From 1120b99445a90ceba27f49e5cf86293f0628d06a Mon Sep 17 00:00:00 2001
From: Jan Wieck <JanWieck@Yahoo.com>
Date: Tue, 5 Jun 2007 20:00:41 +0000
Subject: [PATCH] The session_replication_role actually can be changed at will
 during a session regardless of the existence of cached plans. The plancache
 only needs to be invalidated so that rules affected by the new setting will
 be reflected in the new query plans.

Jan
---
 src/backend/utils/cache/plancache.c | 13 +------------
 src/backend/utils/misc/guc.c        | 15 ++++++++++-----
 src/include/utils/plancache.h       |  3 +--
 3 files changed, 12 insertions(+), 19 deletions(-)

diff --git a/src/backend/utils/cache/plancache.c b/src/backend/utils/cache/plancache.c
index 75810caa73..21aed6eadb 100644
--- a/src/backend/utils/cache/plancache.c
+++ b/src/backend/utils/cache/plancache.c
@@ -33,7 +33,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.9 2007/05/14 18:13:21 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/plancache.c,v 1.10 2007/06/05 20:00:41 wieck Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -944,14 +944,3 @@ InvalRelid(Oid relid, LOCKMODE lockmode, InvalRelidContext *context)
 	if (relid == context->inval_relid || context->inval_relid == InvalidOid)
 		context->plan->dead = true;
 }
-
-
-/*
- * HaveCachedPlans 
- *		Check if the plancache has stored any plans at all.
- */
-bool
-HaveCachedPlans(void)
-{
-	return (cached_plans_list != NIL);
-}
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index ec547a6670..3428d0a172 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -10,7 +10,7 @@
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.393 2007/06/03 17:07:34 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.394 2007/06/05 20:00:41 wieck Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -6270,24 +6270,29 @@ assign_defaultxactisolevel(const char *newval, bool doit, GucSource source)
 static const char *
 assign_session_replication_role(const char *newval, bool doit, GucSource source)
 {
-	if (HaveCachedPlans())
-		elog(ERROR, "session_replication_role cannot be changed "
-					"after prepared plans have been cached");
-
 	if (pg_strcasecmp(newval, "origin") == 0)
 	{
 		if (doit)
+		{
+			ResetPlanCache();
 			SessionReplicationRole = SESSION_REPLICATION_ROLE_ORIGIN;
+		}
 	}
 	else if (pg_strcasecmp(newval, "replica") == 0)
 	{
 		if (doit)
+		{
+			ResetPlanCache();
 			SessionReplicationRole = SESSION_REPLICATION_ROLE_REPLICA;
+		}
 	}
 	else if (pg_strcasecmp(newval, "local") == 0)
 	{
 		if (doit)
+		{
+			ResetPlanCache();
 			SessionReplicationRole = SESSION_REPLICATION_ROLE_LOCAL;
+		}
 	}
 	else
 		return NULL;
diff --git a/src/include/utils/plancache.h b/src/include/utils/plancache.h
index aebbbadaf5..d8152142aa 100644
--- a/src/include/utils/plancache.h
+++ b/src/include/utils/plancache.h
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/plancache.h,v 1.6 2007/04/16 18:21:07 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/plancache.h,v 1.7 2007/06/05 20:00:41 wieck Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -106,7 +106,6 @@ extern CachedPlan *RevalidateCachedPlan(CachedPlanSource *plansource,
 										bool useResOwner);
 extern void ReleaseCachedPlan(CachedPlan *plan, bool useResOwner);
 extern TupleDesc PlanCacheComputeResultDesc(List *stmt_list);
-extern bool HaveCachedPlans(void);
 
 extern void ResetPlanCache(void);