From: Bruce Momjian <bruce@momjian.us>
Date: Fri, 22 Apr 2005 15:53:27 +0000 (+0000)
Subject: Backpatch of LIMIT / FOR UPDATE behavior, but keep pre-7.3 mention in 8.0.X.
X-Git-Tag: REL8_0_3~29
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8e4b89ccf2884d9646eeaa4fe309d371726ebe24;p=thirdparty%2Fpostgresql.git

Backpatch of LIMIT / FOR UPDATE behavior, but keep pre-7.3 mention in 8.0.X.
---

diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 5046326e54c..c528010723b 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -1,5 +1,5 @@
 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.80.4.1 2005/01/22 23:23:53 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.80.4.2 2005/04/22 15:53:27 momjian Exp $
 PostgreSQL documentation
 -->
 
@@ -818,6 +818,16 @@ FOR UPDATE [ OF <replaceable class="parameter">table_name</replaceable> [, ...]
     rows; for example it can't be used with aggregation.
    </para>
 
+   <para>
+    It is possible for a <command>SELECT</> command using both 
+    <literal>LIMIT</literal> and  <literal>FOR UPDATE</literal> 
+    clauses to return fewer rows than specified by <literal>LIMIT</literal>.
+    This is because <literal>LIMIT</> selects a number of rows,
+    but might then block requesting a <literal>FOR UPDATE</literal> lock.
+    Once the <literal>SELECT</> unblocks, the query qualification might not
+    be met and the row not be returned by <literal>SELECT</>.
+   </para>
+
    <para>
     <literal>FOR UPDATE</literal> may appear before
     <literal>LIMIT</literal> for compatibility with