From c78d8cd1464bc6b69fdc72f9ce51407c89554ece Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 8 Oct 2011 11:09:18 -0400
Subject: [PATCH] Note that index-only scans can affect idx_tup_fetch.

An index-only scan that avoids heap fetches will increment idx_tup_read
but not idx_tup_fetch.
---
 doc/src/sgml/monitoring.sgml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/monitoring.sgml b/doc/src/sgml/monitoring.sgml
index a19e3f06cc..b9dc1d2001 100644
--- a/doc/src/sgml/monitoring.sgml
+++ b/doc/src/sgml/monitoring.sgml
@@ -507,7 +507,8 @@ postgres: <replaceable>user</> <replaceable>database</> <replaceable>host</> <re
     considering bitmap scans, because <structfield>idx_tup_read</> counts
     index entries retrieved from the index while <structfield>idx_tup_fetch</>
     counts live rows fetched from the table; the latter will be less if any
-    dead or not-yet-committed rows are fetched using the index.
+    dead or not-yet-committed rows are fetched using the index, or if any
+    heap fetches are avoided by means of an index-only scan.
    </para>
   </note>