Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ult7s-006sYJ-BV for pgsql-performance@arkaria.postgresql.org; Tue, 12 Aug 2025 17:49:32 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.94.2) (envelope-from ) id 1ult7q-008wM4-LH for pgsql-performance@arkaria.postgresql.org; Tue, 12 Aug 2025 17:49:30 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1ult7q-008wLv-BI for pgsql-performance@lists.postgresql.org; Tue, 12 Aug 2025 17:49:30 +0000 Received: from momjian.us ([72.94.173.45]) by makus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1ult7n-000E55-34 for pgsql-performance@lists.postgresql.org; Tue, 12 Aug 2025 17:49:29 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=momjian.us; s=2025010100; h=In-Reply-To:Content-Transfer-Encoding:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-ID:Content-Description; bh=ug/NwQP+77M2YB4VrckjFWkAI6HH6RqHUKwD8TzR58s=; b=m/JUpfPWGF1QJ8uR43NTJ8ed38 eB4kLuq1bf/Vtnby5No+JcsYIVjiikvMByki8Z6c1yL4l/eOL0x3XdsjpKs5cCiicIxy4T2G0IGbz 8iViBu4vwndY5LpwGU8XtG81d53HP+Y9TsZPT8xNQexQCqH/nMv6DUzjENjhtsZvi6GGBL2wcTsnZ L4gCnt5F7IsqhiowLMbEKnHgXpFE/Ag3zJYnQSOulu1EBhRRZl4q07a2z9sP/F3ejYCfLTlF1YT5K v9NbaIyav/KQkWB7ijQQcO/Wvd97Bu4bRAf8u+/cfutdDMt3dNST/qDLY7myd++7oGROnPI2JceBt caEoII2g==; Received: from bruce by momjian.us with local (Exim 4.96) (envelope-from ) id 1ult7n-00AAiL-01; Tue, 12 Aug 2025 13:49:27 -0400 Date: Tue, 12 Aug 2025 13:49:26 -0400 From: Bruce Momjian To: Frits Hoogland Cc: Joe Conway , Priya V , pgsql-performance@lists.postgresql.org Subject: Re: Safe vm.overcommit_ratio for Large Multi-Instance PostgreSQL Fleet Message-ID: References: <3A250F65-F5DE-4E24-ADE7-BEFF4A18A8B9@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <3A250F65-F5DE-4E24-ADE7-BEFF4A18A8B9@gmail.com> List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On Wed, Aug 6, 2025 at 11:14:34PM +0200, Frits Hoogland wrote: > > As I said, do not disable swap. You don't need a huge amount, but maybe 16 GB or so would do it. > > Joe, please, can you state a technical reason for saying this? > All you are saying is ‘don’t do this’. > > I’ve stated my reasons for why this doesn’t make sense, and you don’t give any reason. > > The article you cite does seem to point to general usage, not database usage. Here is a blog entry about it from 2012: https://momjian.us/main/blogs/pgblog/2012.html#July_25_2012 -- Bruce Momjian https://momjian.us EDB https://enterprisedb.com Do not let urgent matters crowd out time for investment in the future.