Archive for July, 2008

Drizzle – Lightweight DB Based on MySQL

July 23rd, 2008 by Sjan Evardsson

Brain Acker, director of architecture for MySQL has opened the door to Drizzle, a light-weight, high-concurrency database server based on MySQL, targeted at web applications.

The architectural ideas as described in the FAQ:

A micro-kernel that we then extend to add what we need (all additions come through interfaces that can be compiled/loaded in as needed). The target for the project is web infrastructure backend and cloud components.

The FAQ goes on explain the differences between Drizzle and MySQL which include:

No modes, views, triggers, prepared statements, stored procedures, query cache, data conversion inserts, ACL. Fewer data types.  Less engines, less code. Assume the primary engine is transactional.

Michael Widenius, founder and original MySQL developer, explains more about Drizzle in this blog post, including the most interesting piece (to me) – that Drizzle will always contain the most up-to-date InnoDB code, meaning you don’t need to wait around for MySQL 6 or download the plugins from Oracle each year to get the latest and greatest.

While Drizzle is still in development you can check out the code and try it out. Or maybe even get involved and help out. More information on how to do both is available on the wiki.

Why I won’t upgrade my iPhone firmware (yet)

July 18th, 2008 by Sjan Evardsson

Ok, the iPhone 2.0 firmware (actually 1.2.0) is out, and the app store is up and only works with 2.0 firmware and iTunes 7.7 but I won’t do it. Not yet anyway. I am waiting for a jailbreak solution for 2.0 or some additions to the app store before I upgrade. I have been using Zibri’s ZiPhone up to now and actually have quite a few apps that I use on a daily basis.

So, am I just too cheap to pay for apps? No, that’s not it at all. In fact, if the apps I needed were on the store I would upgrade and buy them (and possibly have some support options) and be done with it. While there are some apps that are in the store that I currently use (Shopping List, Twinkle, Book Reader) there are others that aren’t (Terminal, anyone?).

So, until I can jailbreak 2.0 or until the app store catches up with what I actually use, no dice.

Using the COM class for PHP backgrounding in Windows

July 2nd, 2008 by Sjan Evardsson

I was having a difficult time finding a reliable way to run a background PHP process in Windows, when that was called from an active PHP page. In the *nix world it is relatively simple: by using shell_exec() (or the bactick operator) you can redirect the output to another stream or file and the process will run in the background with no blocking. In Windows, however, this doesn’t seem to work well (or at all, depending on what you are calling via shell_exec()). I did find the answer, though, from piecing together info from the PHP documentation for shell_exec() and the COM class.

That, with a little trial and error and I was able to get a PHP page to fire off a command-line PHP process to run an import of several years data into a new reporting schema. Since this import relies on some serious data manipulation it has a tendency to time out for large data sets. So, I set up the command line script to run six months worth of data and before it exits it starts a new background process for the next six months of data. In this way I was able to complete a many-hour process without worrying about timeouts. I did notice that running in the background (actually in an “invisible” command shell) that the process ran slower than when running in the foreground. This was acceptable, however, since the page returns immediately while the processing begins and the application is still usable while the process is running.

Here is how I call it from the page:

if(isset($_SERVER['PWD'])) { // *nix
    $basepath = dirname(__FILE__).'/';
    $php = 'php';
} else {
    $basepath = dirname(__FILE__).'\\';
    // edit to match your installed target environment
    $php = "C:\\php516\\php.exe";
}
ignore_user_abort(true);
set_time_limit(0);
$arg1 = 'foo';
$arg2 = 'bar';
$runCommand = "$php -q {$basepath}my_background_running.php $arg1 $arg2";
if(isset($_SERVER['PWD'])) { // *nix
    // *nix: Use the backtick operator or shell_exec()
    $nullResult = `$runCommand > /dev/null &`;
} else { // Windows: use the php COM class
    // WScript.Shell gives you the command line
    $WshShell = new COM("WScript.Shell");
    $oExec = $WshShell->Run($runCommand, 7, false);
}

I do the same from the background script to call itself recursively right before it exits.

I didn’t find the Microsoft documentation for the Windows Script Host Shell until today during lunch. I found the location in the Practical PHP Programming Online Book where he says to use the Google search “wshell object” msdn which will result in the first link pointing at the MSDN documentation. (I have a feeling it moves around quite a bit, since every link I have run across up to now that points directly at the documentation results in a nice 404 error page at Microsoft.)