Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e700a-0000zr-MZ for pgsql-performance@arkaria.postgresql.org; Tue, 24 Oct 2017 14:16:44 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1e700a-0006E7-9S for pgsql-performance@arkaria.postgresql.org; Tue, 24 Oct 2017 14:16:44 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1e700Z-0006Du-KF for pgsql-performance@postgresql.org; Tue, 24 Oct 2017 14:16:43 +0000 Received: from mail-1.server.selfnet.de ([141.70.126.65] helo=mail.wh-stuttgart.net) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1e700Q-0008F8-8t for pgsql-performance@postgresql.org; Tue, 24 Oct 2017 14:16:41 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.wh-stuttgart.net (Postfix) with ESMTP id 17B4E184E61 for ; Tue, 24 Oct 2017 16:16:31 +0200 (CEST) X-Virus-Scanned: Debian amavisd-new at mail.selfnet.de Received: from mail.wh-stuttgart.net ([127.0.0.1]) by localhost (mail-1.server.selfnet.de [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id mNjE-8jEvxQT for ; Tue, 24 Oct 2017 16:16:30 +0200 (CEST) Received: from mail-qk0-f181.google.com (mail-qk0-f181.google.com [209.85.220.181]) by mail.wh-stuttgart.net (Postfix) with ESMTPSA for ; Tue, 24 Oct 2017 16:16:30 +0200 (CEST) Received: by mail-qk0-f181.google.com with SMTP id 17so26367555qkq.8 for ; Tue, 24 Oct 2017 07:16:30 -0700 (PDT) X-Gm-Message-State: AMCzsaVmaLmwNdhK6yGU/jpRLW5T9fHUzlCxQRpzjX23uiE7o96Gk01Y SYtgRNNS077mOykixlhUVCE34oIXvfBDM1BWs8g= X-Google-Smtp-Source: ABhQp+Q9cGBRr0aRg0Tk1sbjn/5yzdq0KYri5FEsm/QtY+qReJKquQdtPI39YeIM4zPSlllO+VU06cLjFPLrPUz0dTg= X-Received: by 10.55.215.220 with SMTP id t89mr24731199qkt.34.1508854589626; Tue, 24 Oct 2017 07:16:29 -0700 (PDT) MIME-Version: 1.0 Received: by 10.140.28.34 with HTTP; Tue, 24 Oct 2017 07:15:59 -0700 (PDT) In-Reply-To: References: From: =?UTF-8?Q?johannes_gra=C3=ABn?= Date: Tue, 24 Oct 2017 16:15:59 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: performance drop after upgrade (9.6 > 10) To: Pavel Stehule Cc: "pgsql-performance@postgresql.org" Content-Type: text/plain; charset="UTF-8" List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-performance Precedence: bulk Sender: pgsql-performance-owner@postgresql.org Hi Pavel, *, you were right with ANALYZing the DB first. However, even after doing so, I frequently see Seq Scans where an index was used before. This usually cooccurs with parallelization and looked different before upgrading to 10. I can provide an example for 10 [1], but I cannot generate a query plan for 9.6 anymore. Any ideas what makes the new version more seqscanny? [1] https://explain.depesz.com/s/gXD3 -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance