Re: Use of Functional Indexs and Planner estimates

Manfred Koizar <mkoi-pg(at)aon(dot)at> writes:
> So statistics gathering for expressional indexes will be in 7.5, but I
> don't know about the state of the planner ...

Planner support is there too:

2004-02-16 19:52 tgl

* src/: backend/optimizer/path/costsize.c,
backend/optimizer/util/relnode.c, backend/utils/adt/selfuncs.c,
include/optimizer/pathnode.h, include/utils/selfuncs.h: Make use of
statistics on index expressions. There are still some corner cases
that could stand improvement, but it does all the basic stuff. A
byproduct is that the selectivity routines are no longer
constrained to working on simple Vars; we might in future be able
to improve the behavior for subexpressions that don't match
indexes.

I don't recall anymore what "corner cases" I had in mind for future
improvement.

regards, tom lane