I’m still looking for new entries. I get quite a few suggestions, but not all of them make it into quiz questions. Do send in your suggestions!

A column defined as CHAR(x) or VARCHAR(x) will allow you to store up to x characters within each field of that column.

What’s the minimum size of x?

What’s the maximum size of x?

(more…)

The Hitchhacker’s Guide to the MySQL Conference
Ruby/Ruby on Rails Developer’s Edition
Following on from the excellent Hitchhacker’s Guide to the MySQL Conference - PHP Edition by Jay Pipes, I’m doing one for the Ruby and Ruby on Rails developer in you. If you haven’t registered yet, remember, I can provide you a 20% discount code, so make sure you get it from me, via emailing me. Tutorials, are selling out, fast.

The Keynotes
A Head in the Cloud - The Power of …

You must have heard about Falcon, the new transactional engine being developed in MySQL 6.0. And for all the buzz, you may want to have a look at that.
If you haven’t had time to download and install it, now you can give it a try, thanks to db4free, a free MySQL hosting service, created by Markus Popp.

So, if you want to test Falcon today, get a (free) account on db4free and start hacking!
Be careful:

• MySQL 6.0 is still alpha software!
• The default storage engine in this db4free server is Falcon. When you create a new table, if you don’t specify an engine, you will create a Falcon table.

A sample session:

$ …

Nothing to do with MySQL, but I just love observing how technology can make us waste more time. Speech recognition is a wonderful idea, but .... oh just watch this:

Of course, watching this video to the end will cost you about 10 minutes, but it could be worthwhile education. Technology can be very useful. But that doesn't mean that all new stuff is useful, or even suitable for your purpose. I don't think that guy was doing anything particularly complicated or wrong though, and I also commend him for his patience - although you can clearly note his frustration as the experiment progresses ;-)

MySQL Conference & Expo attendees will have the opportunity to enter a drawing for cool prizes by having an expo hall passport brochure stamped at each participating sponsor and exhibitor booth.
Once attendees have obtained all “stamps” they will be entered into the drawing and eligible to win one of several prizes.

And the …

Prompted by the usual Devshed's post, this time about pgAgent, here I am with a small "tutorial" (or maybe just a small collection of screenshots).PgAgent is a great little tool, much like SQLServer's SQLAgent or the built in scheduling abilities of Oracle and MySQL (which is a much nicer solution IMHO), what's weak is the installation and the docs, I mean, why the pgAdminIII installer does ask

My CouchDB presentation at Mailtrust earlier this month got recorded. The video is now online at Yahoo Video. Enjoy!

Update 29.03.2008: Here are the slides. What I said in Some Context still applies.

And while we are at it, these are the slides from my Mountain West Ruby Conference Presentation. Again, Enjoy! :)

My CouchDB presentation at Mailtrust earlier this month got recorded. The video is now online at Yahoo Video. Enjoy!

Update 29.03.2008: Here are the slides. What I said in Some Context still applies.

And while we are at it, these are the slides from my Mountain West Ruby Conference Presentation. Again, Enjoy! :)

My CouchDB presentation at Mailtrust earlier this month got recorded. The video is now online at Yahoo Video. Enjoy!

Update 29.03.2008: Here are the slides. What I said in Some Context still applies.

And while we are at it, these are the slides from my Mountain West Ruby Conference Presentation. Again, Enjoy! :)

I'd been doing some stress testing of my mysql application today, and I was hitting some weird cases. Several transactions were deadlocking - this was expected - but the number of records that got inserted into my table was more than the number that I expected after subtracting errors.

My test was fairly simple:

1. Fork 15 processes
2. Insert and update 100 records in each process, running each INSERT/UPDATE pair inside one transaction
3. ROLLBACK on error

Either the INSERT or the UPDATE was expected to fail due to deadlock, and the whole transaction should have rolled back leaving no record in the table.

Before I go on, I should mention that I was using InnoDB, which does support transactions.

What I expected was that the total number of records in the table + the total number of INSERT/UPDATE aborts due to deadlock should be equal to 1500 (15*100). What …