Paul Ramsey <pram...@cleverelephant.ca> writes:
> On Mon, Feb 25, 2019 at 3:01 PM Tom Lane <t...@sss.pgh.pa.us> wrote:
>> It's whichever one the index column's opclass belongs to. Basically what
>> you're trying to do here is verify whether the index will support the
>> optimization you want to perform.
> * If I have tbl1.geom
> * and I have built two indexes on it, a btree_geometry_ops and a
> gist_geometry_ops_2d, and
> * and SupportRequestIndexCondition.opfamily returns me the btree family
> * and I look and see, "damn there is no && operator in there"
> * am I SOL, even though an appropriate index does exist?
No. If there are two indexes matching your function's argument, you'll
get a separate call for each index. The support function is only
responsible for thinking about one index at a time and seeing if it
can be used. If more than one can be used, figuring out which
one is better is done by later cost comparisons.
regards, tom lane
