MySQL and become more proficient with Oracle or MS SQL. The reason for this is that he argues that there is a higher chance I can find a job working in a company that uses a commercial databases (and also higher paid position) then I could for a company that uses an open-source database.

His logic was that:
If a company is already paying for a commercial database, they would have no problem paying some more for someone to maintain it or develop on it.
I started thinking about what he said to see if its true. Not so long ago, I worked on a project for big car manufacturer in China and they used Oracle databases. They had the resources to hire quite a few PL/SQL developers for something relatively simple (but I am pretty sure those PL/SQL developers are still working on it as they get paid by the hour).

On the …

I have a somewhat strange relation to parser since a while. Like everyone I started with writing little parsers by hand and bounced several times against yacc and flex failing to get around their very own syntax.

Then I discovered lemon and used it in lighttpd for the configuration and HTTP parsing, finally a parser syntax I could read. But it still was a split between lexing and parsing.

Along the the way there was ragel with its wonderful dot-output to visualize its state-engine, very neat and a mixed lexer and parser.

2-3 weeks ago I finally stumbled over LPEG and I'm happily writing parsers now. Like a simple one that can parse complex SELECT queries and …

mysqlsla v2 is finally “done” and released. About 3 months ago, when v1.8 was released, I said it would be coming “soon,” but time just flew by and here we are. Oh well. In any case, the v1 branch is dead to me and v2 is all the rave (at least for me). If you don’t care about the differences and all you want is your default top 10 report from a slow log, for example, then all you need to know is: mysqlsla -lt slow SLOW_LOG

For those interested in what has changed to warrant a new major version number, here’s the briefing of changes/overhauls:

1. Almost ALL new command line options (–log-type a.k.a. -lt is the most important); see the documentation
2. Customizable reports. In v1 the report was hard-coded. Now with -rf FILE you can format your own report. See the …