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 1wPgOY-000wzT-2L for pgsql-novice@arkaria.postgresql.org; Wed, 20 May 2026 12:51:30 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.96) (envelope-from ) id 1wPgOU-007i6o-2R for pgsql-novice@arkaria.postgresql.org; Wed, 20 May 2026 12:51:27 +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 4.96) (envelope-from ) id 1wPgOU-007i6a-1Y for pgsql-novice@lists.postgresql.org; Wed, 20 May 2026 12:51:27 +0000 Received: from mail-wm1-x32e.google.com ([2a00:1450:4864:20::32e]) by magus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.98.2) (envelope-from ) id 1wPgOT-00000000YGR-06V1 for pgsql-novice@lists.postgresql.org; Wed, 20 May 2026 12:51:26 +0000 Received: by mail-wm1-x32e.google.com with SMTP id 5b1f17b1804b1-48896199cbaso38445015e9.1 for ; Wed, 20 May 2026 05:51:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cybertec.at; s=google; t=1779281482; x=1779886282; darn=lists.postgresql.org; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:to:from:subject:message-id:from:to:cc:subject:date :message-id:reply-to; bh=d2Pidnxa/DgDlvdxf6GmTAjzv6zBOWhsSlC8oRB6IB4=; b=CMDw/3zJTu1CImX+AQdSQl1D7LPdCHOkP5MgWDBXMYI4g4cCAbQVTW76M/GOeahl0N 2KOVMkQ6ocVEHOgBO+PXnUqj9gD3k+cTNyfdkbFLGY99tu6ypzec6YHc1LQz+NUbLGHN 45Z+NY6RP4IM19p64Di1HEAsLpY+AdzMUt2y39/XXO+EdsGIChbT6tDV/YVqqjLjLNah WYfUvX0q+qH9ak+Fz8g/QcBRSDloRT4B49IMAUA8mfXB3QM5ZmGi7udKVBAuLA0SZEDm BMV/p482oFwcNGa22Eq87a6xnQNI4EG8MRlO1B0EOCWKNvea+w3Xf9blJbxdm0MxuLFQ iPyw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1779281482; x=1779886282; h=mime-version:user-agent:content-transfer-encoding:references :in-reply-to:date:to:from:subject:message-id:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=d2Pidnxa/DgDlvdxf6GmTAjzv6zBOWhsSlC8oRB6IB4=; b=Zn62YEEGunvm4qiYgCI7lDSmEbxnOC/45nSmZXITmhNEnCjrkVyFQBUrB2iUaDar/V +MOU3Pv8kWv3AnUk0pAR0CQmJ/2GtOBIJKhH5U4KeBamxS5w8dg7aKSKwfa4D2IfyIXP Pgn1lEPLCtroqt4v1XvdJC2aZ/r8GvoEDeRXby8uoH5W6nwCJuLgTpXtFcdx9vjJDHEs mNBwr9O79ueY0jNGX3+92e5LC1nYSEVJFaTgRkPVVD9tGUyN2QfZCdLTKfwLrBhgyBGC RShkEiuRYSgeIwruQfbIkc1cAWBdjxTewXuiarjq6Kv/YZr6e0igzfeldsDamj1wcO7I ZoCQ== X-Forwarded-Encrypted: i=1; AFNElJ9D75p6zBYaH0fUySmzXBRkR8fchhTd1CJ7onrimVf5nwX8uMXolPeQVHZRRB//H8lrjrKWwgmxk9Y3V5A=@lists.postgresql.org X-Gm-Message-State: AOJu0YzEs+G72ELKPkRN81NY/PkN/bR+idkkiVr8Z90iXZonfiDvEUNE wo6Bh/wMI3US1oNpJUAcd1Z5pY/W3gEmM/gpumeFntB0yajYkPT9iQwukLT0S9zJVDs= X-Gm-Gg: Acq92OE8j04FUtZL6Fo0oWylLvEAgAGdGDpMd0gVX6/7Q9qeEYmuTdwpZVktue+igMS 0eQ/YQIHYed8JeilIzHrZEHigKAKIUj2TWE2azu4ohG9rf+w3coQ6uRbSWfI1vPHriABeC7qx8t W+i22CvTv+1LySlMFUudMPPZrBxzOBZWi+CvkJHRmzaYYwdA9cuAss5ReWoO2UbY2zEhefKFuvF 2qIIkIKHSEuew8/KyouljGRTbPldRgPFb7A7n7lAHl+ersIRmg/guW5n5w3I9gFh/lWmHZis7Be 4cFWT4rBrcJEULauWKA1n6emMaSwjj+plwja8JQ0jQXYwL+7oKT3H+MUvOZZ9WpTNlK2nZ4xey8 zwxyKkbSZpFIn47768GMB9bA5s/j1EKIdKZ8MkH+ntFUdesumNfTAn+VvI/fAzcM1XAwKrPRxQg OGDUMXg4UFRShZBOAbwuUe7GK6eXwEMkHjY4lAllI/PDXyHsm/8eA= X-Received: by 2002:a05:600c:37ca:b0:489:1a63:509c with SMTP id 5b1f17b1804b1-48fe59b05b2mr379091525e9.0.1779281481709; Wed, 20 May 2026 05:51:21 -0700 (PDT) Received: from laurenz.albe-K4N0CV00F97414D ([24.109.50.222]) by smtp.gmail.com with ESMTPSA id 41be03b00d2f7-c82bb07b007sm19740406a12.11.2026.05.20.05.51.20 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 20 May 2026 05:51:20 -0700 (PDT) Message-ID: <2e0b32980172f955362b7392a3a8949f86471ac5.camel@cybertec.at> Subject: Re: Why only some files have fsm and vm extensions From: Laurenz Albe To: "Subramanian,Ramachandran" , "pgsql-novice@lists.postgresql.org" Date: Wed, 20 May 2026 05:51:19 -0700 In-Reply-To: <6ad2ace1ccaa48c3a7fe41f785c359b3@alte-leipziger.de> References: <6ad2ace1ccaa48c3a7fe41f785c359b3@alte-leipziger.de> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.58.3 (3.58.3-1.fc43) MIME-Version: 1.0 List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk On Wed, 2026-05-20 at 09:48 +0000, Subramanian,Ramachandran wrote: > I am beginning to read the internals of Postgres , got curious and looked= at the actual files . > I learnt that FSM contains the Space map and vm the visibility map for a = given table. > =C2=A0 > =C2=A0=C2=A0=C2=A01. Why only some tables have it and others do not? The ones that don't have these files have never been processed by VACUUM. > =C2=A0=C2=A0=C2=A02. Why for some tables fsm is bigger than the table its= elf? Because the tables are very small. Yours, Laurenz Albe