From eb6af016fc04392c41106ac866072914bf66ecd0 Mon Sep 17 00:00:00 2001
From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 27 Jan 2012 12:40:37 -0500
Subject: [PATCH] Document that COUNT(*) might not need a seq scan any more.
Noted by Josh Kupershmidt.
---
doc/src/sgml/func.sgml | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 219ba9abf39..ec140040843 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>
--
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