The new issue of the Python Papers is out.  It includes a small article I wrote called: Screen Scraping Web Pages

The issue can be downloaded here:  The Python Papers, Volume 2, Issue 4 (pdf)

This tutorial shows how to programmatically retrieve a stock quote from Google Finance.  It uses Python's high level Web API and screen scraping with regular expressions.

I was recently interviewed for the article:
Python Experts - Why They Do Python

I don't think I am even close to an "expert", but it was nice being asked to participate.

A performance engineer is a little bit of a jack-of-all-trades.  Rather than focusing on small technological niche, performance testers must have a very wide range of technical skills to understand the inner working of a complex system under test.

As far as skill go, Scott Barber has said that you need to be a "mid-level everything":

"Become a "Mid-Level Everything" – Developer, DBA, Network Admin, Systems Admin, Architect, Business Analyst, etc."

If you want to become proficient in analyzing system performance and scalability, there are many technical areas you should study.  Here are some skills I have found to be invaluable in my success as a performance engineer:

Performance Concepts:

• Methodology
• Load Generation Tools
• User/Workload Modeling
• Results Analysis (Latency, Throughput, Metrics)
• Bottleneck Detection
• Code Profiling
• Scalability
• Concurrency
• Charting/Graphing
• Statistics

Operating Systems and Servers:

• Monitoring (CPU/Network/Mem/Disk/etc)
• System Tuning
• Web/Application/Middleware Server Tuning
• System Administration
• Virtualization
• OS Concepts (CPU Scheduling, Memory Management, etc)

Database:

• SQL
• Stored Procedures
• Monitoring
• Tuning

Network:

• Topology
• Monitoring
• Load Balancing
• TCP/IP
• HTTP
• Packet Sniffing and Protocol Analysis
• Caching
• OSI Model

Programming:

• Proficiency in at least on general programming language. Preferably a dynamic scripting language (Python/Perl/Ruby/etc)
• Code/Algorithm Analysis

(Note: There are lots of "soft skills" a performance tester would need to be successful. This post focuses only on technical skills)

Sometimes music is treated as art, not as a vehicle for hoarding money and restricting consumers.

This is exemplified by the copyright policies of certain performers.  Here are my favorite policies from some influential acts:

Grateful Dead's Mp3 Policy:

"The Grateful Dead and our managing organizations have long encouraged the purely non-commercial exchange of music taped at our concerts and those of our individual members. That a new medium of distribution has arisen - digital audio files being traded over the Internet - does not change our policy in this regard."

Woody Guthrie's Standard Copyright Notice:

"This song is Copyrighted in U.S., under Seal of Copyright # 154085, for a period of 28 years, and anybody caught singin’ it without our permission, will be mighty good friends of ourn, cause we don’t give a dern. Publish it. Write it. Sing it. Swing to it. Yodel it. We wrote it, that’s all we wanted to do."

The 3 most important caveats to be aware of when dealing with statistics:

• Correlation does not imply causation.
• You can make statistics tell you nearly anything you want.
• Statistics without proper context are meaningless.

Open Source Testing is a great resource that lists most of the open source tools available to testers.  The site is run by Mark Aberdour and has been around since 2003.

Mark's contributions to the testing and open source communities have been very valuable.

Well... he just stepped it up a notch by posting details of his new Community Donations Program:

"during 2007 Open Source Testing has begun to generate fairly regular revenue. It has always been my aim, should the site become commercially viable, to put some profits back into the open source community. I will be aiming to make bi-monthly donations (funds providing) to open source testing projects and open source organisations of my own choosing. The donations will not be earth shattering, but whether they cover hosting and hardware costs, contractor costs, publicity, trips to events or just some extra motivation, they will certainly make a difference."

Great work Mark!