In a previous post, I mentioned the availability of the dtrace extension for Cool Stack's PHP.  Using this extension and the Cool Stack MySQL, it is possible to analyze the performance of your application running on this stack. At JavaOne, we demoed this using the open source MediaWiki and SugarCRM applications.  dtrace is especially useful in analyzing complex multi-tier applications like AMP. Thanks to Angelo Rajadurai for the creation of the scripts that I describe below.

Analyzing PHP calls

So, let's look at a simple dtrace script that counts how many times a particular PHP function is called :

#!/usr/sbin/dtrace -Zqs

php*:::function-entry
/arg0/
{
        @[copyinstr(arg0)]=count();
}

You can copy the …

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 …

Ronald Bradford has published the 47th edition of Log Buffer, the weekly review of database blogs, on Technical Notes and Articles of Interest. Get in touch if you’d like to edit and host an edition of Log Buffer on your own blog. The Pythian Group Blog is widely read, so being a part of the [...]

Log Buffer #47: a Carnival of the Vanities for DBAs
June 1st, 2007 - by Ronald Bradford

Welcome to the 47th edition of Log Buffer, the weekly review of database blogs. No time to wait, lets read more about this week’s database blogging activities.

The PostgreSQL Conference for Users and Developers wrapped up this week and Peter Eisentraut gives us a review including the lightning talks and wrap-up session with a charity auction in PGCon Day 4. Meanwhile Alex Gorbachev is at Miracle Scotland Database Forum - Day One, sounds like from his post there is a lot …

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? …