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 1wPdY2-000up8-1K for pgsql-novice@arkaria.postgresql.org; Wed, 20 May 2026 09:49:06 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.96) (envelope-from ) id 1wPdXz-006yQW-0c for pgsql-novice@arkaria.postgresql.org; Wed, 20 May 2026 09:49:04 +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 1wPdXy-006yQN-2q for pgsql-novice@lists.postgresql.org; Wed, 20 May 2026 09:49:03 +0000 Received: from mx1.alte-leipziger.de ([91.217.145.231]) by magus.postgresql.org with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.98.2) (envelope-from ) id 1wPdXx-00000000Wol-2L0K for pgsql-novice@lists.postgresql.org; Wed, 20 May 2026 09:49:03 +0000 X-CSE-ConnectionGUID: R+1qJZCOTgynQLJT+6FxNQ== X-CSE-MsgGUID: 1zVqKQBsSmSvV37XiNw4gA== From: "Subramanian,Ramachandran" To: "pgsql-novice@lists.postgresql.org" Subject: Why only some files have fsm and vm extensions Thread-Topic: Why only some files have fsm and vm extensions Thread-Index: AdzoPRfukldf0q8FTS2BEHFP6e2VnQ== Date: Wed, 20 May 2026 09:48:54 +0000 Message-ID: <6ad2ace1ccaa48c3a7fe41f785c359b3@alte-leipziger.de> Accept-Language: de-DE, en-US Content-Language: de-DE X-MS-Has-Attach: X-MS-TNEF-Correlator: x-tmase-matchedrid: DO4z3b1rdqMIu/vw30mA2EsWFBF5sab/tFwqAZvDV1S7V+mXEzZcN5qZ CYSsFJCiRO9zn4oBVzlIp1ndwoiO4D9BWL7GG0Ls07fOPS/+ckzPUfLIloz3/5XbFRQKOCo5JRY yjwxnVWmbIjXKaX4EjX7cGd19dSFd x-tm-as-user-approved-sender: No x-tm-as-user-blocked-sender: No x-tmase-result: 10--4.440600-8.000000 x-tm-snts-smtp: AF4247543F1C9D71804A855A0F784A15FEBFAC70763517C9E3F62DB59CB447CF2000:8 x-alsentwithgood: false Content-Type: multipart/alternative; boundary="_000_6ad2ace1ccaa48c3a7fe41f785c359b3alteleipzigerde_" MIME-Version: 1.0 X-GBS-PROC: U4I20n4ULWTIC0V85elGee1zZYdfL941q0TzD7ZGR1n4Z4k3jQBGz7KZAtAZmQeK X-GBS-PROCJOB: =?utf-8?Q?fs0XvSEEsG7P93c1D58mkNblS9sJAftKIVpwgGm4/F+ea53+JojYNwH9xpsX?= =?utf-8?Q?NJHFjf5QE6FbseCDIP6Fjn22Iw7JQgXGqNgndxYNz0hYR2+rvcoa61vutvpU?= =?utf-8?Q?TIuioSH/Ec8d72Sgs/NHjrCvt8UhO6NPzz0SNT2e4/Jj1uMVX50=3D?= List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Archived-At: Precedence: bulk --_000_6ad2ace1ccaa48c3a7fe41f785c359b3alteleipzigerde_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hallo, I am beginning to read the internals of Postgres , got curious and look= ed at the actual files . I learnt that FSM contains the Space map and vm the visibility map for a = given table. 1. Why only some tables have it and others do not=3F 2. Why for some tables fsm is bigger than the table itself=3F Not all the tables without fsm and vm are 0 bytes . There are tables that= are non zero but do not have fsm and vm. Thank you in advance for your time. LG Ram -rw-------. 1 postgres postgres 24576 May 18 09:40 1261_fsm -rw-------. 1 postgres postgres 8192 May 18 09:40 1261_vm -rw-------. 1 postgres postgres 8192 May 18 09:40 1262 -rw-------. 1 postgres postgres 24576 May 18 09:40 1262_fsm -rw-------. 1 postgres postgres 8192 May 18 09:40 1262_vm -rw-------. 1 postgres postgres 8192 May 18 09:40 2396 -rw-------. 1 postgres postgres 24576 May 18 09:40 2396_fsm -rw-------. 1 postgres postgres 8192 May 18 09:40 2396_vm postgres@lx90177:/var/lib/pgsql/AUFGABEN-VERWAL/data/global$ ls 1213 1214_fsm 1260 1261_fsm 1262_vm 2397 2677 2698 2965 = 3593 4176 4182 4186 6100 6244 6302 pg_internal.init 1213_fsm 1214_vm 1260_fsm 1261_vm 2396 2671 2694 2846 2966 = 4060 4177 4183 6000 6114 6245 6303 1213_vm 1232 1260_vm 1262 2396_fsm 2672 2695 2847 2967 = 4061 4178 4184 6001 6115 6246 pg_control 1214 1233 1261 1262_fsm 2396_vm 2676 2697 2964 3592 = 4175 4181 4185 6002 6243 6247 pg_filenode.map Freundliche Gr=FC=DFe i. A. Ramachandran Subramanian Zentralbereich Informationstechnologie Alte Leipziger Lebensversicherung a.G. Hallesche Krankenversicherung a.G. Alte Leipziger Lebensversicherung a.G., Alte Leipziger-Platz 1, 61440 Obe= rursel Vors. des Aufsichtsrats: Dr. Walter Botermann =B7 Vorstand: Christoph Boh= n (Vors.), Dr. J=FCrgen Bierbaum (stv. Vors.), Frank Kettnaker, Dr. Joche= n Kriegmeier, Alexander Mayer, Christian Pape, Wiltrud Pekarek, Udo Wilcs= ek Sitz Oberursel (Taunus) =B7 Rechtsform VVaG =B7 Amtsgericht Bad Homburg v= . d. H. HRB 1583 =B7 USt.-IdNr. DE 114106814 =20 Hallesche Krankenversicherung a.G., L=F6ffelstra=DFe 34-38, 70597 Stuttg= art Vors. des Aufsichtsrats: Dr. Walter Botermann =B7 Vorstand: Christoph Boh= n (Vors.), Dr. J=FCrgen Bierbaum (stv. Vors.), Frank Kettnaker, Dr. Joche= n Kriegmeier, Alexander Mayer, Christian Pape, Wiltrud Pekarek, Udo Wilcsek Sitz Stuttgart =B7 Rechtsform VVaG =B7 Amtsgericht Stuttgart HRB 2686 = =B7 USt.-IdNr. DE 147802285 Beitr=E4ge zu privaten Kranken- und Pflegekrankenversicherungen unterlieg= en nicht der Versicherungsteuer (=A7 4 Nr. 5 VersStG) =B7 Versicherungsle= istungen sowie Ums=E4tze aus Versicherungsvertreter-/Maklert=E4tigkeiten = sind umsatzsteuerfrei =20 =20 Die Pflichtangaben der ALH Gruppe gem=E4=DF =A7 35a GmbHG bzw. =A7 80 Akt= G finden Sie hier: https://www.alte-leipziger.de/impressum=20 ______________________ ALH Gruppe Alte Leipziger-Platz 1, 61440 Oberursel Tel.: +49 (6171) 66-4882 Fax: +49 (6171) 66-800-4882 E-Mail: ramachandran.subramanian@alte-leipziger.de www.alte-leipziger.de www.hallesche.de --_000_6ad2ace1ccaa48c3a7fe41f785c359b3alteleipzigerde_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Hallo,

 

  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 v= m the visibility map for a given table.

 

  1. Why only some tables have it and others do not=3F
  2. Why for some tables fsm is bigge= r than the table itself=3F

 

Not all the tables without fsm and vm are 0 by= tes . There are tables that are non zero but do not have fsm and vm.

 

 

Thank you in advance for your time.=

 

LG


Ram

 

 

-rw-------. 1 postgres postgres 24576 May 18 0= 9:40 1261_fsm

-rw-------. 1 postgres postgres  8192 May= 18 09:40 1261_vm

-rw-------. 1 postgres postgres  8192 May= 18 09:40 1262

-rw-------. 1 postgres postgres 24576 May 18 0= 9:40 1262_fsm

-rw-------. 1 postgres postgres  8192 May= 18 09:40 1262_vm

-rw-------. 1 postgres postgres  8192 May= 18 09:40 2396

-rw-------. 1 postgres postgres 24576 May 18 0= 9:40 2396_fsm

-rw-------. 1 postgres postgres  8192 May= 18 09:40 2396_vm

 

 

 

 

 

postgres@lx90177:/var/lib/pgsql/AUFGABEN-VERWA= L/data/global$ ls

1213      1214_fsm&nb= sp; 1260      1261_fsm  1262_vm  = 2397  2677  2698  2965  3593  4176  4182&n= bsp; 4186  6100  6244  6302     &= nbsp;       pg_internal.init

1213_fsm  1214_vm   1260_fsm&nb= sp; 1261_vm   2396      2671  269= 4  2846  2966  4060  4177  4183  6000 = 6114  6245  6303

1213_vm   1232   &nbs= p;  1260_vm   1262      2396_fsm&= nbsp; 2672  2695  2847  2967  4061  4178  4= 184  6001  6115  6246  pg_control

1214      1233 &= nbsp;    1261      1262_fsm = 2396_vm   2676  2697  2964  3592  4175&nbs= p; 4181  4185  6002  6243  6247  pg_filenode.map


Freundliche Gr=FC=DFe


i. A. Ramachandran Subrama= nian =20

Zentralbereich Informationst= echnologie

=20

Alte Leipziger Lebensversicherung a. G.<= /SPAN>

Hallesche Krankenversicherung a. G.

=20

______________________

ALH Gruppe
Alte Leipziger-Platz 1, 614= 40 Oberursel
Tel: +49 (6171) 66-4882
Fax: +49 (6171) 66-800-4882E-Mail: ramachandran.subramanian@alte-leipziger.de
www.alte-leipziger.de
www.hallesche.de

Alte Leipziger Lebensversich= erung a. G., Alte Leipziger-Platz 1, 61440 Oberursel

Vors. des Aufsichtsra= ts: Dr. Walter Botermann =B7 Vorstand: Christoph Bohn (Vors.), Dr. J=FCrg= en Bierbaum (stv. Vors.), Frank Kettnaker, Dr. Jochen Kriegmeier, Alexand= er Mayer, Christian Pape, Wiltrud Pekarek, Udo Wilcsek

Sitz Oberursel (Taunus) =B7 = Rechtsform VVaG =B7 Amtsgericht Bad Homburg v. d. H. HRB 1583 =B7 USt.-Id= Nr. DE 114106814


Hallesche Krankenversicherun= g a. G., L=F6ffelstra=DFe 34-38, 70597 Stuttgart

Vors. des Aufsichtsrats: Dr.= Walter Botermann =B7 Vorstand: Christoph Bohn (Vors.), Dr. J=FCrgen Bier= baum (stv. Vors.), Frank Kettnaker, Dr. Jochen Kriegmeier, Alexander Maye= r, Christian Pape, Wiltrud Pekarek, Udo Wilcsek

Sitz Stuttgart =B7 Rechtsfor= m VVaG =B7 Amtsgericht Stuttgart HRB 2686 =B7 USt.-IdNr. DE 147802285

Beitr=E4ge zu privaten Krank= en- und Pflegekrankenversicherungen unterliegen nicht der Versicherungste= uer (=A7 4 (1) Nr. 5 b VersStG) =B7 Versicherungsleistungen sowie Ums=E4t= ze aus Versicherungsvertreter-/Maklert=E4tigkeiten sind umsatzsteuerfrei<= /SPAN>


= Pflichtangaben der A= LH Gruppe gem=E4=DF =A7 35a GmbHG bzw. =A7 80 AktG --_000_6ad2ace1ccaa48c3a7fe41f785c359b3alteleipzigerde_--