First, a retraction, it turns out that the performance problem with datatimes in the previous article wasn’t due to high cardinality (I speculated too much here), but due to a type conversion issue.  From a helpful comment from Victoria Eastwood of Infobright (a good sign for a startup), the Infobright engine considered ‘2001-01-01’ to be a date, not a datetime, and it couldn’t do a conversion to a datetime.  Instead it pushed the date filtering logic from the Infobright engine to MySQL.  Effectively, the slow queries were a table scan.   The solution is to add the 00:00:00 to the dates to make them datetimes.  

With that in mind, here are some much better numbers for Infobright.   For Infobright this query took 0.05 seconds. 

1) Select sum(unit) from Sale where purchaseDate >= '2001-04-01 00:00:00' and purchaseDate < '2001-05-01 00:00:00'

This compares very …

Check out http://dev.mysql.com/downloads/cluster/! Finally, there are binaries for MySQL Cluster 6.3!

Moreover, read my previous post :)

Cleversafe tackles data security and reliability and uses open source and appliances to drive usage and revenue READ MORE

First, AddThis.com (where I was the director of IT) and Clearspring have merged! A side effect of that is that I’m now (happily, on purpose, by choice) a full-time consultant! I’ll have a web site up soonish. Until then, check back here for updates. If you’re a tech firm who needs help, and don’t mind remote workers, send mail to bkjones at Google’s mail service (.com).

Some folks thought I’d passed away due to the uncharacteristic lull in posting frequency on this blog. I’m very much alive — but working for a startup and maintaining a consulting business simultaneously is hard, especially when two large projects fall into your lap at the same time. So what have I been up to?

Well, as part of the now-public merger between the company I worked for and the new company, …

I have worked with backups and network backup systems for about 13 years now. I decided to investigate what it would take to write such a system, using MySQL for the backend database.

The first thing I discovered is that traversing the directories is a slow process, though many times faster than actually backing up the files, but still slow. I discovered a nifty subroutine called nftw that recurses into directories and gives a stat structure and other information for each file found. Much, much faster, and you get the stat structure to boot.

The other thing I have been investigating is a poor man's data de-duplication. I've run some experiments on servers here at work, creating a hash of each file. After looking at millions of files, I settled on MD5 hash, with no duplicate hashes found so far.

I will post later about the code to recurse into directories, and the hash stuff and some timings and why I chose …

Although Colin Charles has taken over the illustrious duties of Program Chair for the MySQL Conference and Expo 2009, I'm participating in the conference as a member of the submission voting panel along with over a dozen other folks. The deadline for submitting abstracts is October 22nd. Yes, that's 23 days away. So, if you haven't submitted yet, please consider doing so. Giuseppe and others have done a good job outlining guidelines for you to follow in order to get a submission accepted. There is an …

A short post to direct people’s attention to and solicit comments on the following from someone who is admittedly a hero of mine, Richard Stallman:

But Richard Stallman, founder of the Free Software Foundation and creator of the computer operating system GNU, said that cloud computing was simply a trap aimed at forcing more people to buy into locked, proprietary systems that would cost them more and more over time.

“It’s stupidity. It’s worse than stupidity: it’s a marketing hype campaign,” he told The Guardian.

“Somebody is saying this is inevitable – and whenever you hear somebody saying that, it’s very likely to be a set of businesses campaigning to make it true.”

The 55-year-old New Yorker said that computer users should be keen to keep their information in their …

One of the great things about working on great products is that you get to meet such intelligent and interesting people. I can apply that to everybody that I work with, but there are some teams where not only are they working on great products, they are also all great people just to spend time with.

I have had the good fortune of working with the MySQL Enterprise Monitor team as an advisor, and more recently in writing the documentation, for the last 18 months. We’ve had some great fun at meetings in Amsterdam, Heidelberg, Santa Cruz and recently Riga. In the meeting rooms we are professional, but fun. But in the evenings we’ve gone out and just had plain good fun. Unless you’ve experienced a full day, or even week, of non-stop meetings for 12 hours a day you have no idea how important it is to kick back in the evenings. That, as a team, we are still able to have a good time at the end of each day while still being in the same room …

Changes (as compared to 2.72) include:

Features:
* Added new monitoring module displaying disk usage information for databases and tables.
* Display of slow log data in Log Analyser had added more information (about when query occured, information about number of rows examined and sent)

Bug fixes:
* When a multibyte character was used in a connection name the display would garble and also the connection could not be deleted from GUI.
* When connection was not available the caption for counters should display “n/a”. Since 2.71 it would instead display a string exposing an internal …

The summer is over, but as a small consolation there is a new version of XAMPP. And this time, we were able to update all existing four XAMPP versions.

In this version we updated: MySQL (5.0.67), PHP (4.4.9), and phpMyAdmin (2.11.9.2). The Solaris version even got a total of 14 packages updated.

Get the downloads and more details on the specific platforms XAMPP project page.