Re: Index usage btree+gist ?

Tom Lane a écrit :
> Arnaud Lesauvage <thewild@freesurf.fr> writes:
>> I have a table with a lot of rows (~3.000.000 I believe), and two
>> indexes.
>> The first one is a BTree index on a column (lets call it
>> btreecolumn) which contains only 8 different integer values (from
>> 0 to 8).
>
> An index as unselective as that is almost useless.  It's not surprising
> that the planner doesn't think it's worth the trouble to use it.

OK, thanks for pointing this out.
I was advised the PostGis list to use a multicolumn index on both
the integer column and the geometry column.
Another suggestion was to cluster the table on the gist-geometry
index.
What do you think about that ?

Regards
--
Arnaud