Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.84_2) (envelope-from ) id 1e2Et1-0007TO-3z for pgsql-performance@arkaria.postgresql.org; Wed, 11 Oct 2017 11:09:15 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.84_2) (envelope-from ) id 1e2Et0-00057x-Mt for pgsql-performance@arkaria.postgresql.org; Wed, 11 Oct 2017 11:09:14 +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_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1e2ErD-0008A6-Oa for pgsql-performance@postgresql.org; Wed, 11 Oct 2017 11:07:23 +0000 Received: from mail-1.server.selfnet.de ([141.70.126.65] helo=mail.wh-stuttgart.net) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1e2ErB-0003l2-7U for pgsql-performance@postgresql.org; Wed, 11 Oct 2017 11:07:23 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.wh-stuttgart.net (Postfix) with ESMTP id 4D7C2184AEB for ; Wed, 11 Oct 2017 13:07:18 +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 fJ9blSnIVew7 for ; Wed, 11 Oct 2017 13:07:18 +0200 (CEST) Received: from mail-oi0-f41.google.com (mail-oi0-f41.google.com [209.85.218.41]) by mail.wh-stuttgart.net (Postfix) with ESMTPSA for ; Wed, 11 Oct 2017 13:07:17 +0200 (CEST) Received: by mail-oi0-f41.google.com with SMTP id f66so2253678oib.2 for ; Wed, 11 Oct 2017 04:07:17 -0700 (PDT) X-Gm-Message-State: AMCzsaVxcR78Du+PQbT/vK50IxSlmvZwWFlprSB9SpDO1KtkGBf3FUtv E70Qdc1vC6dHYhp4ZHJnSofuYLNvhw/HrdA0BlM= X-Google-Smtp-Source: AOwi7QD9+cPJyW47GhjmtP1IFztFYt7MfZ/PHIH3rreFuX9HNtybpotgVAchiLF0fW95uugwQQ0RC1jxr7DTPxRpM1I= X-Received: by 10.157.17.175 with SMTP id v44mr3397984otf.450.1507720036571; Wed, 11 Oct 2017 04:07:16 -0700 (PDT) MIME-Version: 1.0 Received: by 10.58.67.138 with HTTP; Wed, 11 Oct 2017 04:06:46 -0700 (PDT) From: =?UTF-8?Q?johannes_gra=C3=ABn?= Date: Wed, 11 Oct 2017 13:06:46 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: performance drop after upgrade (9.6 > 10) To: 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, I wrote a query that joins several tables usually returning less than 1000 rows, groups them and generates a JSON object of the result. In 9.6 is was a question of milliseconds for that query to return the requested data. Now, after upgrading to 10, the query never returns - at least it hasn't returned in the last hour. To see what happens, I requested the query plan [1]. It looks complex and shows a lot of parallelization. I don't have the query plan from 9.6, but I remember it being considerably simpler. Can anyone have a guess what altered the performance here so dramatically? Is there a way to disable new parallelization features just for this query to see if it makes any difference? Best Johannes [1] https://explain.depesz.com/s/xsPP -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance