Find uses/rename is being painfully slow

[Dmitry Risenberg]

I've tried adding the document for parsing twice - simple parsing with
normal priority and full parsing with low priority. This way renaming
speeds up a lot.

However, there is still a problem - some of the files are reparsed too
often (on every startup, even if they are not changed), and this kills
most of the gained benefits. I'm trying to debug this issue, but it is
complicated, because there are no unit tests for background parsing
and duchain. Looks like the call for 'featuresSatisfied' on
preprocessjob.cpp:199 is failing, but I can't track why.

So the question is - how can I debug duchain-related code and see what
is stored in duchain - which file, with what features, when it was
parsed, etc.? And is there any special way to debug updating-related
issues?

-- 
Dmitry Risenberg