Ajax Design Patterns

Chapter 13. Performance Optimization

THE PERFORMANCE OPTIMIZATION PATTERNS IMPROVE THROUGHPUT AS WELL AS APPLY SOME USER-centered techniques to ease the pain of waiting for the server. Browser-Side Cache talks about implementing a custom cache within the application and explains why it’s sometimes more suitable than the standard web browser cache. Predictive Fetch extends the cache concept by proposing that likely actions be anticipated, so that required data is already sitting in the browser by the time it’s required. Another very different way to achieve zero network delay is to simply take a stab at the required value, the idea behind Guesstimate.

Multi-Stage Download proposes parallel or scheduled downloads so as to reduce bottlenecks and grab the most critical details as early as possible.

Fat Client is one of several possible Ajax architectural styles that helps optimize performance by pushing as much logic as possible—and potentially storage—over to the browser side.

Browser-Side Cache

⊙ Auto-Update, Memoise, Memoize, Sync, Synchronise, Sychronize, Real-Time

Figure 13-1. Browser-Side Cache

Developer Story

Devi’s produced a physics simulation and, though it’s functional, she’s disappointed that it keeps pausing to request calculations from the server. To speed it up, she sets up a cache that will retain the calculations locally.

Problem

How can you make the system respond quickly ...