From 6c9ad72e4e61dbf05f34146cb67706dd675a38f0 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Mon, 30 Nov 2020 18:50:06 -0300
Subject: [PATCH v5] Note CIC and RC in vacuum's doc

Per James Coleman
---
 doc/src/sgml/maintenance.sgml | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml
index 4d8ad754f8..d68d7f936e 100644
--- a/doc/src/sgml/maintenance.sgml
+++ b/doc/src/sgml/maintenance.sgml
@@ -159,7 +159,17 @@
     concurrency control (<acronym>MVCC</acronym>, see <xref linkend="mvcc"/>): the row version
     must not be deleted while it is still potentially visible to other
     transactions. But eventually, an outdated or deleted row version is no
-    longer of interest to any transaction. The space it occupies must then be
+    longer of interest to any transaction.
+    <footnote>
+     <para>
+      Note that <command>VACUUM</literal> needs to retain tuples that are
+      nominally visible to transactions running
+      <command>CREATE INDEX CONCURRENTLY</command> or
+      <command>REINDEX CONCURRENTLY</command>, even when run on tables
+      other than the tables being indexed.
+     </para>
+    </footnote>
+    The space it occupies must then be
     reclaimed for reuse by new rows, to avoid unbounded growth of disk
     space requirements. This is done by running <command>VACUUM</command>.
    </para>
-- 
2.20.1