Support temporary setting of search path during CREATE SCHEMA; this

allows the example in the CREATE SCHEMA ref page to actually work now.
Also, clean up when the transaction that initially creates a temp-table
namespace is later aborted.  Simplify internal representation of search
path by folding special cases into the main list.

src/backend/access/transam/xact.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.121 2002/05/17 01:19:16 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/transam/xact.c,v 1.122 2002/05/17 20:53:33 tgl Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -164,6 +164,7 @@
 #include "access/xact.h"
 #include "catalog/heap.h"
 #include "catalog/index.h"
+#include "catalog/namespace.h"
 #include "commands/async.h"
 #include "commands/sequence.h"
 #include "commands/trigger.h"
@@ -1009,6 +1010,7 @@ CommitTransaction(void)
 	AtEOXact_hash();
 	AtEOXact_nbtree();
 	AtEOXact_rtree();
+	AtEOXact_Namespace(true);
 	AtCommit_Cache();
 	AtCommit_Locks();
 	AtEOXact_CatCache(true);
@@ -1112,6 +1114,7 @@ AbortTransaction(void)
 	AtEOXact_hash();
 	AtEOXact_nbtree();
 	AtEOXact_rtree();
+	AtEOXact_Namespace(false);
 	AtAbort_Cache();
 	AtEOXact_CatCache(false);
 	AtAbort_Memory();

src/backend/commands/schemacmds.c

@@ -8,13 +8,14 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/schemacmds.c,v 1.2 2002/04/27 03:45:01 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/schemacmds.c,v 1.3 2002/05/17 20:53:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
 
 #include "catalog/catalog.h"
+#include "catalog/namespace.h"
 #include "catalog/pg_namespace.h"
 #include "commands/schemacmds.h"
 #include "miscadmin.h"
@@ -32,6 +33,7 @@ CreateSchemaCommand(CreateSchemaStmt *stmt)
 {
 	const char *schemaName = stmt->schemaname;
 	const char *authId = stmt->authid;
+	Oid			namespaceId;
 	List	   *parsetree_list;
 	List	   *parsetree_item;
 	const char *owner_name;
@@ -85,11 +87,18 @@ CreateSchemaCommand(CreateSchemaStmt *stmt)
 			 schemaName);
 
 	/* Create the schema's namespace */
-	NamespaceCreate(schemaName, owner_userid);
+	namespaceId = NamespaceCreate(schemaName, owner_userid);
 
-	/* Let commands in the schema-element-list know about the schema */
+	/* Advance cmd counter to make the namespace visible */
 	CommandCounterIncrement();
 
+	/*
+	 * Temporarily make the new namespace be the front of the search path,
+	 * as well as the default creation target namespace.  This will be undone
+	 * at the end of this routine, or upon error.
+	 */
+	PushSpecialNamespace(namespaceId);
+
 	/*
 	 * Examine the list of commands embedded in the CREATE SCHEMA command,
 	 * and reorganize them into a sequentially executable order with no
@@ -124,6 +133,9 @@ CreateSchemaCommand(CreateSchemaStmt *stmt)
 		}
 	}
 
+	/* Reset search path to normal state */
+	PopSpecialNamespace(namespaceId);
+
 	/* Reset current user */
 	SetUserId(saved_userid);
 }

src/backend/utils/adt/name.c

@@ -12,7 +12,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/name.c,v 1.34 2002/04/26 01:24:08 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/adt/name.c,v 1.35 2002/05/17 20:53:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -235,7 +235,7 @@ session_user(PG_FUNCTION_ARGS)
 Datum
 current_schema(PG_FUNCTION_ARGS)
 {
-	List   *search_path = fetch_search_path();
+	List   *search_path = fetch_search_path(false);
 	char   *nspname;
 
 	if (search_path == NIL)
@@ -247,7 +247,7 @@ current_schema(PG_FUNCTION_ARGS)
 Datum
 current_schemas(PG_FUNCTION_ARGS)
 {
-	List   *search_path = fetch_search_path();
+	List   *search_path = fetch_search_path(false);
 	int		nnames = length(search_path);
 	Datum  *names;
 	int		i;

src/include/catalog/namespace.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: namespace.h,v 1.13 2002/05/17 01:19:19 tgl Exp $
+ * $Id: namespace.h,v 1.14 2002/05/17 20:53:33 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -72,13 +72,19 @@ extern char *NameListToString(List *names);
 
 extern bool isTempNamespace(Oid namespaceId);
 
+extern void PushSpecialNamespace(Oid namespaceId);
+extern void PopSpecialNamespace(Oid namespaceId);
+
+/* initialization & transaction cleanup code */
+extern void InitializeSearchPath(void);
+extern void AtEOXact_Namespace(bool isCommit);
+
 /* stuff for search_path GUC variable */
 extern char *namespace_search_path;
 
 extern const char *assign_search_path(const char *newval,
 									  bool doit, bool interactive);
-extern void InitializeSearchPath(void);
 
-extern List *fetch_search_path(void);
+extern List *fetch_search_path(bool includeImplicit);
 
 #endif   /* NAMESPACE_H */