Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h3ncz-0000Nl-TC for pgsql-performance@arkaria.postgresql.org; Tue, 12 Mar 2019 20:03:58 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1h3ncy-0002yH-MO for pgsql-performance@arkaria.postgresql.org; Tue, 12 Mar 2019 20:03:56 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h3ncy-0002yA-Dr for pgsql-performance@lists.postgresql.org; Tue, 12 Mar 2019 20:03:56 +0000 Received: from mout.perfora.net ([74.208.4.197]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1h3ncw-0000A6-3Y for pgsql-performance@lists.postgresql.org; Tue, 12 Mar 2019 20:03:56 +0000 Received: from [192.168.1.101] ([98.169.208.73]) by mrelay.perfora.net (mreueus001 [74.208.5.2]) with ESMTPSA (Nemesis) id 0MacbH-1hJYHl45t3-00K4k8; Tue, 12 Mar 2019 21:03:17 +0100 Message-ID: <5C88107F.7040902@sqlexec.com> Date: Tue, 12 Mar 2019 16:03:11 -0400 From: MichaelDBA User-Agent: Postbox 5.0.25 (Windows/20180328) MIME-Version: 1.0 To: Michael Lewis CC: Laurenz Albe , Daulat Ram , "pgsql-performance@lists.postgresql.org" Subject: Re: Shared_buffers References: <56099ac31c7cc1a4e8a51963e2674e7fe592b86f.camel@cybertec.at> In-Reply-To: Content-Type: multipart/alternative; boundary="------------060304090108060408040102" X-Provags-ID: V03:K1:EDfiiSPxloK1u5NDYByAeR03s5pFxMa+HMYQXvJ4SjFau9KMPcP MfvlUkeGS1Ai1eqsN2vhLutKEx2P9mEFJpUW1sdFWod2XnTPtrVBwBDwdKrEBhD7pi8ER5o ArFqUZlVxAdnYvzdetOruKpkFqQ4AHde37btmbxYDrnY/PKfINw1osIJ5uxSthbrzwlpuAP N9r1UTIBl2f+NsuXtXZdA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1;V03:K0:zE/9GGHkJNE=:9HuEx4LKck5DuEPNy5DNHJ SvvlJgUf93tWKJv2TfniMAPaQhVg0thB8vljHb6h9UO8pcur/Dj8Up4e4T0R8aW2OP+l791PK nKn4b3iAHwP6mLtvrD+pqpW+tC1ca5Irh8VaFq+mA4JFr+XayzdthFtepWlzu7UAX3iNnGRgp M1+c9/N7524vxF1IA9xClyf8J+2IBFSdfu0OMEfLesJ6+d7zYDtKystcU3E6OmUi5yc1mzhBP tj2UsDS+YgossSpyfGSiuNnvJY5VklZedig3fToo2t1gHMiYF8Ia50mIb7mNVC4Y8X5DCHop5 Hx5oztMS2/za48kN8wllU/apSIPquVDdyPw9p9QepKvVmi1iWcyHX9nbvBeJXoauNIMsNNnXG Kz70RtnJCYWLZx36a0w/Wul4TtahLKXJTZ69Rq40pppINdI5hgpkMk6qhlVysqL7hEiod7hLO vDPNtfUDBKFhcEPNqBgCq2UL4rR8GElYOmjjqfVX+uLOp+nHOng8SiQvfIsWsQeVL4YPmfScX Daonyk59BU17K5upRK2Ct+dKy+6FD+161oiHLT3bCTrmkgYor4ukp0Y3o4DegWU6zQXeVjUj8 t+wgbEAoYc4xf9l+Pc1JezOWYJgeSo9dF05cpa+APnTNMzLehn4pN7A/bZR1BTAb1P1oK+aXj jeVKTIVm663Ii1cjjEvqIHUYmMv90jxD3ucRRFKs6bEsxlNomb+O59mflJC06raTIvT04qnao jZEtpFfQbhsPaGWP5djB9JHL2l3vXwgMLE8tHGmyC17y+3diDDUHpspwSDM= List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk This is a multi-part message in MIME format. --------------060304090108060408040102 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Set shared_buffers more accurately by using pg_buffercache extension and the related queries during high load times. Regards, Michael Vitale > Michael Lewis > Tuesday, March 12, 2019 3:23 PM > On Tue, Mar 12, 2019 at 2:29 AM Laurenz Albe > wrote: > > Daulat Ram wrote: > > I want to know about the working and importance of > shared_buffers in Postgresql? > > is it similar to the oracle database buffer cache? > > Yes, exactly. > > The main difference is that PostgreSQL uses buffered I/O, while > Oracle usually > uses direct I/O. > > Usually you start with shared_buffers being the minimum of a > quarter of the > available RAM and 8 GB. > > > Any good rule of thumb or write up about when shared buffers in excess > of 8GBs makes sense (assuming system ram 64+ GBs perhaps)? --------------060304090108060408040102 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 8bit Set shared_buffers more accurately by using pg_buffercache extension and the related queries during high load times.

Regards,
Michael Vitale

Tuesday, March 12, 2019 3:23 PM
On Tue, Mar 12, 2019 at 2:29 AM Laurenz Albe <laurenz.albe@cybertec.at> wrote:
Daulat Ram wrote:
> I want to know about the working and importance of shared_buffers  in Postgresql?
> is it similar to the oracle database buffer cache?

Yes, exactly.

The main difference is that PostgreSQL uses buffered I/O, while Oracle usually
uses direct I/O.

Usually you start with shared_buffers being the minimum of a quarter of the
available RAM and 8 GB.

Any good rule of thumb or write up about when shared buffers in excess of 8GBs makes sense (assuming system ram 64+ GBs perhaps)?

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