Allow SQL-language functions to return the output of an INSERT/UPDATE/DELETE

RETURNING clause, not just a SELECT as formerly.

A side effect of this patch is that when a set-returning SQL function is used
in a FROM clause, performance is improved because the output is collected into
a tuplestore within the function, rather than using the less efficient
value-per-call mechanism.

3 files changed, 12 insertions, 6 deletions

diff --git a/src/include/executor/functions.h b/src/include/executor/functions.h
index b5451ad43b..61f782d18d 100644
--- a/src/include/executor/functions.h
+++ b/src/include/executor/functions.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/functions.h,v 1.31 2008/03/18 22:04:14 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/functions.h,v 1.32 2008/10/31 19:37:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -15,6 +15,7 @@
 #define FUNCTIONS_H
 
 #include "nodes/execnodes.h"
+#include "tcop/dest.h"
 
 
 extern Datum fmgr_sql(PG_FUNCTION_ARGS);
@@ -24,4 +25,6 @@ extern bool check_sql_fn_retval(Oid func_id, Oid rettype,
 					bool insertRelabels,
 					JunkFilter **junkFilter);
 
+extern DestReceiver *CreateSQLFunctionDestReceiver(void);
+
 #endif   /* FUNCTIONS_H */
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 8164de6a08..3fe16bd098 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.193 2008/10/29 00:00:39 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.194 2008/10/31 19:37:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -151,13 +151,15 @@ typedef enum
 /*
  * Return modes for functions returning sets.  Note values must be chosen
  * as separate bits so that a bitmask can be formed to indicate supported
- * modes.
+ * modes.  SFRM_Materialize_Random and SFRM_Materialize_Preferred are
+ * auxiliary flags about SFRM_Materialize mode, rather than separate modes.
  */
 typedef enum
 {
 	SFRM_ValuePerCall = 0x01,	/* one value returned per call */
 	SFRM_Materialize = 0x02,	/* result set instantiated in Tuplestore */
-	SFRM_Materialize_Random = 0x04		/* Tuplestore needs randomAccess */
+	SFRM_Materialize_Random = 0x04,		/* Tuplestore needs randomAccess */
+	SFRM_Materialize_Preferred = 0x08	/* caller prefers Tuplestore */
 } SetFunctionReturnMode;
 
 /*
diff --git a/src/include/tcop/dest.h b/src/include/tcop/dest.h
index 7484b84f76..5522f78c68 100644
--- a/src/include/tcop/dest.h
+++ b/src/include/tcop/dest.h
@@ -54,7 +54,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/tcop/dest.h,v 1.54 2008/01/01 19:45:59 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/tcop/dest.h,v 1.55 2008/10/31 19:37:56 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -86,7 +86,8 @@ typedef enum
 	DestSPI,					/* results sent to SPI manager */
 	DestTuplestore,				/* results sent to Tuplestore */
 	DestIntoRel,				/* results sent to relation (SELECT INTO) */
-	DestCopyOut					/* results sent to COPY TO code */
+	DestCopyOut,				/* results sent to COPY TO code */
+	DestSQLFunction				/* results sent to SQL-language func mgr */
 } CommandDest;
 
 /* ----------------