X-Original-To: pgsql-performance-postgresql.org@localhost.postgresql.org Received: from localhost (av.hub.org [200.46.204.144]) by postgresql.org (Postfix) with ESMTP id EF3569DCBEC for ; Tue, 6 Dec 2005 17:25:05 -0400 (AST) Received: from postgresql.org ([200.46.204.71]) by localhost (av.hub.org [200.46.204.144]) (amavisd-new, port 10024) with ESMTP id 96195-03 for ; Tue, 6 Dec 2005 17:25:01 -0400 (AST) X-Greylist: from auto-whitelisted by SQLgrey- Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by postgresql.org (Postfix) with ESMTP id BE30B9DCAA8 for ; Tue, 6 Dec 2005 17:24:57 -0400 (AST) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.13.1/8.13.1) with ESMTP id jB6LOxcr016503; Tue, 6 Dec 2005 16:24:59 -0500 (EST) To: Ron Mayer cc: pgsql-performance@postgresql.org Subject: Re: Missed index opportunity for outer join? In-reply-to: <4395FF61.6060301@cheapcomplexdevices.com> References: <3267.1133822299@sss.pgh.pa.us> <4678.1133888239@sss.pgh.pa.us> <4395F1F3.1000803@cheapcomplexdevices.com> <15962.1133901211@sss.pgh.pa.us> <4395FF61.6060301@cheapcomplexdevices.com> Comments: In-reply-to Ron Mayer message dated "Tue, 06 Dec 2005 13:15:13 -0800" Date: Tue, 06 Dec 2005 16:24:59 -0500 Message-ID: <16502.1133904299@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: by amavisd-new at hub.org X-Spam-Status: No, score=0.002 required=5 tests=[AWL=0.002] X-Spam-Score: 0.002 X-Spam-Level: X-Archive-Number: 200512/197 X-Sequence-Number: 16018 Ron Mayer writes: > Tom Lane wrote: >> In this explanation, the reason for the change in plans over time could >> be a change in the statistics for the other table. Is "facets" more >> dynamic than "point_features"? > Facets is a big table with rather odd distributions of values. > Many of the values in the indexed columns show up only > once, others show up hundreds-of-thousands of times. Perhaps > an analyze ran and just randomly sampled differently creating > different stats on that table? If you have background tasks doing ANALYZEs then this explanation seems plausible enough. I'm willing to accept it anyway ... regards, tom lane