Back in May Dan Morgan was kind enough to invite me to do a guest lecture at the University of Washington about “Data Warehousing Basics.”  After having emailed these slides as a decent overview to a few customers lately, I realized they’d probably be useful online.  It is obviously a little light on content (their just slides) but they do provide some good “high level views” of dimensional modeling/DW/BI in general.  My employer, Pentaho, was generous enough to allow me time to build this presentation for the students at UW for which they, and I are grateful.  THANK YOU!

The online version: Univerisity of Washington Guest Lecture May 9
The PDF of …

Open source is democratic, open, real.

While I have a good sense for which Tech Tips would be useful, I’d also like to ask the community for what tips they’d like to see written up:

• Mondrian: Star Schema to OLAP cubes
  A very basic Star Schema with a Fact and Two Dimensions show how this is built into a Mondrian cube and how to built a “Pivot view” Pentaho report.
• Mondrian: Advanced MDX
  Sets, top, running totals, etc
• Kettle: Portable ETL
  Showing how to use paramater injection to make your Kettle solution (Jobs and Transforms) executable inside of Pentaho.
• Kettle: Custom rollups using Excel
  Showing how to build a dimension, reporting table, etc using a very easy to use interface for business users.
• Reporting: List of Values
  Show how to use the most unfortunately …

The 451 Group is calling for change in the business models of the so-called "stack providers." (OpenLogic, Spikesource, Sourcelabs, etc.) Dave and I have seen this coming for some time, and the vendors, themselves, have, too, as each has been tweaking its model over time.

(Dave has never been a big believer in Spikesource (here is his first assessment), though I've been more sanguine, and I've also skewed pro OpenLogic and BitRock.) …

James Montebello, a friend, a mentor, a fantastic engineer, and the person who introduce me to mySQL in 1999 passed away August 24, 2006.

I write this today in dedication to a great man. I also write this in appreciation for all the time we had together, and for guiding me on what are the right things to do.

He was among the 1st to believe in my designs

James you will be deeply missed.

I posted some Basic Documentation for MySQL Index Analyzer including a simple example. This is intented to get started with the tool without having to read the code.

Any ideas and suggestions for improvements are appreciated :)

Frank talks about Storing Passwords in MySQL. He does, however, miss something that’s really, really important. I’m talking about the salting of passwords.

If I want to find out what  5d41402abc4b2a76b9719d911017c592 or 015f28b9df1bdd36427dd976fb73b29d MD5s mean, the first thing I’m going to try is a dictionary attack (especially if i’ve seen a table with only user and password columns). Guess what? A list of words and their MD5SUMS can be used to very quickly find what these hashes represent.

I’ll probably have this dictionary in a MySQL database with an index as well. Try it yourself - you’ll probably find a dictionary with the words “hello” and “fire” in it to help. In fact, do this:

mysql> create table words (word varchar(100));
Query OK, 0 rows …

I recently discovered that I’d made a huge blunder in the Partitioning Limitations section of the MySQL 5.1 Manual. I’d had the idea that unique keys don’t effect your choice of partitioning columns unless there’s no primary key.

My latest revision of the documentation for this limitation isn’t much better.

Then, as I was sitting here just now trying to persuade my daughter that she really ought to have something for lunch besides marshmallows, it came to me.

It’s very simple, really.

For any user-partitioned table in MySQL 5.1:

1. If a table has any unique keys, then all columns used in the partitioning expression must also be part of any and all of these keys.
2. By definition, a primary key is a unique key.
3. If the table has no unique keys, then you don’t have to worry …

conference, database, foss, free conference, mysql, mysqlcamp open source

On Wednesday night, I did some consulting, and it ended up taking twice as long as I thought it would. So I am rewarding myself by going to MySQLCamp!

Speaking of which, I updated the home page, adding explicitly that registration is free, and a section on …

So, a while back, I did some tests with the mysql, mysqli and PDO extensions. In those tests, I found PDO to be much slower for selects than mysql and mysqli. Half as slow in fact. Santos mentioned these tests in a post about SDO. Wez has pointed out that the mysql API does not use the query cache when using prepared statements. Apparently, under the covers, PDO uses prepared statements for all queries. At least that is what I am taking from this. My tests showed the same speed whether I used the PDO prepared syntax or not.

So, I decided to try Wez’s trick of emulating prepared statements to see how PDO did. The results were interesting. Not sure if these are the “fair comparisons” that Wez wants to see, but I …

I had need to goto the Wikipedia this morning to review the terminology of something, and on the front page in Today’s featured article is Mercury. Being a tad curious given I’d heard only on the radio a few hours ago that Pluto was no longer a planet in our Solar System, I drilled down to the bottom to check references to other planets (quicker then searching). So at the bottom I found the following graphic and details of The Solar System Summary.

Well blow me down, they didn’t waste any time there. Pluto is no longer a planet in our Solar System. It is now categorised as a …