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 1pYoHe-0008Eh-Cg for pgsql-hackers@arkaria.postgresql.org; Sun, 05 Mar 2023 13:20:14 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1pYoGd-0003pK-HW for pgsql-hackers@arkaria.postgresql.org; Sun, 05 Mar 2023 13:19:11 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pYoGd-0003pA-6Q for pgsql-hackers@lists.postgresql.org; Sun, 05 Mar 2023 13:19:11 +0000 Received: from mail-pf1-x441.google.com ([2607:f8b0:4864:20::441]) by magus.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1pYoGW-00048B-UG for pgsql-hackers@lists.postgresql.org; Sun, 05 Mar 2023 13:19:10 +0000 Received: by mail-pf1-x441.google.com with SMTP id b20so4123346pfo.6 for ; Sun, 05 Mar 2023 05:19:04 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678022342; h=message-id:mime-version:subject:to:from:date:from:to:cc:subject :date:message-id:reply-to; bh=UnTiF3lu8WIlO+rNdgfzy1VqTL4X6zq/ZOB+ed6Q0CA=; b=mGDhrCOkOwyQlbUFWJ/1oVi8oTZ0jD+rawkWAD/64PoPbZbaEsQTz/VsxFVUUZRCBu NrmcDvymclr/J6fkfCcDO8YIdVsy4Y+nr8BHHwLMsoluup3pVyOvCo8L+LZV+6FYz93m Du2vqIyZVbgT3mDk7SDbMUDwFaX8bkzL26A8F8sT837+MbDPRGMV55zfQ3xtuQGlPf12 7jlRuQcT6zhe1uVPL9kKy3vKymn5u7Z1cK7hfejKil5bZCYZq1TAy5JCaVnUICNdphUK jTl//K+GSF5M9k2XlzP64YWAzpFmyeMEN1n3A+xXUy6Cz3MUCQuSiRD8s6MlC8snH6Ww w6cA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678022342; h=message-id:mime-version:subject:to:from:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=UnTiF3lu8WIlO+rNdgfzy1VqTL4X6zq/ZOB+ed6Q0CA=; b=TUlGEct+83Xg3bGtxWRNI2jEV9+ZIlWA7oqwBrqVZd2qg5CiZrv4dG0cgDY7s4Fn5j uGJsHZEkfVqkTm1d00Jl+OItyiyLaabPjSjvqZ57c3xLpcoHrR6B0R+xLTafeKcXP3sl e0VGR42JGd1uAuJpnvSkzOnPki72dwCA4q+waR1R3qaqU+sWzufNjtRBNLJybB2bq79y tsEEg1d91lv4NDvEhN8M6aWUZzrrIIBNNFxKDPxyry6WTv92UTm4aHFstFiOc5H8eCDB WbREY9GncGxf9ILS4KlL/St5CiyHZ65srn4pqa5o3SQ5ZFqUvEIcafWnQFgup8oo4irs M7og== X-Gm-Message-State: AO0yUKXUveBopYniAX0Q3nwt5KhK/zf3udDKulQ7scN58uoiDDot90tN OWGakugBDtXKEfYgFYnc1SfsQJ8tlFwb2fc52uI= X-Google-Smtp-Source: AK7set+uoT7vOsFVMKCHBgPSSJcOrwwtQB/RUc/jI1jRfvCqNS1RH1Ua83mkzhrzPWo/8hsBjUhzFw== X-Received: by 2002:a05:6a00:d74:b0:606:d3d1:4cc4 with SMTP id n52-20020a056a000d7400b00606d3d14cc4mr7534215pfv.3.1678022342306; Sun, 05 Mar 2023 05:19:02 -0800 (PST) Received: from LAPTOP-6BJT67H1 ([2406:da14:d33:9f00:63e9:c31e:5632:2733]) by smtp.gmail.com with ESMTPSA id c1-20020a63d141000000b004dff15fc121sm4508083pgj.36.2023.03.05.05.19.01 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 05 Mar 2023 05:19:02 -0800 (PST) Date: Sun, 5 Mar 2023 21:19:02 +0800 From: "jacktby@gmail.com" To: pgsql-hackers Subject: How does pg implement the visiblity of one tuple for specified transaction? X-Priority: 3 X-GUID: 242B6849-5D1B-4839-B09E-665AA64C150E X-Has-Attach: no X-Mailer: Foxmail 7.2.25.213[cn] Mime-Version: 1.0 Message-ID: <202303052105574472012@gmail.com> Content-Type: multipart/alternative; boundary="----=_001_NextPart488628120037_=----" List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk This is a multi-part message in MIME format. ------=_001_NextPart488628120037_=---- Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: base64 DQpTdXBwb3NlIHRoZXJlIGlzIGEgdHJhbnNhY3Rpb24gcnVubmluZywgaG93IGl0IGtub3dzIHRo ZSB0dXBsZXMgdGhhdCBhcmUNCnZpc2libGUgZm9yIGl0Pw0KDQoNCmphY2t0YnlAZ21haWwuY29t DQo= ------=_001_NextPart488628120037_=---- Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable =0A

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Suppose there is a transaction running, how it knows the tuples= that are
visible for it?

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jacktby@gma= il.com
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