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 1tOJ5r-005U8V-K4 for pgsql-hackers@arkaria.postgresql.org; Thu, 19 Dec 2024 16:09:43 +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 1tOJ5q-00EmRT-SG for pgsql-hackers@arkaria.postgresql.org; Thu, 19 Dec 2024 16:09:42 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1tOJ5q-00EmRK-IO for pgsql-hackers@lists.postgresql.org; Thu, 19 Dec 2024 16:09:42 +0000 Received: from mail-io1-xd31.google.com ([2607:f8b0:4864:20::d31]) by magus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1tOJ5n-000bs3-6L for pgsql-hackers@postgresql.org; Thu, 19 Dec 2024 16:09:41 +0000 Received: by mail-io1-xd31.google.com with SMTP id ca18e2360f4ac-844bff5ba1dso70215639f.1 for ; Thu, 19 Dec 2024 08:09:39 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1734624578; x=1735229378; darn=postgresql.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=NAvTcCnnkDIhETkK+v9UdistanB7Qk1QUdz89Fkdshg=; b=JA8p68g+HsCeZLtnlwVc9let/w2DxHS+jfiBGW1Dbnf3bvTu8X5jA+W6RXbtruEtE9 CeL8nyme7enqfivSVkY7Ac2ZFbtkEklOiFL6XU/WfcAj2mvxot8lVC0CvEGQsZSRTfbW PFyvFUcS/ZPT1YW6hSWiy+qFOGoGqNZVudSDiH9g13gU4Dwcj+rtRpcfvmYWdVHw6XnU rILTFwT3NIv0eqO7ES+wRoWDQ4yytKtLvuQyjHAJlSGjSRbiSUBkEcz8T0B9yXzVmcFY M+zilEfHhCVBtxHtluzyfJijvmMhM7KAWVrUpbXa5Bv+O50YN9hqzHWu5dcKbdinud6h I8JQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1734624578; x=1735229378; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=NAvTcCnnkDIhETkK+v9UdistanB7Qk1QUdz89Fkdshg=; b=wu6ZIQOomZX+2Ud8xGeU3oBA0oF71VmCVfEIAstKpeANt67kWr5/NY/ogN3eY4qq48 KBXxTRq/skKS5k3Lf8V4z8Z/cBS+ipMfhWRYhurJ/qjsExJRvnk61bY24D5arv++5ncP 4PeeOVb2yFioGD9/C6Uhg2c748D5w4OirVaWZkGEVW7Gs6F7b4IFX7Qfp0+iW1PfgHDJ zguXKXlCp3RvDaCVQs1aeXw9QhqoKB63CQ74rYLvk3oZdAYNHnhVh8RUBdKQ5iCK4GMi T+9RrGqzeAXTrt4ZRASoRROaT8w/isrTo7aV9HOKBUScooZKKmjxWqOSy7wXODurTNvk T2JQ== X-Gm-Message-State: AOJu0Ywv+FR/vOX4GmILe8+JJvpu8wVRoZqYnLNEEoTMeH63OHPI8jWw pmqbKjtBrpL3TLNb4el9PlRJ5z+fJhn9/Ieh/VVj/BD9LLdLw27T X-Gm-Gg: ASbGnct/hXvHnX5tGAXgz7q943+4AG4o7tBD7LsoHfprmitPxnRyU9ryzJFpJFDsc2b La82KaYLtrWXAE1D7qE0pOJlb5Be0et96B8v4D5OClME1sdKFcrdkrVlLXc9BwfSCGQix6Z/K+V 2oMm6d+Qdf7uzBo9oc8qG7G+NkQP+8ahM553dDsmMrwtsUgTTjajK28EZuHz7hZlIWUEr00XM3N TcDhX18SuYKm//Nn3S1YUi32L/Kvk5XHhSjMyfBuB5gplVi2ueK4NpVrhRTDH2akBLlrB3/vTU0 t2gn3PBlIJSLnwrZ2Pd5l+w8baqnhOFHKIAlkbSckfzbAW0= X-Google-Smtp-Source: AGHT+IGYVd0vg7Awi7Y13TrgzgiJ+gSQVixm0HenOhB7t7/J5p3A0NECzNNvHBeT7UThzyndOEBA8A== X-Received: by 2002:a05:6602:15cc:b0:841:a678:de2e with SMTP id ca18e2360f4ac-847584f25cfmr831925339f.2.1734624577700; Thu, 19 Dec 2024 08:09:37 -0800 (PST) Received: from nathan (162-195-168-172.lightspeed.stlsmo.sbcglobal.net. [162.195.168.172]) by smtp.gmail.com with ESMTPSA id ca18e2360f4ac-8498d80dab1sm34347539f.22.2024.12.19.08.09.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Dec 2024 08:09:37 -0800 (PST) Date: Thu, 19 Dec 2024 10:09:35 -0600 From: Nathan Bossart To: Thomas Munro Cc: pgsql-hackers@postgresql.org Subject: Re: connection establishment versus parallel workers Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk Sorry for the delay, and thanks again for digging into this. On Fri, Dec 13, 2024 at 03:56:00PM +1300, Thomas Munro wrote: > 0001 patch is unchanged, 0002 patch sketches out a response to the > observation a couple of paragraphs above. Both of these patches seem to improve matters quite a bit. I haven't yet thought too deeply about it all, but upon a skim, your patches seem entirely reasonable to me. However, while this makes the test numbers for >= v16 look more like those for v15, we're also seeing a big jump from v13 to v14. This bisects pretty cleanly to commit d872510. I haven't figured out _why_ this commit is impacting this particular test, but I figured I'd at least update the thread with what we know so far. -- nathan