From c136eb02981566d56e950f12ab7ee4a6ea51d698 Mon Sep 17 00:00:00 2001
From: Bruce Momjian <bruce@momjian.us>
Date: Fri, 24 Nov 2023 17:56:28 -0500
Subject: [PATCH] doc:  mention vacuum's removal of commit timestamp
 information

Reported-by: Kyotaro HORIGUCHI

Discussion: https://postgr.es/m/20180622.172132.230342845.horiguchi.kyotaro@lab.ntt.co.jp

Co-authored-by: Kyotaro HORIGUCHI

Backpatch-through: 16
---
 doc/src/sgml/func.sgml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 13ce7f856a3..260a1c91733 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -25704,7 +25704,8 @@ SELECT collation for ('foo' COLLATE "de_DE");
     They only provide useful data when the
     <xref linkend="guc-track-commit-timestamp"/> configuration option is
     enabled, and only for transactions that were committed after it was
-    enabled.
+    enabled.  Commit timestamp information is routinely removed during
+    vacuum.
    </para>
 
    <table id="functions-commit-timestamp">
-- 
2.39.5