Web Performance Matters

I was going to write about performance and availability today, but this was not the post I had in mind. Technorati sidetracked me. So I'm going to write about Usability instead. Because Technorati provides a good counter-example -- how not to build a usable Web application that satisfies and retains customers.

In Web Usability: A Simple Framework, I described a way to think about Web site or Web application usability.

In a second post, The Dimensions of Usability, I presented the graphic shown here, and discussed the four dimensions in a bit more detail.

These four dimensions are not alternative functional goals, to be weighed against one another and prioritized. Web application effectiveness is a four-step challenge:

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Coding Horror

The best products are designed with Human Factors in mind. That's why I often write about Web design and usability in my Web Performance Matters blog.

Jeff Atwood recently published Thirteen Blog Clichés, a post summarizing his "opinions about what makes blogs work well, and what makes blogs sometimes not work so well." These are presented as a list of common mistakes to avoid (or anti-patterns). If you have a blog, or are designing one, you've probably read similar articles before. Even so, Jeff's checklist is worth a look. All such lists tend to contain a core set of common guidelines to follow and/or pitfalls to avoid, but some of Jeff's opinions step outside the conventional wisdom.

Because I maintain two blogs -- Web Performance Matters and UpRight Matters -- I decided to rate both blogs against Jeff's criteria. Here are edited versions of his recommendations, and my responses. To read Jeff's full discussions of each guideline, see the original. And for the full story, see the many responses posted by Jeff's readers in the comments section of his blog.

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My recent post, Asynchronous Architectures [4], summarized a presentation by Werner Vogels at the 2007 QCON conference in London.

A subsequent post by Kent Langley in his new ProductionScale blog -- entitled Getting Rid of the Relational Database -- supports the arguments advanced by Vogels.

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Latency, Bandwidth, and Station Wagons focused primarily on the limitations of network bandwidth, and the time required to transmit massive data volumes. While that is an interesting topic, and one that produces some surprising results (like the fact that FedEx is still faster than the Internet), it is not particularly relevant to the subject of Web performance, which depends on the time required to transmit many small files.

My post highlighted It's Still The Latency, Stupid, by William (Bill) Dougherty in edgeblog. Bill's title pays homage to a famous 1996 article by Stuart Cheshire about bandwidth and latency in ISP links, It's the Latency Stupid.

Over a decade later, Bill points out, Cheshire's writings are still relevant: One concept that continues to elude many IT managers is the impact of latency on network design ... Latency, not bandwidth, is often the key to network speed, or lack thereof. This is especially true when it comes to the download speeds (or response times) of Web pages and Web-based applications. In this post I explain why, providing some supporting references and examples to support my argument.

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One concept that continues to elude many IT managers is the impact of latency on network design. 11 years ago, Stuart Cheshire wrote a detailed analysis of the difference between bandwidth and latency in ISP links [It's the Latency Stupid]. Over a decade later, his writings are still relevant. Latency, not bandwidth, is often the key to network speed, or lack thereof.

That's from It's Still The Latency, Stupid by William (Bill) Dougherty, writing in edgeblog on May 31, 2007. Bill follows that opening paragraph with a very readable explanation of the vital importance of latency (round-trip time) as a factor affecting performance in TCP networking. He uses what he calls the Sandbag Problem to illustrate his points:

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Clustering and distributing Java applications has never been easier than it is today. As a result, writing good distributed performance tests and tuning those applications is increasingly important. Performance tuning and testing of distributed and/or clustered applications is an important skill and many who do it can use a little help.

That paragraph introduces a new series of four posts about how to approach testing for distributed Java applications by Steve Harris of Terracotta, who blogs as DSO Guy. Steve frames his guidelines as anti-patterns -- in other words, pitfalls or "commonly-reinvented bad solutions to problems" to be avoided [see Wikipedia].

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Where performance is concerned, you should never underestimate the importance of the customer's perception. Usability specialists know this, because they focus on quality metrics that cannot be measured except by asking (or observing) customers. But technical professionals, who focus on more concrete metrics, tend to ignore issues of user perception.

Yet no matter how much time we spend systematically and objectively designing, measuring, and tuning our products to make sure that they really do run fast enough, in the end customer satisfaction is always a very subjective matter.

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Most hosted Web Analytics vendors charge you according to page views -- not unreasonable since each view is a call to their server and a new record in their database. But what happens when Ajax and other rich applications eliminate the notion of a "page"?

That's from Web 2.0 Changes Web Analytics Pricing Models, a recent post by Phil Kemelor in CMP's Intelligent Enterprise Weblog. Describing how he sees Web Analytics (WA) vendors adapting to Web 2.0, Phil continues ...

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Buying test tools is sometimes just like buying a new car: the salesman tells you that the car is reliable and has a great warranty; then the finance person warns of everything that could go wrong that isn't covered in the warranty and trys to sell you an extended warranty and maintenance contract.

Ben Simo, the author of the first paragraph, writes the blog Quality Frog. He is a software tester and test automation developer. His blog contains his "ramblings about software testing" and links to useful resources. In his post Performance Testing Lessons Learned, Ben shares his experiences with load testing and load testing tools.

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Most bloggers, especially those who work in high tech, want to like Technorati. Its mission (and even its name) appeals to our vanity. When Technorati launched in November 2002, that mission was simple and easy to understand. By tracking links among blogs, and finding the most popular, it would determine which blogs were the most authoritative.

Over the years, that mission expanded from simply tracking the 100 most popular blogs to include periodic reports on the state of the blogosphere.

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