I've been following the comments to Jamie's latest post and I have to say that most of the people who left comments are not thinking logically about this.  Most (not all) are outraged that Microsoft would try to prevent Jamie from enabling his most excellent TestDriven.Net product on the Express line of products (Visual C# Express, etc).

As a consumer I would love to be able to use plugins in the Express products.  I use Visual C++ Express to code on the MySQL server frequently.  However, I'm smart enough to realize when I've been given something for free. Let me say this slowly and clearly:  Microsoft is a business, not a public service.  They didn't have to make the Express products available at all.  It takes a great deal of time and money to build something as complicated as these …

Counts, we all love to show counts in our applications. Under a high traffic website, it's visually appealing to show a big number. But the cost of generating that big number realtime can be very expensive on our mySQL backend.

For example:

$sql = SELECT COUNT(*) FROM VERY_BIG_TABLE WHERE key_part1=NUM AND no_key IN (1,2,3) AND key_part2=NUM

Would you think this is fast? In a dev environment yes, but this query has to get the exact row count that meets the requirements of the WHERE clause.

In many cases we use a count to solve a BOOLEAN term in our code, for example

$count_result = db_fetch($sql)

if ($count_result) {
   // do something
} else {
   $SHOW_ERROR = 1;
}

Don't use a count for this purpose. Just do something like

$sql = …

As Roland pointed out, recently a bunch of us took the MySQL Cluster Certification Exam. I was strongly encouraging people to take it (and, in fact, got the majority of people to take it… except those working on urgent customer issues or were rather new to the product).  That’s one of my cunning plans (number 8 IIRC) - to have anybody doing anything to do with MySQL Cluster inside MySQL AB to be certified (in cluster, not insane).

Response from the exam is overwhelmingly positive and as it’s new, afterwards I discussed a few questions with Roland (in fact, all the ones I got wrong). The (good!?) news is that I legitimately brain-farted on some.

As for bragging rights… I currently share the top score. I’ll also (happily) buy a (large) beer …

How can a query like "SELECT * FROM tbl WHERE col IS NULL" return a row where the column has a (non-NULL) value? Read on to find out.

Yesterday morning, I had an initial face-to-face meeting with a prospective client. We met at the Victrola Cafe. He's putting together a pretty neat Web2.0 custom app. My first task for him will be writing a little process that monitors a particular public database and writes changes into S3, to start capturing a historical timeline. There is a great deal of additional AWS, DB, and web client programming work I am qualified to do for him.

Today, I pulled together a software developement contractor contract, rewrote a bit of it to be aware of open source licencing "stuff", and then emailed it off to him, along with my rate and time estimate.

Google Gears release is just plain nifty.

Jump just a little bit forward in time to Google making both GMail and Google Calendar available. Suddenly you have offline usage for two of their main products (and frankly this is what might make me finally consider using their Calendar application, which would be great for my friends since they could then finally know when I am in town or not).

For the database world there are very practical applications in synchronizing data sets to local storage so that users can either do data entry locally for later storage, or business intelligence.

We have been limited by max cookie size for a bit too long, this really changes that.

One of my fears? …

A few weeks ago I noticed that the new version of Yahoo! Widgets/Konfabulator now supports an embedded client database, SQLite. This got the gears in my brain whirring -- what could you do with a desktop widget that sports a embedded database engine? Converting the Approver.com desktop widget into something more functional (maybe with the ability to replicate files from client to server) comes to mind, but there are tons of other things you could do.

The interesting new Google Gears product also rocks SQLite (as a way to facilitate the creation of offline web applications). Not to be outdone, Mike Chambers of Adobe blogged last night that the Apollo …

People are always surprised to find out just how distributed Alfresco is as an organization. Aside from a small hive in London, it's hard to find more than two Alfrescans in the same city. The same is largely true of MySQL and a number of new open source companies (MuleSource comes to mind). At Alfresco in the US, we have people in Austin, Boston, San Francisco, Denver, Salt Lake City, Atlanta, and New York City. Even where we have people in the same cities (there are now four of us in Salt Lake City), we don't have offices and only... READ MORE

Erik Hoekstra, from Daisycon, has pointed out this problem related to Replication in general and with a specific example on MySQL Cluster and Replication in 5.1.

In the manual for 5.1 there's an entry about scripting the failover for MySQL Cluster Replication.

In this part of the manual they speak about fetching the needed variables, like the filename and position, and place them into the CHANGE MASTER TO statement.

The example is here:

CHANGE MASTER TO
MASTER_LOG_FILE='@file',
MASTER_LOG_POS=@pos;

I'm now trying to do the following:
On a slave I've created a Federated tables, 1 pointing to the current master, and 1
to the stand-in master, should the current master fail.

Federated table 1, let's say F1, is …

Today I published the DGCov tool on the MySQL Forge.

DGCov is a neat tool that I implemented last year for use internally at MySQL, an old idea of Monty's.

The idea is to help developers to check that a new patch for the server code has received adequate testing before pushing it to the main tree. The GCC compiler has the gcov tool that can check which lines of the source code were never executed even once. But suppose you change a few 1000 lines across a big source base like MySQL. Then GCov output is not all that useful, since it will report tons of lines as not executed, and it is difficult to manually check which of those lines were touched by your patch.

The DGCov tool takes the GCov output and filters it so that it only shows those lines that were touched by the patch being checked. This output is immediately applicable to the work done …