+1 for #postgresql help. Recently I had a really weird problem, and after a few hours with forums and manuals I went there to ask for help. They saved me I don't know how many more hours that would almost for sure not found the completely unexpected answer. Thanks!
But more in general, at least in my experience, understanding and optimizing indexes usage is the most important and most difficult task with postgresql, and improving the documentation about this could really help. Usually they work well on their own, but a few times I was really baffled why pg wouldn't use an index which I created to optimize some important and slow query, even if using the index (when I found a way to "convince" pg to do so) cut the execution time by a factor of 100 or even 1000.
The easiest improvement that comes to my mind would be to add to the manual a better and more in-depth explanation about how to optimize index usage; this could include a FAQ where you could also include my edge case. This current page could be a starting point: http://www.postgresql.org/docs/9.3/interactive/indexes-exami...
An even better but much more long term project would be to improve the EXPLAIN ANALYZE commands; specifically it would be great if it could show the different plans considered, making it easy to understand why a specific plan was discarded. Right now, the only way to nudge pg in the right direction is by trial and error. Also making the explain output easier to understand would help, but I guess that's difficult.
Anyway, thanks again for all the effort of the pg contributors!
