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 1sGdot-00FQ5p-Bi for pgsql-general@arkaria.postgresql.org; Mon, 10 Jun 2024 12:08:16 +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 1sGdnt-00BKjE-BR for pgsql-general@arkaria.postgresql.org; Mon, 10 Jun 2024 12:07:14 +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 1sGdns-00BKj6-Us for pgsql-general@lists.postgresql.org; Mon, 10 Jun 2024 12:07:13 +0000 Received: from mail-lf1-x12d.google.com ([2a00:1450:4864:20::12d]) by magus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1sGdnr-000vec-EG for pgsql-general@lists.postgresql.org; Mon, 10 Jun 2024 12:07:13 +0000 Received: by mail-lf1-x12d.google.com with SMTP id 2adb3069b0e04-52bbdb15dd5so3251025e87.3 for ; Mon, 10 Jun 2024 05:07:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1718021230; x=1718626030; darn=lists.postgresql.org; h=to:subject:message-id:date:from:mime-version:from:to:cc:subject :date:message-id:reply-to; bh=hKTwOZZN4mSaTlmc0NPtRQVjuCn4KJj2D9YsPyru044=; b=mAaBuwKBYLjmDN2HIWz2gfNRpPr3GbMSbm4hggOv4EPbfNRR8x0hf1ti+Xo/wP+rkO taIHtULVXFxCAZ6N0gWRFuwktb4S6qUU7w429yL4aBdHM7ZQZX5CT03b/6rZERX6oEo9 MQ8N0e0jabVaYsw2Z3Mnb3m4YIe2ITtijycMaGr7MgGxrbjZBX7tClr2omPC1xyOy/+E anZIUW/SUXUK8XkKSNFULWUVIoD9UXUv415xzwlzw4sOY9V+yz8eSXR8r8AWQoK5j0B2 DWlwbtXQwASt5IDxyjXTFcG8AzhuZZ9BomhvJuuHy+VOEuGcSlww9RGiFGWXOg3ooNXD VeIg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1718021230; x=1718626030; h=to:subject:message-id:date:from:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=hKTwOZZN4mSaTlmc0NPtRQVjuCn4KJj2D9YsPyru044=; b=ubp4wFJw5YQ88dNg3UHsQ3ghwHHRoFqR8o369NTiSrhijpycDPfNyMChm60AQifbqb u45GBWe0fGTlwbtHytQx3foxBwzq0vwv8Vzfu4O9OQcDFtmwSQJRFuV4c0iEbW/LRdgH uQccUna/TJcMSPLm8UMHYsf8TY2CZ0AELiMzIjdoEj3B7lMOfIGJy69JXsNe37Mj4DeT wlG9BX4Nx/vwCPPiKHqQRdLVoJlQq37PKbglyOVhRAq4Yf3OzK12e0FZiN1WU4ra1of3 hsBkvCJ4cEKcorVKEBOlm7r/dhRPlRhsRHO7nyc+dHRqClJmr0qWOwpk10VpD421gc+v Q59Q== X-Gm-Message-State: AOJu0YyEzseOtXmLbrlnWGXwNrUmSPbAkgaxrJVvs59wrlonYADSzZjC Q3WPzgRo+fZbnJ35kEtTTPjQxDBcblDYGNj7v1Gaa66cGhZjOT3AbdF+zyh7x/4uZ7bOgWU4XnE wS+agtimybju2WoaelXRxJntjk6SMBIY= X-Google-Smtp-Source: AGHT+IExgBAkW2UoLfnTFiiuEhIlKifsdqUOHavEDUNnD/j0IduLOWodTFZahqUPthzq8jbPV+qiJ1P3dFJymDwqp4g= X-Received: by 2002:a05:6512:3d87:b0:52c:8c25:4b39 with SMTP id 2adb3069b0e04-52c8c254c7cmr1361078e87.59.1718021229866; Mon, 10 Jun 2024 05:07:09 -0700 (PDT) MIME-Version: 1.0 From: =?UTF-8?Q?Torsten_F=C3=B6rtsch?= Date: Mon, 10 Jun 2024 14:06:58 +0200 Message-ID: Subject: Vacuum backend with backend_xmin? To: pgsql-general Content-Type: multipart/alternative; boundary="0000000000001f783c061a87fde6" List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk --0000000000001f783c061a87fde6 Content-Type: text/plain; charset="UTF-8" Hi, This is a VACUUM FREEZE process. -[ RECORD 1 ]------+-------------- pid | 129471 datid | 16401 datname | feed relid | 1889166 phase | scanning heap heap_blks_total | 1254901 heap_blks_scanned | 1017524 heap_blks_vacuumed | 0 index_vacuum_count | 0 max_dead_tuples | 11184809 num_dead_tuples | 0 backend_xid | backend_xmin | 3267908740 age | 8572 The query is: select v.*, a.backend_xid, a.backend_xmin, age(a.backend_xmin) from pg_stat_progress_vacuum as v join pg_stat_activity as a on a.pid=v.pid Now, my question is why does a vacuum backend have a backend_xmin? I am just curious. Thanks, Torsten --0000000000001f783c061a87fde6 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi,

This is a VACUUM FREEZE process.

-[ RECORD 1 ]------+--------------
pid =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0| 129471
datid =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0| 16401
datname =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0| feed
relid =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0| 1889166
phase =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0=C2=A0=C2=A0| scanning heap
heap_blks_total =C2=A0=C2=A0=C2=A0| 1254901
heap_blks_scanned =C2=A0| 1017524
heap_blks_vacuumed | 0
index_vacuum_count | 0
max_dead_tuples =C2=A0=C2=A0=C2=A0| 11184809
num_dead_tuples =C2=A0=C2=A0=C2=A0| 0
backend_xid =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0| <NULL>
backend_xmin =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0| 3267908740
age =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A0=C2=A0| 8572

The query is:

select v.*, a.backend_xid, a.backend_xmin, age(a.backend_= xmin)
from pg_stat_progress_vacuum as v join pg_stat_ac= tivity as a on a.pid=3Dv.pid

Now, my question is why does a vacuum backend have a backend_xmin? I am = just curious.

Thanks,
Torsten
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