Re: PATCH: index-only scans with partial indexes

I tried to whip this into shape, but there were a few areas I
didn't feel I had the necessary understanding to feel comfortable
taking on the committer role for it. I've cleaned it up the best I
could, fixing whitespace and typos, eliminating an unnecessary
addition of an include, improving C comments (at least to my eye),
and adding an Assert where it seemed like a good idea to me.

My own tests and those of others show performance improvements (up
to 10x for some tests) and no significant performance degradation,
even with attempts to create "worst case" scenarios.

The only changes to the regression tests are to change an "out"
file to eliminate re-checking the index predicate against the heap
on every matching row, which seems like a good thing.

I'm taking my name off as committer and marking it "Ready for
Committer". If someone else wants to comment on the issues where
Tom and Kyotaro-san still seem unsatisfied to the point where I
can get my head around it, I could maybe take it back on as
committer -- if anyone feels that could be a net win.

--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company