Disallow VACUUM, ANALYZE, TRUNCATE on temp tables belonging to other

backends.  Given that temp tables now store data locally in the local
buffer manager, these things are not going to work safely.

src/backend/catalog/namespace.c

@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/catalog/namespace.c,v 1.35 2002/09/04 20:31:14 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/catalog/namespace.c,v 1.36 2002/09/23 20:43:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1217,6 +1217,28 @@ isTempNamespace(Oid namespaceId)
 	return false;
 }
 
+/*
+ * isOtherTempNamespace - is the given namespace some other backend's
+ * temporary-table namespace?
+ */
+bool
+isOtherTempNamespace(Oid namespaceId)
+{
+	bool		result;
+	char	   *nspname;
+
+	/* If it's my own temp namespace, say "false" */
+	if (isTempNamespace(namespaceId))
+		return false;
+	/* Else, if the namespace name starts with "pg_temp_", say "true" */
+	nspname = get_namespace_name(namespaceId);
+	if (!nspname)
+		return false;			/* no such namespace? */
+	result = (strncmp(nspname, "pg_temp_", 8) == 0);
+	pfree(nspname);
+	return result;
+}
+
 /*
  * PushSpecialNamespace - push a "special" namespace onto the front of the
  * search path.

src/backend/commands/analyze.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.46 2002/09/04 20:31:14 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/analyze.c,v 1.47 2002/09/23 20:43:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,6 +21,7 @@
 #include "catalog/catalog.h"
 #include "catalog/catname.h"
 #include "catalog/indexing.h"
+#include "catalog/namespace.h"
 #include "catalog/pg_operator.h"
 #include "catalog/pg_statistic.h"
 #include "catalog/pg_type.h"
@@ -215,6 +216,19 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
 		return;
 	}
 
+	/*
+	 * Silently ignore tables that are temp tables of other backends ---
+	 * trying to analyze these is rather pointless, since their
+	 * contents are probably not up-to-date on disk.  (We don't throw a
+	 * warning here; it would just lead to chatter during a database-wide
+	 * ANALYZE.)
+	 */
+	if (isOtherTempNamespace(RelationGetNamespace(onerel)))
+	{
+		relation_close(onerel, AccessShareLock);
+		return;
+	}
+
 	/*
 	 * We can ANALYZE any table except pg_statistic. See update_attstats
 	 */

src/backend/commands/tablecmds.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.43 2002/09/22 19:42:50 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/tablecmds.c,v 1.44 2002/09/23 20:43:40 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -367,6 +367,7 @@ TruncateRelation(const RangeVar *relation)
 			 RelationGetRelationName(rel));
 	}
 
+	/* Permissions checks */
 	if (!allowSystemTableMods && IsSystemRelation(rel))
 		elog(ERROR, "TRUNCATE cannot be used on system tables. '%s' is a system table",
 			 RelationGetRelationName(rel));
@@ -374,6 +375,13 @@ TruncateRelation(const RangeVar *relation)
 	if (!pg_class_ownercheck(relid, GetUserId()))
 		aclcheck_error(ACLCHECK_NOT_OWNER, RelationGetRelationName(rel));
 
+	/*
+	 * Don't allow truncate on temp tables of other backends ... their
+	 * local buffer manager is not going to cope.
+	 */
+	if (isOtherTempNamespace(RelationGetNamespace(rel)))
+		elog(ERROR, "TRUNCATE cannot be used on temp tables of other processes");
+
 	/*
 	 * Don't allow truncate on tables which are referenced by foreign keys
 	 */

src/backend/commands/vacuum.c

@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.239 2002/09/23 00:42:48 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.240 2002/09/23 20:43:41 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -775,6 +775,20 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
 		return;
 	}
 
+	/*
+	 * Silently ignore tables that are temp tables of other backends ---
+	 * trying to vacuum these will lead to great unhappiness, since their
+	 * contents are probably not up-to-date on disk.  (We don't throw a
+	 * warning here; it would just lead to chatter during a database-wide
+	 * VACUUM.)
+	 */
+	if (isOtherTempNamespace(RelationGetNamespace(onerel)))
+	{
+		relation_close(onerel, lmode);
+		CommitTransactionCommand(true);
+		return;
+	}
+
 	/*
 	 * Get a session-level lock too. This will protect our access to the
 	 * relation across multiple transactions, so that we can vacuum the

src/include/catalog/namespace.h

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2002, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: namespace.h,v 1.20 2002/09/04 20:31:37 momjian Exp $
+ * $Id: namespace.h,v 1.21 2002/09/23 20:43:41 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -76,6 +76,7 @@ extern RangeVar *makeRangeVarFromNameList(List *names);
 extern char *NameListToString(List *names);
 
 extern bool isTempNamespace(Oid namespaceId);
+extern bool isOtherTempNamespace(Oid namespaceId);
 
 extern void PushSpecialNamespace(Oid namespaceId);
 extern void PopSpecialNamespace(Oid namespaceId);