> On Oct 7, 2013, at 11:34, Toni Helenius <Toni.Helenius@xxxxxxxxxxxxxxx> > wrote: > > > Hi, > > > > yes, I'm cheating by using GUI :) (PgAdmin) > > Please do not top-post. > > Analyze is an entirely different command than Explain analyze. Analyze > updates the statistics of tables, while Explain analyze tells how those > statistics affect the query plan. > > > Here: > > > > "Aggregate (cost=18240.50..18240.51 rows=1 width=0) (actual > time=2911.117..2911.119 rows=1 loops=1)" > > " -> Seq Scan on min1_009 (cost=0.00..18108.60 rows=52760 width=0) > (actual time=5.390..2816.274 rows=52760 loops=1)" > > "Total runtime: 2912.211 ms" > > That article you referenced mentions pg_class.relallvisible - what > value does that have for your table? > Is it possible that a relatively large amount of the data in that table > is not visible to other sessions, or was that perhaps the case when you > last (vacuum) analyzed the table? Hmm, yes I didn't check these before. SELECT pg_class.relname, pg_class.relallvisible, pg_class.relpages FROM pg_class where pg_class.relname = 'min1_009'; "min1_009";0;17581 So no pages are visible? How come? They should be? The schema I'm on has GRANT ALL ON SCHEMA "SERIES" TO public; > What is the plan if you set enable_seqscan = off; in your session? Does > that give any more insight? > > > -----Original Message----- > > From: Alban Hertroys [mailto:haramrae@xxxxxxxxx] > > Sent: 7. lokakuuta 2013 12:31 > > To: Toni Helenius > > Cc: pgsql-general@xxxxxxxxxxxxxx > > Subject: Re: Index only select count(*) > > > > On Oct 7, 2013, at 11:23, Toni Helenius > <Toni.Helenius@xxxxxxxxxxxxxxx> wrote: > > > >> The output of analyze: > >> "Aggregate (cost=18240.50..18240.51 rows=1 width=0)" > >> " -> Seq Scan on min1_009 (cost=0.00..18108.60 rows=52760 > width=0)" > > > > That's the output of Explain, not of Explain Analyze. The latter has > actual measurements to go with the estimated costs, which gives a lot > more insight. > > > > Alban Hertroys > > -- > > If you can't see the forest for the trees, cut the trees and you'll > find there is no forest. > > > > Alban Hertroys > -- > If you can't see the forest for the trees, cut the trees and you'll > find there is no forest. -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
