[Chandler-dev] Pre-loading items as a performance optimization

[Morgen Sagen]

I'm looking into improving the performance of going backwards/ 
forwards a week in the calendar view (bug 5651), so first I got some  
profiling numbers under the following circumstances (on my  
dual-1.8MHz G5):

Imported the test 3000 event calendar into Chandler and quit.   
Restarted Chandler and jumped forward a week, which takes 2.0  
seconds.  0.75 seconds is spent generating occurrences; of that 0.75,  
0.54 seconds is taken up by inserting keys into indexes.

Restarted Chandler and repeated jumping between the same weeks as  
before.  This takes 1.0 seconds.  In this case, the occurrence items  
are already generated, and instead we're loading them from the  
repository.  0.3 seconds is spent loading the items.

Repeating the jump again takes 0.6 seconds, which is further proof  
that item loading is taking between 0.3 and 0.4 seconds in this example.

My thought was that if we could generate occurrences and/or load  
relevant items from the next and previous weeks in the background  
(Andi suggested OnIdle), that could save some time when the user  
clicks the week navigation arrows.  Does anyone see any pitfalls in  
this approach?  Is it possible to load items into the main repository  
view from another thread?  Also, I would need some guidance in  
determining exactly which items need to be pre-loaded.

~morgen