Received: from malur.postgresql.org ([2a02:16a8:dc51::56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1frrHw-00085H-5h for pgsql-performance@arkaria.postgresql.org; Mon, 20 Aug 2018 21:00:36 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1frrHu-0005lq-NQ for pgsql-performance@arkaria.postgresql.org; Mon, 20 Aug 2018 21:00:34 +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 4.89) (envelope-from ) id 1frrHu-0005lj-8I for pgsql-performance@lists.postgresql.org; Mon, 20 Aug 2018 21:00:34 +0000 Received: from mail-qk0-x243.google.com ([2607:f8b0:400d:c09::243]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1frrHr-0004dd-0X for pgsql-performance@lists.postgresql.org; Mon, 20 Aug 2018 21:00:33 +0000 Received: by mail-qk0-x243.google.com with SMTP id d15-v6so4340841qkc.1 for ; Mon, 20 Aug 2018 14:00:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=2ndquadrant-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :content-transfer-encoding:in-reply-to:user-agent; bh=GpLtzy5i/PI5ytYPC/AKbNYKVXdmXitjL1m+graaREI=; b=bvve3Qp9hnfWbAee8Rb2tgdQtvFl3mWq8KPNRQz3Irc5zoLrgLluvQAxT1qdKzrs8u dS1FMPHvX55dwj9/XuyuxU2OYy7rNFLf/MhNRHlzPWL+0aJUM9Tqe3eWIwkg2ULo5XUz 9TvKoSw7sQ8y8BwJiE/uN2A1Ca3xgnYikQMpO629Et/DeLiiP7PhWznt1zRsdSVLqGT5 /nnkoA42/MSAttglC6JtSlBorBY+NgIuo2s1VDKLUhSmYEc7qVrCux00fBs2edcp129b waAUzaztIUt/cAXSMNVfLbO7vwgbfRVH6TRvLAwhoxauR9yHmPXqnRroTHpD3YhC1tYK Rjeg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=GpLtzy5i/PI5ytYPC/AKbNYKVXdmXitjL1m+graaREI=; b=i+feqN6jrPlmmUOF4k3oLbo6iYtExtp+2rPfQ5WRdkjVAc3aMQMej4USEY+elbk2TX WTrPs4Qj6fAVAmoLGUaya5tjDMISDOHhgWHAIOsp5QB91pgcFP3aGWcBT7QnG9rwm9I6 P5jczsq/mmQWN9lyjc7CUFi+2ld1aSCZDVDBGqKUMp80aQwlf2eK1y1QVsNy0M4qKFsJ mXKaRnq5ABkUSbx29WMs4leo+7UEurMD9/G8rcrxv3XdJh/qVH4VzkOi1ihE/q5QSK6L 3Ighb2STXN0i7sQ7cQ0U8/pl4LeRNSnHTbOMWIJV5rWKC5vZuh5zz3sXc4ZwUFppR8+u 9RHg== X-Gm-Message-State: AOUpUlFJAlWQsIxmPCtlf8rHp9IbtR5JgRyLoWaael7GsjnDUErBjUbX wqWxgZcCwFe9Lk5Yn9hPbWnS+A== X-Google-Smtp-Source: AA+uWPxPwGBXsW8ccbruEOQD7RL5sX3OxjvgpZvaaMQfjHRiBqxu3/MsZfVslGY/QqsGnGznYiyM9g== X-Received: by 2002:a37:6251:: with SMTP id w78-v6mr43654357qkb.364.1534798829964; Mon, 20 Aug 2018 14:00:29 -0700 (PDT) Received: from alvin.alvh.no-ip.org ([190.121.29.3]) by smtp.gmail.com with ESMTPSA id d138-v6sm3134943qke.18.2018.08.20.14.00.29 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 20 Aug 2018 14:00:29 -0700 (PDT) Received: by alvin.alvh.no-ip.org (Postfix, from userid 1000) id 9F7CD66C; Mon, 20 Aug 2018 18:00:27 -0300 (-03) Date: Mon, 20 Aug 2018 18:00:27 -0300 From: Alvaro Herrera To: Fred Habash Cc: pgsql-performance@lists.postgresql.org Subject: Re: Guideline To Resolve LWLock:SubtransControlLock Message-ID: <20180820210027.iu3pryzkfssmptco@alvherre.pgsql> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <82F3FC39-72DA-4C25-804A-212DE0E5ECB3@gmail.com> User-Agent: NeoMutt/20170306-137-4415bd-dirty (1.8.0) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On 2018-Aug-20, Fred Habash wrote: > How do we go about calculating appropriate values for these two parameters ... I don't know a lot about your system, so don't have anything to go on. Also, Aurora is mostly unknown to me. What did Amazon say? > > 'NUM_SUBTRANS_BUFFERS'? > TOTAL_MAX_CACHED_SUBXIDS > > And do both require a recompile? Yes. But maybe they'll just move the contention point a little bit backwards without actually fixing anything. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services