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 1s1om9-00F99U-CO for pgsql-admin@arkaria.postgresql.org; Tue, 30 Apr 2024 14:48:09 +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 1s1om6-006f6y-Rq for pgsql-admin@arkaria.postgresql.org; Tue, 30 Apr 2024 14:48:07 +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 1s1om5-006f4x-K6 for pgsql-admin@lists.postgresql.org; Tue, 30 Apr 2024 14:48:07 +0000 Received: from mailout.easymail.ca ([64.68.200.34]) by makus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1s1om2-000msF-8i for pgsql-admin@postgresql.org; Tue, 30 Apr 2024 14:48:05 +0000 Received: from localhost (localhost [127.0.0.1]) by mailout.easymail.ca (Postfix) with ESMTP id 4D7AE6E0AB for ; Tue, 30 Apr 2024 14:48:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=elevated-dev.com; s=easymail; t=1714488480; bh=wRtNLF9vZZk3BlG6V8ViIar+GYSo+AlV8V7JSd86kEY=; h=From:Subject:Date:References:To:In-Reply-To:From; b=NpPnfZqjC9oRi1E3n8tmsIsBQ+WGZrXrAkq3UIzXQzV7XSqJ3tjmIMghB55t2a18k bN0UTKX6oSVqMOxzaxgR+fjTmMpiChm/m4knlnADa7xydUuvDYI1zMZBQ5sxHWCgYq Cizw/GeMInQm/lrT3ed4qPwZsB4TgfUQinj1dOMuUptk9SpWMun88Wn6DZa4EUXFZP fE6dk68uI0F8wWlHR1Gx+VCwMEUNISbWm2HexBP/ewIaj0F+OFjc3863loDaa81zOr aA9ZSXjv84oD23MA88QU8esDagt1afydsXTtpFr8ScZCEBFZ7ow/2D8D4ENajDwKuO GG8D//iylWUlQ== X-Virus-Scanned: Debian amavisd-new at emo09-pco.easydns.vpn Received: from mailout.easymail.ca ([127.0.0.1]) by localhost (emo09-pco.easydns.vpn [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id DlpCfDB11UKg for ; Tue, 30 Apr 2024 14:47:59 +0000 (UTC) Received: from smtpclient.apple (unknown [165.140.184.195]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mailout.easymail.ca (Postfix) with ESMTPSA id 49EB46D1FB for ; Tue, 30 Apr 2024 14:47:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=elevated-dev.com; s=easymail; t=1714488479; bh=wRtNLF9vZZk3BlG6V8ViIar+GYSo+AlV8V7JSd86kEY=; h=From:Subject:Date:References:To:In-Reply-To:From; b=kyKn+RRNvtRKAGztvvKGyhkekv7jN4pLdey+IZjNGOz5ImaYqphuPaXQD7yBN2UPu 1wuqkBdHSnHXdV3Z+z1zSbMM5DXQOVlLJ08+naycdNJ7sU4rnj+bzcCyHlQqx4PsDM wSI+Gw7zzsCHx8yEEN/5THuYW8VCV9yrpVK5r3S6SmJufNnDxoeY+/Hh6KNMD/dRHj nhRDZwbX2hi6GoiPwCacyOi2LzW92MMATD1+yp+sKBKYmU/X5U3rS+j7sqDJAIc8n1 7ELux/+u6iubsczlCETgXonDAJxEe6cUkfg5u4AUjH1YmgiSiu5pzJaF8PLALR1vl1 fTN/GKWFI/Jvg== From: Scott Ribe Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3774.500.171.1.1\)) Subject: Re: HA Setup Review Date: Tue, 30 Apr 2024 08:47:48 -0600 References: To: pgsql-admin In-Reply-To: Message-Id: X-Mailer: Apple Mail (2.3774.500.171.1.1) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk > On Apr 30, 2024, at 8:20=E2=80=AFAM, Ron Johnson = wrote: >=20 > ZERO downtime is -- to my knowledge -- impossible with master-slave = replication. There will always be some seconds of lag while the = secondary-that-was is promoted to new-primary, and the applications that = were forcibly disconnected from the old primary are connected to the = new-primary. >=20 > Heck, even in a master-master DB cluster, any connections on the = master that dies will be down until they can connect to the other = master. This is true. However, with a secondary that is up to date, and = applications accessing through pgbouncer, client connections to = pgbouncer are not broken, and pgbouncer connections to postgres can be = reestablished quickly enough that users only observe a slightly slow = response.=