Back-patch change to make DISCARD ALL release advisory locks.

Per discussion.

doc/src/sgml/ref/discard.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/ref/discard.sgml,v 1.2 2007/04/26 18:00:24 neilc Exp $
+$PostgreSQL: pgsql/doc/src/sgml/ref/discard.sgml,v 1.2.2.1 2008/11/27 00:34:49 tgl Exp $
 PostgreSQL documentation
 -->
 
@@ -70,15 +70,16 @@ DISCARD { ALL | PLANS | TEMPORARY | TEMP }
     <listitem>
      <para>
       Releases all temporary resources associated with the current
-      session and resets the session to its initial state. This has
-      the same effect as executing the following sequence of
-      statements:
+      session and resets the session to its initial state.
+      Currently, this has the same effect as executing the following sequence
+      of statements:
 <programlisting>
 SET SESSION AUTHORIZATION DEFAULT;
 RESET ALL;
 DEALLOCATE ALL;
 CLOSE ALL;
 UNLISTEN *;
+SELECT pg_advisory_unlock_all();
 DISCARD PLANS;
 DISCARD TEMP;
 </programlisting>

src/backend/commands/discard.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/discard.c,v 1.4 2008/01/01 19:45:49 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/discard.c,v 1.4.2.1 2008/11/27 00:34:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -19,6 +19,7 @@
 #include "commands/discard.h"
 #include "commands/prepare.h"
 #include "commands/variable.h"
+#include "storage/lock.h"
 #include "utils/plancache.h"
 #include "utils/portal.h"
 
@@ -66,6 +67,7 @@ DiscardAll(bool isTopLevel)
 	DropAllPreparedStatements();
 	PortalHashTableDeleteAll();
 	Async_UnlistenAll();
+	LockReleaseAll(USER_LOCKMETHOD, true);
 	ResetPlanCache();
 	ResetTempTableNamespace();
 }