Open Radar

 
Summary:
When setting up an NSFetchedResultsController to feed an UITableView with Sections and Section Index Titles for the first time, performFetch: takes a long time.
After Debugging for a while I noticed that there are two SQL Statements executed: one for the objects and another to fetch the section titles. Both Queries together take up to a few seconds (3GS, 1800 entries to be fetched).
As using another thread for performFetch: is not allowed by the documentation the UI will hang while the fetch is running.
That situation is not very pleasant for us developers, especially if a workaround is known and not documented.

Steps to Reproduce:
Build a Core Data dataset with roughly 3200 entries, where 1600 are to be fetched into 26 sections.
Set up a fetched results controller and call performFetch either:
1. without a cache name
2. for the first time with a cache

Expected Results:
A fast fetch which doesn't stutter the UI and doesn't leave the user in a unresponsive UI while fetching.

Actual Results:
The UI is blocked and the User has no feedback on what's happening.

Regression:

Notes:
This Text has been updated to remove information optained under NDA