I frequently get questions along the lines of "how many transactions per second MySQL can do" or "how many servers I need to handle 100.000 users" or "which hardware would be enough to handle my 40GB" database.

There are two things which are very interesting about these questions which make them funny and annoying at the same time

1) People asking these questions demand the answer. It could be internal Sales and Marketing people or even customers saying they typically get the answers from other vendors.

2) The best answer to this question will not be a number but something like "it depends". Seriously you need much more information than given in this example to give estimate which is correct at least to the order of magnitude.

Seriously in MySQL Consulting practice it would not be exception to have 1-2 orders of magnitude performance increase just by proper tuning - this means even application implementation …

I've been listening to a number of podcasts when I'm in my car. One of my favorites, This Week in Tech (or "TWiT" as its known) hosted by Leo Laporte and featuring a case of regulars including Kevin Rose from Digg, John Dvorak, Patrick Norton and others.  Leo is clearly a fan of technology and his enthusiasm and self-deprecating humor while reviewing the week's tech stories makes for a good listen.

Recently, TWiT has spun off a new show called FLOSS Weekly (get it?) featuring Chris DiBona (pictured above), open source guru over at Google.  Although the first few episodes were a bit slow, it's now starting to find its voice.  Leo Laporte co-hosts many of the shows helping to provide a better balance and preventing the show from just being too mcuh of an …

I used XDebug to profile the behavior of Drupal, and to study the interaction with the database server. I aggregated the profile information of 100 requests to the main page using the "Apache, mod_php, PHP4, APC" configuration used for previous benchmark experiments. More information about my experimental setup is available at that page. XDebug generates a trace file with all the profile information which I visualized using KCacheGrind.

Drupal has a page cache mechanism which stores dynamically generated web pages in the database. By caching a web page, Drupal …

I used XDebug to profile the behavior of Drupal, and to study the interaction with the database server. I aggregated the profile information of 100 requests to the main page using the "Apache, mod_php, PHP4, APC" configuration used for previous benchmark experiments. More information about my experimental setup is available at that page. XDebug generates a trace file with all the profile information which I visualized using KCacheGrind.

Drupal has a page cache mechanism which stores dynamically generated web pages in the database. By caching a web page, Drupal does …

Yep, here's another weekend challenge. It's not a regular thing, I just post one when I think of something and there's no prizes except eternal glory!

This time, try and come up with a nice clean and efficient way of maintaining ordered lists. That is, all items in a table, or groups of items, should be ordered *inside* that table/group relative to eachother, and it should be possible to move them around (i.e., change that order and insert new or existing items at any point) without too much hassle. That last requirement is probably the main thing you will want to think about...

Naturally, you shouldn't muck around with the auto-inc ID, you know how I feel about that ;-)

Good luck, and have a nice weekend!

I am ready to leave for the FrOSCon Conference, taking place on Saturday and Sunday in St. Augustin/Germany.

Here's the program that contains many MySQL related sessions.

I hope to meet many MySQL people there ;-).

MySQL doesn’t allow referring to a table that’s targeted for update in a FROM clause, which can be frustrating. There’s a better way than creating endless temporary tables, though. This article explains how to update a table while selecting from it in a subquery. The problem Suppose I want to update a table with data from a subquery that refers to the same table. I might want to do this for a variety of reasons, such as trying to populate a table with its own aggregate data (this would require assignment from a grouped subquery), updating one row from another row’s data without using non-standard syntax, and so on.