Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1p7hJM-0007g5-Mc for pgsql-hackers@arkaria.postgresql.org; Tue, 20 Dec 2022 18:25:56 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1p7hJL-00077f-B7 for pgsql-hackers@arkaria.postgresql.org; Tue, 20 Dec 2022 18:25:55 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1p7hJL-00077W-0j for pgsql-hackers@lists.postgresql.org; Tue, 20 Dec 2022 18:25:55 +0000 Received: from mail-lf1-x136.google.com ([2a00:1450:4864:20::136]) by makus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1p7hJI-0005f7-Kb for pgsql-hackers@postgresql.org; Tue, 20 Dec 2022 18:25:54 +0000 Received: by mail-lf1-x136.google.com with SMTP id b3so19929347lfv.2 for ; Tue, 20 Dec 2022 10:25:52 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=1pMOnhVhkOWPzvVFq8lAYfyko34K3xe1H1kJXzPUHa8=; b=iGKT6p8lmJgSLV65hHpa0P1ajxEDDjYdEZV2AqPSsDSZi87PE0yM2QoYyd4b9Fr3kx uRemIU7x7S9hyRfUMj4KQde6kCjr0erxYSzpAmhYeU6eg/+NFRTh2eZbEgO0NcM2XM8V m6uNiQ9xBVDdTFQbxNDs/oU1XFYVqHdfKTW9a0rou7o6rPcfVncdb77KSQBjTCtWl67S ehGBDYWIoXxgAtgVxu+/WMwMxxlI4zhdpJczwbw3/10QxjZ7ggsphbzO/dsMuHrcn3AO uVS6gEEkd55h+X99HuwFg/1EiNh5lGw3o+i9Jn6WBapoqrqLSBxnsRthVgFcB5GVHok0 zHXw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=1pMOnhVhkOWPzvVFq8lAYfyko34K3xe1H1kJXzPUHa8=; b=xPLsEQ7H7UgszJk3Wk2xlZ2aKchUOZzPBTK0cqMR4Ho0+sXF2SJeOCjsqdql4vCzhC t1JZoXUcBjzSsR66FZSdxNKOaG5M55p52kVn9bQham45BAA38b7qoZUcg1KxbH5RB9uQ c5iX7Ts9ViVr4G1YzbYIXGM1ZHod+Psy4B+wDgsMFX54BjvWYQT1TrxK75OyzmU/mfOy LAOLmG5T4uMq3UE99udoGiB8Vu+jQHG+955gjPdcZws3o36UAouo6Aime7QkyMQTRSl3 LQ53YGvkxy5Z8ClnM4hvrzmkjUiafFdqB95d0phGklp5ylH2j+0BUpLCJRiA+QAVhZz9 FgyA== X-Gm-Message-State: ANoB5pnUnnLquT5YW2gGdskEjc9kxxyQsVKhe89fjHNC04vWgf/IePv/ NhvF/0i6GpRXtqplEdu4sFJjw3x6DG+jTaZ1Wik= X-Google-Smtp-Source: AA0mqf4WpDH9eSqa2bSICHaxYQmyFRNm6hcp9ADIK8ejNdJ6XUn+24F0ZlcLTR4wY4Ru/216ZiA3lKUK+cY7nyL9z4Y= X-Received: by 2002:a05:6512:ea8:b0:4b4:f6f4:df2b with SMTP id bi40-20020a0565120ea800b004b4f6f4df2bmr28805197lfb.321.1671560751057; Tue, 20 Dec 2022 10:25:51 -0800 (PST) MIME-Version: 1.0 References: <4b19419f-2e7c-a76b-c948-26d10af6693d@gmail.com> <20221207175824.apmc5clnj2fdjkaq@awork3.anarazel.de> <09c26df0-c5f9-eae0-5a6a-10fb00b0522e@gmail.com> <9f0a021e-40e1-0ae6-8086-a4457c99749e@gmail.com> <0ae83e69-bda0-0eb8-ef4a-d169292e3f66@gmail.com> <47f5faf0-6a6d-602a-5d5b-9449ca74c6ad@gmail.com> <20221214173552.sshklqvwezeo52h3@alap3.anarazel.de> In-Reply-To: From: Robert Haas Date: Tue, 20 Dec 2022 13:25:39 -0500 Message-ID: Subject: Re: Minimal logical decoding on standbys To: Andres Freund Cc: "Drouvot, Bertrand" , Alvaro Herrera , Ibrar Ahmed , Amit Khandekar , fabriziomello@gmail.com, tushar , Rahila Syed , pgsql-hackers Content-Type: text/plain; charset="UTF-8" List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On Wed, Dec 14, 2022 at 12:48 PM Robert Haas wrote: > No? Nope, I was wrong. The block reference data is stored in the WAL record *before* the main data, so it was wrong to imagine (as I did) that the alignment of the main data would affect the alignment of the block data. If anything, it's the other way around. That means that the only records where this patch could conceivably cause a problem are those where something is stored in the main data after the main struct. And there aren't many of those, because an awful lot of record types have moved to using the block data. I'm going to go through all the record types one by one before commenting further. -- Robert Haas EDB: http://www.enterprisedb.com