On Tue, 21 Jul 2009, valgog wrote:
There is a problem with GIN and GIST indexes, that they cannot be used by the ORDER BY. Maybe it will be a nice idea to ask Oleg to make it possible to use the b-tree columns in GIST or GIN to make the sort easier, but I have no idea how difficult it will be to implement it in current GIN or GIST structures. I think Oleg or even Tom will be the right people to ask it :)
I can answer that one for GiST, having had a good look at GiST recently. There is simply no useful information about order in a GiST index for it to be used by an ORDER BY. The index structure is just too general, because it needs to cope with the situation where a particular object type does not have a well defined order, or where the "order" is unuseful for indexing.
Matthew -- A good programmer is one who looks both ways before crossing a one-way street. Considering the quality and quantity of one-way streets in Cambridge, it should be no surprise that there are so many good programmers there. -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
