What are your top 3 XPages performance tips for new XPages developers?

Question

What 3 things would you tell developers new to XPages to do to help maximize the performance of their XPages apps?

Answer 1

Since you're asking for only 3, here are the tips I feel make the biggest difference:

1. Determine what your users / customers mean by "performance", and set the page persistence option accordingly. If they mean scalability (max concurrent users), keep pages on disk. If they mean speed, keep pages in memory. If they want an ideal mixture of speed and scalability, keep the current page in memory. This latter option really should be the server default (set in the server's xsp.properties file), overridden only as needed per application.
2. Set value bindings to compute on page load (denoted by a $ in the source XML) wherever possible instead of compute dynamically (denoted by a #). $ bindings are only evaluated once, # bindings are recalculated over and over again, so changing computations that only need to be loaded once per page to $ bindings speed up both initial page load and any events fired against the page once loaded.
3. Minimize the use of SSJS. Wherever possible, use standard EL instead (e.g. ${database.title} instead of ${javascript:return database.getTitle();}). Every SSJS expression must be parsed into an abstract syntax tree to be evaluated, which is incrementally slower than the standard EL resolver.

There are many other ways to maximize performance, of course, but in my opinion these are the easiest ways to gain noticeable improvement.