Received: from makus.postgresql.org (makus.postgresql.org [98.129.198.125]) by mail.postgresql.org (Postfix) with ESMTP id 275271259185 for ; Fri, 27 Jan 2012 05:46:19 -0400 (AST) Received: from elizabeth.gransy.com ([89.187.132.199]) by makus.postgresql.org with esmtp (Exim 4.72) (envelope-from ) id 1RqiNu-0004Sl-6T for pgsql-performance@postgresql.org; Fri, 27 Jan 2012 09:46:19 +0000 Received: from sq.gransy.com (localhost [127.0.0.1]) by elizabeth.gransy.com (Postfix) with ESMTP id D751B15E4119; Fri, 27 Jan 2012 10:46:03 +0100 (CET) Received: from 85.163.76.202 (SquirrelMail authenticated user tv@fuzzy.cz) by sq.gransy.com with HTTP; Fri, 27 Jan 2012 10:46:03 +0100 Message-ID: <31f8d7cae7e7e0044e368d1cec6e7077.squirrel@sq.gransy.com> In-Reply-To: References: Date: Fri, 27 Jan 2012 10:46:03 +0100 Subject: Re: PostgreSQL Parallel Processing ! From: "Tomas Vondra" To: "Marti Raudsepp" Cc: "sridhar bamandlapally" , "pgsql-performance" User-Agent: SquirrelMail/1.4.21 MIME-Version: 1.0 Content-Type: text/plain;charset=utf-8 X-Priority: 3 (Normal) Importance: Normal Content-Transfer-Encoding: quoted-printable X-Pg-Spam-Score: -1.9 (-) X-Archive-Number: 201201/82 X-Sequence-Number: 46094 On 27 Leden 2012, 10:06, Marti Raudsepp wrote: > On Fri, Jan 27, 2012 at 06:31, sridhar bamandlapally > wrote: >> ----------------------------------------------------------------------= ---- >> | Id=C2=A0 | Operation=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= | Name | Rows=C2=A0 | Bytes | Cost (%CPU)| Time=C2=A0=C2=A0=C2=A0=C2=A0 >> | >> ----------------------------------------------------------------------= ---- >> |=C2=A0=C2=A0 0 | SELECT STATEMENT=C2=A0 |=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= |=C2=A0 7444K|=C2=A0=C2=A0 944M| 16077=C2=A0=C2=A0 (4)| 00:03:13 >> | >> |=C2=A0=C2=A0 1 |=C2=A0 TABLE ACCESS FULL| EMP=C2=A0 |=C2=A0 7444K|=C2= =A0=C2=A0 944M| 16077=C2=A0=C2=A0 (4)| 00:03:13 >> | >> ----------------------------------------------------------------------= ---- > > Sorry to take this off topic, but... Seriously, over 3 minutes to read > 944 MB of data? That's less than 5 MB/s, what's wrong with your > database? :) Yes, those results are quite suspicious. There's probably something interfering with the queries (other queries, different processes, block cleanout, ...) or maybe this is purely due to caching. sridhar, run the queries repeatedly and my quess is the difference will disappear (and the fist query will be a bit faster I guess). Tomas