Re: Costly "Sort Key" on indexed timestamp column

<ogjunk-pgjedan@yahoo.com> writes:
> I'm tuning my PostgreSQL DB (7.3.4) and have come across a query that
> doesn't use an index I created specially for it, and consequently takes
> circa 2 seconds to run. :(
> ...
> The output of EXPLAIN ANALYZE follows.  Note how 99% of the total cost
> comes from "Sort Key: userinfo1_.create_date".

No, you are misreading the output.  99% of the cost comes from the join
steps.

I think the problem is that you have forced a not-very-appropriate join
order by use of INNER JOIN syntax, and so the plan is creating
intermediate join outputs that are larger than they need be.  See
http://www.postgresql.org/docs/7.3/static/explicit-joins.html

7.4 is a bit more forgiving about this; compare
http://www.postgresql.org/docs/7.4/static/explicit-joins.html

            regards, tom lane