Fix for breakage of C-coded SRFs, from Joe Conway.

Author: tglsfdc

src/backend/utils/fmgr/funcapi.c

@@ -7,7 +7,7 @@
  * Copyright (c) 2002, PostgreSQL Global Development Group
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/fmgr/funcapi.c,v 1.4 2002/08/29 17:14:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/fmgr/funcapi.c,v 1.5 2002/08/30 19:56:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -83,8 +83,16 @@ per_MultiFuncCall(PG_FUNCTION_ARGS)
 {
 	FuncCallContext *retval = (FuncCallContext *) fcinfo->flinfo->fn_extra;
 
-	/* make sure we start with a fresh slot */
-	if(retval->slot != NULL)
+	/*
+	 * Clear the TupleTableSlot, if present.  This is for safety's sake:
+	 * the Slot will be in a long-lived context (it better be, if the
+	 * FuncCallContext is pointing to it), but in most usage patterns the
+	 * tuples stored in it will be in the function's per-tuple context.
+	 * So at the beginning of each call, the Slot will hold a dangling
+	 * pointer to an already-recycled tuple.  We clear it out here.  (See
+	 * also the definition of TupleGetDatum() in funcapi.h!)
+	 */
+	if (retval->slot != NULL)
 		ExecClearTuple(retval->slot);
 
 	return retval;

src/include/funcapi.h

@@ -9,7 +9,7 @@
  *
  * Copyright (c) 2002, PostgreSQL Global Development Group
  *
- * $Id: funcapi.h,v 1.6 2002/08/29 17:14:33 tgl Exp $
+ * $Id: funcapi.h,v 1.7 2002/08/30 19:56:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -147,8 +147,12 @@ extern TupleTableSlot *TupleDescGetSlot(TupleDesc tupdesc);
 extern AttInMetadata *TupleDescGetAttInMetadata(TupleDesc tupdesc);
 extern HeapTuple BuildTupleFromCStrings(AttInMetadata *attinmeta, char **values);
 
+/*
+ * Note we pass shouldFree = false; this is needed because the tuple will
+ * typically be in a shorter-lived memory context than the TupleTableSlot.
+ */
 #define TupleGetDatum(_slot, _tuple) \
-	PointerGetDatum(ExecStoreTuple(_tuple, _slot, InvalidBuffer, true))
+	PointerGetDatum(ExecStoreTuple(_tuple, _slot, InvalidBuffer, false))
 
 
 /*----------

src/test/regress/expected/rangefuncs.out

@@ -1,3 +1,15 @@
+SELECT * FROM pg_settings WHERE name LIKE 'enable%';
+       name       | setting 
+------------------+---------
+ enable_hashjoin  | on
+ enable_indexscan | on
+ enable_mergejoin | on
+ enable_nestloop  | on
+ enable_seqscan   | on
+ enable_sort      | on
+ enable_tidscan   | on
+(7 rows)
+
 CREATE TABLE foo2(fooid int, f2 int);
 INSERT INTO foo2 VALUES(1, 11);
 INSERT INTO foo2 VALUES(2, 22);

src/test/regress/sql/rangefuncs.sql

@@ -1,3 +1,5 @@
+SELECT * FROM pg_settings WHERE name LIKE 'enable%';
+
 CREATE TABLE foo2(fooid int, f2 int);
 INSERT INTO foo2 VALUES(1, 11);
 INSERT INTO foo2 VALUES(2, 22);