From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 27 Jan 2012 17:40:37 +0000 (-0500)
Subject: Document that COUNT(*) might not need a seq scan any more.
X-Git-Tag: REL9_2_BETA1~524
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=eb6af016fc04392c41106ac866072914bf66ecd0;p=postgresql

Document that COUNT(*) might not need a seq scan any more.

Noted by Josh Kupershmidt.
---

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 219ba9abf3..ec14004084 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -11102,8 +11102,10 @@ SELECT b1 = ANY((SELECT b2 FROM t2 ...)) FROM t1 ...;
 <programlisting>
 SELECT count(*) FROM sometable;
 </programlisting>
-    will be executed by <productname>PostgreSQL</productname> using a
-    sequential scan of the entire table.
+    will require effort proportional to the size of the table:
+    <productname>PostgreSQL</productname> will need to scan either the
+    entire table or the entirety of an index which includes all rows in
+    the table.
    </para>
   </note>