Re: On-disk bitmap index patch

Gavin Sherry <swm(at)linuxworld(dot)com(dot)au> writes:
> Is anyone else looking at this patch?

It's on my list of things to look at, but so are a lot of other patches ;-)

A couple of comments after a *very* fast scan through the patch:

* The xlog routines need help; they seem to not be updated for recent
changes in the API for xlog recovery code.

* The hacks on vacuum.c (where it tests the AM name) are utterly
unacceptable. If you need the main code to do something special for a
particular index AM, define a bool flag column for it in pg_am.

* The interface to the existing executor bitmap scan code is mighty
messy --- seems like there's a lot of almost duplicate code, a lot
of rather invasive hacking, etc. This needs to be rethought and
refactored.

* Why in the world is it introducing duplicate copies of a lot
of btree comparison functions? Use the ones that are there.

* The patch itself is a mess: it introduces .orig and .rej files,
changes around $PostgreSQL$ lines, etc.

However, the main problem I've got with this is that a new index AM is a
pretty large burden, and no one's made the slightest effort to sell
pghackers on taking this on. What's the use-case, what's the
performance like, where is it really an improvement over what we've got?

regards, tom lane