Received: from localhost (unknown [200.46.204.183]) by developer.postgresql.org (Postfix) with ESMTP id B36E92E0044 for ; Wed, 30 Apr 2008 12:03:05 -0300 (ADT) Received: from developer.postgresql.org ([200.46.204.71]) by localhost (mx1.hub.org [200.46.204.183]) (amavisd-maia, port 10024) with ESMTP id 79465-01 for ; Wed, 30 Apr 2008 12:02:50 -0300 (ADT) X-Greylist: from auto-whitelisted by SQLgrey-1.7.5 Received: from sss.pgh.pa.us (sss.pgh.pa.us [66.207.139.130]) by developer.postgresql.org (Postfix) with ESMTP id 529DA2E004A for ; Wed, 30 Apr 2008 12:02:49 -0300 (ADT) Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) by sss.pgh.pa.us (8.14.2/8.14.2) with ESMTP id m3UF2dTm018880; Wed, 30 Apr 2008 11:02:39 -0400 (EDT) To: fche@redhat.com (Frank Ch. Eigler) cc: Greg Smith , Gauri Kanekar , pgsql-performance@postgresql.org Subject: Re: Replication Syatem In-reply-to: References: <7e4ba9550804280638ie81dc23w472785c83cd38fcf@mail.gmail.com> <7e4ba9550804280705q43c51e66l104a5ff9272bbd4d@mail.gmail.com> <20080428162243.GN2970@commandprompt.com> <7e4ba9550804282246p73c62fc6y5e7cb7dda55a6b50@mail.gmail.com> <873.1209478562@sss.pgh.pa.us> Comments: In-reply-to fche@redhat.com (Frank Ch. Eigler) message dated "Wed, 30 Apr 2008 10:35:54 -0400" Date: Wed, 30 Apr 2008 11:02:39 -0400 Message-ID: <18879.1209567759@sss.pgh.pa.us> From: Tom Lane X-Virus-Scanned: Maia Mailguard 1.0.1 X-Archive-Number: 200804/468 X-Sequence-Number: 29961 fche@redhat.com (Frank Ch. Eigler) writes: > Tom Lane writes: >> Also, you need to make sure you have the FSM parameters set high enough >> so that all the free space found by a VACUUM run can be remembered. > Would it be difficult to arrange FSM parameters to be automatically > set from the VACUUM reclaim results? Yeah, because the problem is that FSM is kept in shared memory which cannot be resized on-the-fly. In retrospect, trying to keep FSM in shared memory was a spectacularly bad idea (one for which I take full blame). There is work afoot to push it out to disk so that the whole problem goes away; so I don't see much point in worrying about band-aid solutions. regards, tom lane