Gearman examples under Mac OS X

Today I listened in on the O’Reilly webcast Introduction to Gearman by Eric Day of Rackspace. I thought I would follow through on the machine at hand; a Mac with OS X 10.5, however I again got caught up with the gearman PHP extension integration. A look at and older post Getting started with Gearman based on Ubuntu needed an update for Mac.

First I downloaded and installed the latest gearman. This was version 0.12 and includes libgearman 0.7.
You should always check for any more recent updates.

tar xvfz gearmand-0.12.tar.gz
cd gearmand-0.12
sudo make install
ls -l /usr/local/lib/libg*
#-rwxr-xr-x  1 root  wheel  79808 Mar 12 13:33 /usr/local/lib/libgearman.4.dylib
#lrwxr-xr-x  1 root  wheel     18 Mar 12 13:33 /usr/local/lib/libgearman.dylib -> libgearman.4.dylib
#-rwxr-xr-x  1 root  wheel    960 Mar 12 13:33 /usr/local/lib/

gearmand was installed in /usr/local/sbin and gearman installed in /usr/local/bin

Next we needed the gearman PHP extension from pecl

tar xvfz gearman-0.7.0.tgz
cd gearman-0.7.0
sudo make install
# Installing shared extensions:     /usr/lib/php/extensions/no-debug-non-zts-20060613/

Take note of the extension location, as I needed this for the next step.

Php was already installed, which was good.

$ which php

However I found no configuration loaded.

$ php --info | grep -i configuration
Configuration File (php.ini) Path => /etc
Loaded Configuration File => (none)

What exists is a default example only. In order to include the gearman extension I needed to do the following.

$ sudo cp /etc/php.ini.default /etc/php.ini
$ sudo vi /etc/php.ini

# Set extension directory
extension_dir = "/usr/lib/php/extensions/no-debug-non-zts-20060613/"
# Add Gearman extension

And a confirmation.

$ php --info | egrep -i "(configuration|gearman)"
Configuration File (php.ini) Path => /etc
Loaded Configuration File => /private/etc/php.ini
gearman support => enabled
libgearman version => 0.12

Ready now to try out the PHP examples.

SQL Analysis with MySQL Proxy – Part 2

As I outlined in Part 1 MySQL Proxy can be one tool for performing SQL analysis. The impact with any monitoring is the art of monitoring will affect the results, in this case the performance. I don’t recommend enabling this level of detailed monitoring in production, these techniques are designed for development, testing, and possibly stress testing.

This leads to the question, how do I monitor SQL in production? The simple answer to this question is, Sampling. Take a representative sample of your production system. The implementation of this depends on many factors including your programming technology stack, and your MySQL topology.

If for example you are using PHP, then defining MySQL proxy on a production system, and executing firewall rules to redirect incoming 3306 traffic to 4040 for a period of time, e.g. 2 seconds can provide a wealth of information as to what’s happening on the server now. I have used this very successfully in production as an information gathering an analysis tool. It is also reasonably easy to configure, execute and the impact on any failures for example are minimized due to the sampling time.

If you run a distributed environment with MySQL Slaves, or many application servers, you can also introduce sampling to a certain extent as these specific points, however like scaling options, it is key to be able to handle and process the write load accurately.

Another performance improvement is to move processing of the gathered information in MySQL proxy to a separate thread or process, removing this work from the thread execution path and therefore increasing the performance. I’m interested to explore the option of passing this information off to memcached or gearman and having MySQL proxy simply capture the packet information and distributing the output. I have yet to see how memcached and/or gearman integrate with the Lua/C bindings. If anybody has experience or knowledge I would be interested to know more.

It is interesting to know that Drizzle provides a plugin to send this level of logging information to gearman automatically.

Getting started with Gearman

Gearman is an open source generic framework for distributed processing. At OSCON 2009 I attended the Gearman: Build Your Own Distributed Platform in 3 Hours tutorial.

While it’s very easy to install Gearman, and follow the first example, if you missed the all important additional PHP steps listed on just one slide you may be left with the “‘Class ‘GearmanClient’ not found” error.

The following are detailed instructions for the installation and configuration of Gearman and PHP on Ubuntu 9.04 Jaunty.

Add the Drizzle PPA to get pre-packaged versions of Gearman.

cp /etc/apt/sources.list /etc/apt/sources.list.orig
echo "deb intrepid main
deb-src intrepid main" >> /etc/apt/sources.list
apt-key adv --keyserver --recv-keys 06899068
apt-get update

Get the gearman packages

apt-get install -y gearman gearman-job-server gearman-tools libgearman1 libgearman-dev libgearman-dbg libgearman-doc

Get the German PHP extension.

tar xvfz gearman-0.4.0.tgz
cd gearman-0.4.0/
make install

If phpize is not available then you are missing the development packages.

$ apt get php5-dev

You also configure PHP to load the extension. This will vary on different Linux environments. In this case.

echo 'extension=""' >>/etc/php5/cli/php.ini

Verify the PHP Gearman extension is configured.

$ php --info | grep gearman
gearman support => enabled
libgearman version => 0.8

Now you are ready for working with the Gearman PHP examples.