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 4.96) (envelope-from ) id 1wUK0g-00154e-28 for pgsql-hackers@arkaria.postgresql.org; Tue, 02 Jun 2026 07:58:02 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.96) (envelope-from ) id 1wUK0f-00DTvx-1p for pgsql-hackers@arkaria.postgresql.org; Tue, 02 Jun 2026 07:58:01 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1wUK0f-00DTvp-0R for pgsql-hackers@lists.postgresql.org; Tue, 02 Jun 2026 07:58:01 +0000 Received: from mail-pl1-x636.google.com ([2607:f8b0:4864:20::636]) by makus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.98.2) (envelope-from ) id 1wUK0d-00000000iAy-29aS for pgsql-hackers@lists.postgresql.org; Tue, 02 Jun 2026 07:58:00 +0000 Received: by mail-pl1-x636.google.com with SMTP id d9443c01a7336-2bf2e8ccca1so22020325ad.0 for ; Tue, 02 Jun 2026 00:57:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1780387078; x=1780991878; darn=lists.postgresql.org; h=content-transfer-encoding:mime-version:user-agent:references :in-reply-to:from:subject:cc:to:message-id:date:from:to:cc:subject :date:message-id:reply-to; bh=tqjEShV9O8mCaclgzO/ApZ/CHfRfgA4VxHCRxLvxGTU=; b=CJVy1mTUBtrAlntvJ/lZIf3QDveJ2AlTWlj1QLpUWSYR/oc66RepFHWfikDG1+yaXM P1IqsjvH5Y7/J9Tx/k81/N5+OMHQrzJ4Bmddu5NupCd3winC38C4aaDPbQtFH3CfMK/d iE4qRJOZIQ0vQPqG6ggRtazzUblRd9KWRKVDSydiskwloREdAipNUrs5dq5JBEY2InaH IxRii9qMopLhXB46TcRc0doUsYcEfOrNLcPZst1upbNxU5NAwW0LkT3iUL4vvEd6MwYo Fxlt3Ky4BAMC12l81ASuWeczyrfOrwuLHNe0ioYUrT888I7YJGV907/92MFpAaa7KG9U yKjA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1780387078; x=1780991878; h=content-transfer-encoding:mime-version:user-agent:references :in-reply-to:from:subject:cc:to:message-id:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=tqjEShV9O8mCaclgzO/ApZ/CHfRfgA4VxHCRxLvxGTU=; b=l/VZdzu1INDYH6UQetJfyJgxyiYdFavY8LUp3PdIf5CKhUtvaiptzW1yh/osfq6T8h Gmb1u/OWxhEUOd8CxuRF9Y8I/68MOnvlJxf0TXlAN3k1z+eFBRgl9nIEJJwSidJGPyX2 dL2opXSE/IdsQdet0t6OW/PR7nZ+eLqmuYmEWbvn/2LDKPMctxRvdwCFfTXEPu2yzo0W V45eFg6GVDf1wAnt4SBwuWpJ6UlCoVv7mG7NCpy48J7UjUa3jUxonxAhhAnMKPQhta1W cSrlj1XaaH/keZloX8j+slgmTv5Lzirvh5ENQp4s7qtUiuImS2hDCi1ut8hFELUwZqY4 mjgg== X-Forwarded-Encrypted: i=1; AFNElJ+c+/+SfB+iJo9me7JQ2oZk2uvK46TUiLAs8jexB+3eEYsHtmG0vOX9RJznHNle1ChqHbsIiMdVrTlNv0Vn@lists.postgresql.org X-Gm-Message-State: AOJu0YznQr7yqjD5ggTHPRc0n5ILhp+HvwrguoJu+BwgCgy4qju9Yzma lJsu430mukcf5Mb9PY0K1cWcgA7WKvBq4PRtiolMl9cVKjVBwCiSxQ4O X-Gm-Gg: Acq92OHN+b+7czkz6guILGCC2tVoBFy9AYZomTABKIPOTMFaVYOBQkuuhOW6/mjbpbn QIN9oZP59iye9pvbanPtdHXfESAVYOCV4dksm6VlSKJ0uLCX4qtZPVlRnn1qnLyba47E58koDRe JpTwmcHpqWNW8XVy0SoPbazFW12xGmFT3X1I0He8FjLIhQVB+ZqOmmRlI1ekLQAqwz9hKGWzlyg 79NllVLnvZjRZMDuva+hCJEmBuNOJnOkBFYaJiY86BiHMDrV24oUI/myg1TlU0yqLNLjqeBuJNW l04eSxK7yiZL1/mbXJFjvisRcninXwUOmpXITRZwIzsq/dmFROI0cQLgsPlM3GPsfgkz0TJCRP5 6L+87Vlqnt8Amw8yD3nB34i9Ts3iZqTrId/8+wWYI9iwtGAhUWLb+k1nqgx53U/CdYw/6AtA5sA /JNuXg2PCqBJz6aaIv5eP8G44oC4PGp3J5rxap2gr0qb/i9rt9/RCPTrjGAfpY04MOR7MMLKwu1 gpnizOrFg== X-Received: by 2002:a17:902:e742:b0:2c0:bf68:b1e9 with SMTP id d9443c01a7336-2c0bf690765mr112520765ad.20.1780387078146; Tue, 02 Jun 2026 00:57:58 -0700 (PDT) Received: from localhost (KD036014041111.ppp-bb.dion.ne.jp. [36.14.41.111]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2bf239e5d83sm133689025ad.8.2026.06.02.00.57.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Jun 2026 00:57:57 -0700 (PDT) Date: Tue, 02 Jun 2026 16:57:55 +0900 (JST) Message-Id: <20260602.165755.1084850050958933598.horikyota.ntt@gmail.com> To: shinya11.kato@gmail.com Cc: scott@scottray.io, laurenz.albe@cybertec.at, japinli@hotmail.com, qiuwenhuifx@gmail.com, samimseih@gmail.com, pgsql-hackers@lists.postgresql.org Subject: Re: Report oldest xmin source when autovacuum cannot remove tuples From: Kyotaro Horiguchi In-Reply-To: References: <6634e1b0b5b74e5c2e3b06201120a81e11d82a55.camel@cybertec.at> <3bnBUxwx2npXqvHL0trI11LOOvzQ7LI0GzWqbaj5SJnk7DTb1uzStGveKwj0JJmBW4ebzGIF3az7of4I4rQeaO_PRqDnnClCduPyjM6gPgM=@scottray.io> User-Agent: Mew version 6.8 on Emacs 29.4 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk Hello. This may be just my personal preference, but I'd rather see information about xid horizon retention exposed through a SQL-visible interface than added to the VACUUM log. VACUUM VERBOSE already reports the removable cutoff and how old it was when the operation ended. That seems sufficient as a signal that the xid horizon is being held back. What I would want to investigate after seeing such a signal is not necessarily what happened to be blocking that particular VACUUM operation at some earlier point, but what is holding the xid horizon back now. For that purpose, a view exposing the current xid/xmin holders seems more useful and less misleading than adding a best-effort blocker guess to the VACUUM log. Also, VACUUM output has traditionally reported facts observed during the operation. Since the blocker information is reconstructed afterwards and is explicitly best-effort, it feels somewhat different in nature from the rest of the information reported there. Regards, -- Kyotaro Horiguchi NTT Open Source Software Center