> -----Original Message----- > From: Dave Dutcher [mailto:dave@xxxxxxxxxxxx] > Sent: Sunday, January 14, 2007 5:12 PM > To: Rolf Østvik (HA/EXA); pgsql-performance@xxxxxxxxxxxxxx > Subject: RE: [PERFORM] Problem with grouping, uses Sort and > GroupAggregate, HashAggregate is better(?) > > > -----Original Message----- > > From: pgsql-performance-owner@xxxxxxxxxxxxxx > > [mailto:pgsql-performance-owner@xxxxxxxxxxxxxx] On Behalf Of > > Rolf Østvik (HA/EXA) > > Have you tried "set enable_sort=off" with 8.1.2? I'm not > sure if that will > change anything because it has to do at least one sort. Its > just a lots > faster to do a hashagg + small sort than one big sort in this > case. (I > wonder if there should be enable_groupagg?) Did you mean enable_sort = 'off' for 8.2.1? I tried to set enable_sort = 'off' for both the 8.1.4 server and the 8.2.1 server. Both servers used the same plan as Run 4 and Run 3 respectively. There were of course some changes in the planner cost for the sort steps, but the execution times was of course the same. Regards Rolf Østvik
