Add RESET CONNECTION, to reset all aspects of a session.

Hans-J?rgen Sch?nig

src/backend/catalog/namespace.c

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.82 2006/03/05 15:58:22 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/namespace.c,v 1.83 2006/04/25 14:09:08 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -134,7 +134,6 @@ char	   *namespace_search_path = NULL;
 /* Local functions */
 static void recomputeNamespacePath(void);
 static void InitTempTableNamespace(void);
-static void RemoveTempRelations(Oid tempNamespaceId);
 static void RemoveTempRelationsCallback(int code, Datum arg);
 static void NamespaceCallback(Datum arg, Oid relid);
 
@@ -1729,7 +1728,7 @@ AtEOSubXact_Namespace(bool isCommit, SubTransactionId mySubid,
  * in order to clean out any relations that might have been created by
  * a crashed backend.
  */
-static void
+void
 RemoveTempRelations(Oid tempNamespaceId)
 {
 	ObjectAddress object;

src/backend/commands/async.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.129 2006/03/05 15:58:23 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/async.c,v 1.130 2006/04/25 14:09:10 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -127,7 +127,6 @@ static bool unlistenExitRegistered = false;
 bool		Trace_notify = false;
 
 
-static void Async_UnlistenAll(void);
 static void Async_UnlistenOnExit(int code, Datum arg);
 static void ProcessIncomingNotify(void);
 static void NotifyMyFrontEnd(char *relname, int32 listenerPID);
@@ -335,7 +334,7 @@ Async_Unlisten(const char *relname)
  *
  *--------------------------------------------------------------
  */
-static void
+void
 Async_UnlistenAll(void)
 {
 	Relation	lRel;

src/backend/commands/prepare.c

@@ -10,7 +10,7 @@
  * Copyright (c) 2002-2006, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.50 2006/04/22 01:25:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/prepare.c,v 1.51 2006/04/25 14:09:11 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -33,7 +33,6 @@
 #include "utils/hsearch.h"
 #include "utils/memutils.h"
 
-
 /*
  * The hash table in which prepared queries are stored. This is
  * per-backend: query plans are not shared between backends.
@@ -547,6 +546,30 @@ DeallocateQuery(DeallocateStmt *stmt)
 	DropPreparedStatement(stmt->name, true);
 }
 
+/*
+ * Remove all prepared plans from the backend.
+ */
+void
+DropAllPreparedStatements(void)
+{
+	PreparedStatement	*prep_statement;
+	HASH_SEQ_STATUS         status;
+
+	if	(!prepared_queries)
+		return;
+
+	hash_seq_init(&status, prepared_queries);
+
+	while ((prep_statement = (PreparedStatement *) hash_seq_search(&status)))
+	{
+		DropDependentPortals(prep_statement->context);
+
+		/* Flush the context holding the subsidiary data */
+		MemoryContextDelete(prep_statement->context);
+                hash_search(prepared_queries, prep_statement->stmt_name, HASH_REMOVE, NULL);
+	}
+}
+
 /*
  * Internal version of DEALLOCATE
  *

src/backend/parser/gram.y

@@ -11,7 +11,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.540 2006/04/24 22:59:19 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.541 2006/04/25 14:09:12 momjian Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -1244,6 +1244,12 @@ VariableResetStmt:
 					n->name = $2;
 					$$ = (Node *) n;
 				}
+			| RESET CONNECTION
+				{
+					VariableResetStmt *n = makeNode(VariableResetStmt);
+					n->name = "connection";
+					$$ = (Node *) n;
+				}
 			| RESET TIME ZONE
 				{
 					VariableResetStmt *n = makeNode(VariableResetStmt);

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 1.315 2006/04/10 21:53:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/misc/guc.c,v 1.316 2006/04/25 14:09:15 momjian Exp $
  *
  *--------------------------------------------------------------------
  */
@@ -32,6 +32,7 @@
 #include "catalog/namespace.h"
 #include "catalog/pg_type.h"
 #include "commands/async.h"
+#include "commands/prepare.h"
 #include "commands/variable.h"
 #include "commands/vacuum.h"
 #include "executor/executor.h"
@@ -53,6 +54,7 @@
 #include "postmaster/bgwriter.h"
 #include "postmaster/syslogger.h"
 #include "postmaster/postmaster.h"
+#include "storage/backendid.h"
 #include "storage/bufmgr.h"
 #include "storage/fd.h"
 #include "storage/freespace.h"
@@ -61,11 +63,13 @@
 #include "tcop/tcopprot.h"
 #include "utils/array.h"
 #include "utils/builtins.h"
+#include "utils/hsearch.h"
 #include "utils/memutils.h"
 #include "utils/pg_locale.h"
+#include "utils/portal.h"
+#include "utils/syscache.h"
 #include "pgstat.h"
 
-
 #ifndef PG_KRB_SRVTAB
 #define PG_KRB_SRVTAB ""
 #endif
@@ -4649,8 +4653,33 @@ GetPGVariableResultDesc(const char *name)
 void
 ResetPGVariable(const char *name)
 {
+	char			namespaceName[NAMEDATALEN];
+	Oid			namespaceId;
+
 	if (pg_strcasecmp(name, "all") == 0)
+		/* resetting all GUC variables */
 		ResetAllOptions();
+	else if	(pg_strcasecmp(name, "connection") == 0)
+	{
+		ResetAllOptions();
+
+		/* Clean temp-tables */
+		snprintf(namespaceName, sizeof(namespaceName), "pg_temp_%d",
+				 MyBackendId);
+		namespaceId = GetSysCacheOid(NAMESPACENAME,
+									 CStringGetDatum(namespaceName), 0, 0, 0);
+		RemoveTempRelations(namespaceId);
+
+		DropAllPreparedStatements();
+
+		Async_UnlistenAll();
+
+		/* Delete cursors, including WITH HOLD */
+		PortalHashTableDeleteAll();
+
+		if (IsTransactionBlock())
+			UserAbortTransactionBlock();
+	}
 	else
 		set_config_option(name,
 						  NULL,

src/backend/utils/mmgr/portalmem.c

@@ -12,7 +12,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.85 2006/03/05 15:58:49 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/mmgr/portalmem.c,v 1.86 2006/04/25 14:09:16 momjian Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -402,6 +402,9 @@ DropDependentPortals(MemoryContext queryContext)
 	HASH_SEQ_STATUS status;
 	PortalHashEnt *hentry;
 
+	if (PortalHashTable == NULL)
+		return;
+
 	hash_seq_init(&status, PortalHashTable);
 
 	while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
@@ -413,6 +416,30 @@ DropDependentPortals(MemoryContext queryContext)
 	}
 }
 
+/*
+ * Delete all WITH HOLD cursors, used by RESET CONNECTION
+ */
+void
+PortalHashTableDeleteAll(void)
+{
+	HASH_SEQ_STATUS status;
+	PortalHashEnt *hentry;
+
+	if (PortalHashTable == NULL)
+		return;
+
+	hash_seq_init(&status, PortalHashTable);
+
+	while ((hentry = (PortalHashEnt *) hash_seq_search(&status)) != NULL)
+	{
+		Portal		portal = hentry->portal;
+
+		if	((portal->cursorOptions & CURSOR_OPT_HOLD) &&
+			 portal->status != PORTAL_ACTIVE)
+			PortalDrop(portal, false);
+	}
+}
+
 
 /*
  * Pre-commit processing for portals.