It is easy for a measurement tool to sit on a server and measure all requests for service—and this kind of measurement has its uses, especially when load testing or investigating bottlenecks. But because of the variety of implementation possibilities, a common problem when measuring RIAs is that related requests may appear to originate from separate units of work on the client.
Correlating seemingly separate measurements with a particular application activity, task, or phase is tricky. The more complex the client/server relationship, especially when it involves concurrent interactions, the harder it becomes for measurement and analysis tools to perform that correlation properly.
Having more design and implementation options also creates new opportunities for developers to make performance-related mistakes. Accidentally or deliberately, developers can implement “chatty” client/server communication styles that perform extremely slowly under some workload conditions. Even with thorough testing, some of these problems may remain undiscovered until after the application is deployed unless applications are subjected to a systematic SLM process that includes measurement
activities to identify, investigate, and fix them.
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