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 1gVlwX-0007sc-FM for pgsql-general@arkaria.postgresql.org; Sat, 08 Dec 2018 23:23:29 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1gVlwW-00047M-42 for pgsql-general@arkaria.postgresql.org; Sat, 08 Dec 2018 23:23:28 +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 1gVlwV-00047B-Pi; Sat, 08 Dec 2018 23:23:27 +0000 Received: from mail-pg1-x529.google.com ([2607:f8b0:4864:20::529]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1gVlwS-0002RJ-Qw; Sat, 08 Dec 2018 23:23:27 +0000 Received: by mail-pg1-x529.google.com with SMTP id v28so3276243pgk.10; Sat, 08 Dec 2018 15:23:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=SApVoj0A1mASQ7ilEqEE0y1AC2Haup92wpFdBicQEes=; b=o5HKUPQfPwompqmjwOwmR1OcCB2bheLtWKchSwTYVBZarEYEVJWzopyyNAbyo7XTYY ZCURLhT+dkRS1zq9XlDhan/vHdrWU9G3l+f2w77lALcPgbb6W06fbzTuN1uRS+t5FqiF RUXgCoiowv7nl9ThpSnANJgaJLmgLKFb9bQpKWuCjc6WytPRzQ1fGFJ9MhNPScHaCcQb yZO4D9y/+wB4QcsV2//S9fmL5EugDuLRRSydwFIp0vpnajhIbE1FbjYg+N7LUkj1UtE8 y7zwL36GaYMk+nuY9HzZOkLbTjAzjihUN6hcA4gsWFWlQws2vL5MmkhEJ1trw10Qjg09 KW8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=SApVoj0A1mASQ7ilEqEE0y1AC2Haup92wpFdBicQEes=; b=XEJat4M+GGogqCs0noBhhBi+Bqsfi0q+HIIOw1NlBTdEFY5+OnK3HLcuRGbWCcqdUq cdDmw7a/ZNCsO1h/g/VmFVsi4dhXfobRm+BSWlF2uHYWdfiiP+StFz2mwOmr2wxQ8sTu uMb+BQLgVxx9XFXoyu/6QtU31qSNMZ9TyoHcRytTIc2LQsr1eJDHmJihJLwXAiE77Jlz wBUGwNmmqg9S/U6BL0y8jsFpbkbR6q40BJfzlVY/d3modTzaOjtwv6sYczm81vR1ml+r sviagSKTJ35CBgrMngA1RtmoKmpvaXVDpzYrsPIaPC/Y6duXGY6nzg5ueHcbF0IoTLrH 85Jw== X-Gm-Message-State: AA+aEWZZwu7qdkPvmP+OkULmZMi0Cy5FlmQ87/umbs0mUI18IBh+HnFh nhuwEaBIaji5uJVCDnBZyhg= X-Google-Smtp-Source: AFSGD/V/0iZ3a/JABXfVL08e70SUtc+RucuGXhgPgRTLhg0y8UVQ0NWgTLPMLUu20HpIacntr+HLrw== X-Received: by 2002:a62:d448:: with SMTP id u8mr7259254pfl.105.1544311401379; Sat, 08 Dec 2018 15:23:21 -0800 (PST) Received: from [192.168.1.71] (d50-92-130-90.bchsia.telus.net. [50.92.130.90]) by smtp.gmail.com with ESMTPSA id w128sm10585129pfw.79.2018.12.08.15.23.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sat, 08 Dec 2018 15:23:20 -0800 (PST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 12.1 \(3445.101.1\)) Subject: Re: amazon aroura config - seriously overcommited defaults? (May be Off Topic) From: Rob Sargent In-Reply-To: <20181208231242.t66zpocct36m4o46@alap3.anarazel.de> Date: Sat, 8 Dec 2018 15:23:19 -0800 Cc: "pgsql-generallists.postgresql.org" , "pgsql-performance@lists.postgresql.org" Content-Transfer-Encoding: quoted-printable Message-Id: <7AF20599-CCD4-43D9-962D-3EB7B3E25122@gmail.com> References: <51a1e143-a679-d525-90a1-3fa8abecaf00@amazon.com> <20181208231242.t66zpocct36m4o46@alap3.anarazel.de> To: Andres Freund X-Mailer: Apple Mail (2.3445.101.1) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk > On Dec 8, 2018, at 3:12 PM, Andres Freund wrote: >=20 > On 2018-12-08 12:06:23 -0800, Jeremy Schneider wrote: >> On RDS PostgreSQL, the default is 25% of your server memory. This = seems >> to be pretty widely accepted as a good starting point on PostgreSQL. >=20 > FWIW, I think it's widely cited, but also bad advice. 25% for a OLTP > workload on a 1TB machine with a database size above 25% is a terrible > idea. >=20 Sorry, could you please expand =E2=80=9Cdatabase size above 25%=E2=80=9D? = 25% of what? rjs