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
supportfor 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@sai.msu.su, http://www.sai.msu.su/~megera/
phone: +007(095)939-16-83, +007(095)939-23-83