"Hell, Robert" <Robert.Hell@xxxxxxxxxxxx> writes: > That's it - I found a more simple statement which has the same problem > (0.02 seconds vs. 6 seconds): This isn't necessarily the very same problem --- what are the plans for your original case with the two different stats settings? > What's the difference between plan calculation for cursors and straight > queries? The planner is set up to favor fast-start plans a little bit when planning a cursor, on the theory that you are probably more interested in getting some of the rows sooner than you are in the total runtime, and that you might not ever intend to fetch all the rows anyway. In the example you give here, it likes the indexscan/unique plan because of the zero startup cost, even though the total cost is (correctly) estimated as much higher. (Looking at this example, I wonder if the fast-start bias isn't a bit too strong...) It's not immediately apparent to me though how that would affect your original query. regards, tom lane -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
