_SPI_execute_plan failed to return result tuple table to caller in

the ProcessUtility case, resulting in an intratransaction memory leak
if a utility command actually did return any tuples, as reported by
Dmitry Karasik.  Fix this and also make the behavior more consistent
for cases involving nested SPI operations and multiple query trees,
by ensuring that we store the state locally until it is ready to be
returned to the caller.

src/backend/executor/spi.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.141 2005/06/09 21:25:22 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.142 2005/10/01 18:43:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -104,6 +104,7 @@ SPI_connect(void)
 
 	_SPI_current = &(_SPI_stack[_SPI_connected]);
 	_SPI_current->processed = 0;
+	_SPI_current->lastoid = InvalidOid;
 	_SPI_current->tuptable = NULL;
 	_SPI_current->procCxt = NULL; /* in case we fail to create 'em */
 	_SPI_current->execCxt = NULL;
@@ -859,7 +860,7 @@ SPI_cursor_open(const char *name, void *plan,
 			break;
 	}
 
-	/* Reset SPI result */
+	/* Reset SPI result (note we deliberately don't touch lastoid) */
 	SPI_processed = 0;
 	SPI_tuptable = NULL;
 	_SPI_current->processed = 0;
@@ -1313,6 +1314,9 @@ _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 				  bool read_only, long tcount)
 {
 	volatile int res = 0;
+	volatile uint32 my_processed = 0;
+	volatile Oid my_lastoid = InvalidOid;
+	SPITupleTable * volatile my_tuptable = NULL;
 	Snapshot	saveActiveSnapshot;
 
 	/* Be sure to restore ActiveSnapshot on error exit */
@@ -1347,12 +1351,6 @@ _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 		else
 			paramLI = NULL;
 
-		/* Reset state (only needed in case string is empty) */
-		SPI_processed = 0;
-		SPI_lastoid = InvalidOid;
-		SPI_tuptable = NULL;
-		_SPI_current->tuptable = NULL;
-
 		/*
 		 * Setup error traceback support for ereport()
 		 */
@@ -1366,13 +1364,6 @@ _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 			List	   *query_list = lfirst(query_list_list_item);
 			ListCell   *query_list_item;
 
-			/* Reset state for each original parsetree */
-			/* (at most one of its querytrees will be marked canSetTag) */
-			SPI_processed = 0;
-			SPI_lastoid = InvalidOid;
-			SPI_tuptable = NULL;
-			_SPI_current->tuptable = NULL;
-
 			foreach(query_list_item, query_list)
 			{
 				Query	   *queryTree = (Query *) lfirst(query_list_item);
@@ -1383,6 +1374,10 @@ _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 				planTree = lfirst(plan_list_item);
 				plan_list_item = lnext(plan_list_item);
 
+				_SPI_current->processed = 0;
+				_SPI_current->lastoid = InvalidOid;
+				_SPI_current->tuptable = NULL;
+
 				if (queryTree->commandType == CMD_UTILITY)
 				{
 					if (IsA(queryTree->utilityStmt, CopyStmt))
@@ -1467,6 +1462,23 @@ _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 				}
 				FreeSnapshot(ActiveSnapshot);
 				ActiveSnapshot = NULL;
+				/*
+				 * The last canSetTag query sets the auxiliary values returned
+				 * to the caller.  Be careful to free any tuptables not
+				 * returned, to avoid intratransaction memory leak.
+				 */
+				if (queryTree->canSetTag)
+				{
+					my_processed = _SPI_current->processed;
+					my_lastoid = _SPI_current->lastoid;
+					SPI_freetuptable(my_tuptable);
+					my_tuptable = _SPI_current->tuptable;
+				}
+				else
+				{
+					SPI_freetuptable(_SPI_current->tuptable);
+					_SPI_current->tuptable = NULL;
+				}
 				/* we know that the receiver doesn't need a destroy call */
 				if (res < 0)
 					goto fail;
@@ -1490,6 +1502,11 @@ fail:
 
 	ActiveSnapshot = saveActiveSnapshot;
 
+	/* Save results for caller */
+	SPI_processed = my_processed;
+	SPI_lastoid = my_lastoid;
+	SPI_tuptable = my_tuptable;
+
 	return res;
 }
 
@@ -1497,9 +1514,7 @@ static int
 _SPI_pquery(QueryDesc *queryDesc, long tcount)
 {
 	int			operation = queryDesc->operation;
-	CommandDest	origDest = queryDesc->dest->mydest;
 	int			res;
-	Oid			save_lastoid;
 
 	switch (operation)
 	{
@@ -1510,6 +1525,11 @@ _SPI_pquery(QueryDesc *queryDesc, long tcount)
 				res = SPI_OK_SELINTO;
 				queryDesc->dest = None_Receiver;	/* don't output results */
 			}
+			else if (queryDesc->dest->mydest != SPI)
+			{
+				/* Don't return SPI_OK_SELECT if we're discarding result */
+				res = SPI_OK_UTILITY;
+			}
 			break;
 		case CMD_INSERT:
 			res = SPI_OK_INSERT;
@@ -1536,7 +1556,7 @@ _SPI_pquery(QueryDesc *queryDesc, long tcount)
 	ExecutorRun(queryDesc, ForwardScanDirection, tcount);
 
 	_SPI_current->processed = queryDesc->estate->es_processed;
-	save_lastoid = queryDesc->estate->es_lastoid;
+	_SPI_current->lastoid = queryDesc->estate->es_lastoid;
 
 	if (operation == CMD_SELECT && queryDesc->dest->mydest == SPI)
 	{
@@ -1549,19 +1569,6 @@ _SPI_pquery(QueryDesc *queryDesc, long tcount)
 
 	ExecutorEnd(queryDesc);
 
-	/* Test origDest here so that SPI_processed gets set in SELINTO case */
-	if (origDest == SPI)
-	{
-		SPI_processed = _SPI_current->processed;
-		SPI_lastoid = save_lastoid;
-		SPI_tuptable = _SPI_current->tuptable;
-	}
-	else if (res == SPI_OK_SELECT)
-	{
-		/* Don't return SPI_OK_SELECT if we discarded the result */
-		res = SPI_OK_UTILITY;
-	}
-
 #ifdef SPI_EXECUTOR_STATS
 	if (ShowExecutorStats)
 		ShowUsage("SPI EXECUTOR STATS");
@@ -1615,7 +1622,7 @@ _SPI_cursor_operation(Portal portal, bool forward, long count,
 	if (_SPI_begin_call(true) < 0)
 		elog(ERROR, "SPI cursor operation called while not connected");
 
-	/* Reset the SPI result */
+	/* Reset the SPI result (note we deliberately don't touch lastoid) */
 	SPI_processed = 0;
 	SPI_tuptable = NULL;
 	_SPI_current->processed = 0;

src/include/executor/spi_priv.h

@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/spi_priv.h,v 1.22 2004/12/31 22:03:29 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/executor/spi_priv.h,v 1.23 2005/10/01 18:43:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,8 +18,11 @@
 
 typedef struct
 {
+	/* current results */
 	uint32		processed;		/* by Executor */
+	Oid			lastoid;
 	SPITupleTable *tuptable;
+
 	MemoryContext procCxt;		/* procedure context */
 	MemoryContext execCxt;		/* executor context */
 	MemoryContext savedcxt;