Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1Uttjg-0005yT-DU for pgsql-hackers@arkaria.postgresql.org; Tue, 02 Jul 2013 06:06:44 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1Uttjf-00016V-Q3 for pgsql-hackers@arkaria.postgresql.org; Tue, 02 Jul 2013 06:06:43 +0000 Received: from makus.postgresql.org ([2001:4800:7903:4::125]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1Uttje-00016P-Vm for pgsql-hackers@postgresql.org; Tue, 02 Jul 2013 06:06:43 +0000 Received: from szxga01-in.huawei.com ([119.145.14.64]) by makus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1Uttjc-0002nl-8W for pgsql-hackers@postgresql.org; Tue, 02 Jul 2013 06:06:42 +0000 Received: from 172.24.2.119 (EHLO szxeml210-edg.china.huawei.com) ([172.24.2.119]) by szxrg01-dlp.huawei.com (MOS 4.3.4-GA FastPath queued) with ESMTP id BEP56526; Tue, 02 Jul 2013 13:56:21 +0800 (CST) Received: from SZXEML408-HUB.china.huawei.com (10.82.67.95) by szxeml210-edg.china.huawei.com (172.24.2.183) with Microsoft SMTP Server (TLS) id 14.1.323.7; Tue, 2 Jul 2013 13:56:19 +0800 Received: from blrprnc09ns (10.18.96.98) by szxeml408-hub.china.huawei.com (10.82.67.95) with Microsoft SMTP Server id 14.1.323.7; Tue, 2 Jul 2013 13:56:14 +0800 From: Amit Kapila To: "'Robert Haas'" CC: "'Andres Freund'" , "'Greg Smith'" , "'PostgreSQL-development'" References: <51928CDA.7030009@2ndQuadrant.com> <5194eb32.85d60e0a.1c17.2253SMTPIN_ADDED_BROKEN@mx.google.com> <519b1d5f.9025b40a.2d07.ffffed08SMTPIN_ADDED_BROKEN@mx.google.com> <519f060c.cade440a.493f.ffffb080SMTPIN_ADDED_BROKEN@mx.google.com> <51b033cf.25dc420a.1edd.ffff8fd9SMTPIN_ADDED_BROKEN@mx.google.com> <51cada34.c31b0f0a.2927.7bfbSMTPIN_ADDED_BROKEN@mx.google.com> <51cd16b6.a2d8420a.2b95.ffffb090SMTPIN_ADDED_BROKEN@mx.google.com> <6C0B27F7206C9E4CA54AE035729E9C38421BBB6C@szxeml558-mbs.china.huawei.com> In-Reply-To: Subject: Re: Move unused buffers to freelist Date: Tue, 2 Jul 2013 11:26:13 +0530 Message-ID: <01d301ce76e8$dcde27c0$969a7740$@kapila@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: Ac52iP/T4jc4Ea3jTQSao+zyDsQ4CQAX1gUA Content-Language: en-us X-Originating-IP: [10.18.96.98] X-CFilter-Loop: Reflected X-Pg-Spam-Score: 1.1 (+) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org On Tuesday, July 02, 2013 12:00 AM Robert Haas wrote: > On Sun, Jun 30, 2013 at 3:24 AM, Amit kapila > wrote: > > Do you think it will be sufficient to just wake bgwriter when the > buffers in freelist drops > > below low watermark, how about it's current job of flushing dirty > buffers? > > Well, the only point of flushing dirty buffers in the background > writer is to make sure that backends can allocate buffers quickly. If > there are clean buffers already in the freelist, that's not a concern. > So... > > > I mean to ask that if for some scenario where there are sufficient > buffers in freelist, but most > > other buffers are dirty, will delaying flush untill number of buffers > fall below low watermark is okay. > > ...I think this is OK, or at least we should assume it's OK until we > have evidence that it isn't. Sure, after completing my other review work of Commit Fest, I will devise the solution for the suggestions summarized in previous mail and then start a discussion about same. With Regards, Amit Kapila. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers