First version of multi-key index support for GiST

We have implemented multi-key index support for GiST. Patch is available
from http://www.sai.msu.su/~megera/postgres/gist/code/7.1.2/patch_multikeygist.7.1.2.gz
The patch could be applied for postgresql version 7.1.2 and current sources 7.2

1. initdb is required. But, it's possible just to execute update
update pg_am set amstrategies = 12 where amname = 'gist';

2. You have to recompile all gist_*_ops functions

3. multi-key indexes works only for для gist__int_ops and
gist__intbig_ops (from contrib/intarray), because they have
support for NULLs.

As a bonus we fixed several memory leaks in old GiST code.

Example:

create index mgix on tabletest using gist (b gist_int_ops, a
gist__intbig_ops ) with ( islossy );

Regards,
Oleg
_____________________________________________________________
Oleg Bartunov, sci.researcher, hostmaster of AstroNet,
Sternberg Astronomical Institute, Moscow University (Russia)
Internet: oleg(at)sai(dot)msu(dot)su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83