From 1c15aac53f3421fd38ae145118d3204f055ba955 Mon Sep 17 00:00:00 2001
From: Kevin Grittner <kgrittn@postgresql.org>
Date: Tue, 19 Jul 2016 16:25:53 -0500
Subject: Add comment & docs about no vacuum truncation with sto.

Omission noted by Andres Freund.
---
 doc/src/sgml/config.sgml | 9 +++++++++
 1 file changed, 9 insertions(+)

(limited to 'doc/src')

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 4e8c982dd59..c9e0ec2c021 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2091,6 +2091,15 @@ include_dir 'conf.d'
          transaction ID wraparound may occur in much shorter time frames.
         </para>
 
+        <para>
+         When this feature is enabled, freed space at the end of a relation
+         cannot be released to the operating system, since that could remove
+         information needed to detect the <literal>snapshot too old</>
+         condition.  All space allocated to a relation remains associated with
+         that relation for reuse only within that relation unless explicitly
+         freed (for example, with <command>VACUUM FULL</>).
+        </para>
+
         <para>
          This setting does not attempt to guarantee that an error will be
          generated under any particular circumstances.  In fact, if the
-- 
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