From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Thu, 23 Apr 2009 10:20:27 +0000 (+0000)
Subject: Mention that tables have a visibility map fork alongside the main fork
X-Git-Tag: REL8_4_BETA2~82
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=88f4d38d20ff7aec3b2f8e899b3f3d8daede6ae3;p=postgresql

Mention that tables have a visibility map fork alongside the main fork
and FSM.
---

diff --git a/doc/src/sgml/storage.sgml b/doc/src/sgml/storage.sgml
index 9b93ea5599..9e19aa63e4 100644
--- a/doc/src/sgml/storage.sgml
+++ b/doc/src/sgml/storage.sgml
@@ -1,4 +1,4 @@
-<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.26 2008/10/06 14:13:17 heikki Exp $ -->
+<!-- $PostgreSQL: pgsql/doc/src/sgml/storage.sgml,v 1.27 2009/04/23 10:20:27 heikki Exp $ -->
 
 <chapter id="storage">
 
@@ -134,7 +134,9 @@ or index's <firstterm>filenode</> number, which can be found in
 main file (aka. main fork), a <firstterm>free space map</> (see
 <xref linkend="storage-fsm">) that stores information about free space
 available in the relation, is stored in a file named after the filenode
-number, with the the <literal>_fsm</> suffix.
+number, with the <literal>_fsm</> suffix.  Tables also have a visibility map
+fork, with the <literal>_vm</> suffix, to track which pages are known to have
+no dead tuples and therefore need no vacuuming.
 </para>
 
 <caution>