Expose more cursor-related functionality in SPI: specifically, allow

access to the planner's cursor-related planning options, and provide new
FETCH/MOVE routines that allow access to the full power of those commands.
Small refactoring of planner(), pg_plan_query(), and pg_plan_queries()
APIs to make it convenient to pass the planning options down from SPI.

This is the core-code portion of Pavel Stehule's patch for scrollable
cursor support in plpgsql; I'll review and apply the plpgsql changes
separately.

4 files changed, 22 insertions, 15 deletions

diff --git a/src/include/executor/spi.h b/src/include/executor/spi.h
index 80c8993c7c3..c996f644c03 100644
--- a/src/include/executor/spi.h
+++ b/src/include/executor/spi.h
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/executor/spi.h,v 1.60 2007/03/25 23:27:59 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/executor/spi.h,v 1.61 2007/04/16 01:14:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -20,8 +20,8 @@
 #include "postgres.h"
 
 /*
- *	These are not needed by this file, but used by other programs
- *	using SPI
+ *	Most of these are not needed by this file, but may be used by
+ *	user-written code that uses SPI
  */
 #include "access/heapam.h"
 #include "access/xact.h"
@@ -32,6 +32,7 @@
 #include "executor/executor.h"
 #include "nodes/execnodes.h"
 #include "nodes/params.h"
+#include "nodes/parsenodes.h"
 #include "nodes/plannodes.h"
 #include "nodes/primnodes.h"
 #include "nodes/relation.h"
@@ -105,6 +106,8 @@ extern int	SPI_execute_snapshot(SPIPlanPtr plan,
 					 Snapshot crosscheck_snapshot,
 					 bool read_only, long tcount);
 extern SPIPlanPtr SPI_prepare(const char *src, int nargs, Oid *argtypes);
+extern SPIPlanPtr SPI_prepare_cursor(const char *src, int nargs, Oid *argtypes,
+									 int cursorOptions);
 extern SPIPlanPtr SPI_saveplan(SPIPlanPtr plan);
 extern int	SPI_freeplan(SPIPlanPtr plan);
 
@@ -136,6 +139,8 @@ extern Portal SPI_cursor_open(const char *name, SPIPlanPtr plan,
 extern Portal SPI_cursor_find(const char *name);
 extern void SPI_cursor_fetch(Portal portal, bool forward, long count);
 extern void SPI_cursor_move(Portal portal, bool forward, long count);
+extern void SPI_scroll_cursor_fetch(Portal, FetchDirection direction, long count);
+extern void SPI_scroll_cursor_move(Portal, FetchDirection direction, long count);
 extern void SPI_cursor_close(Portal portal);
 
 extern void AtEOXact_SPI(bool isCommit);
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index bc421e265fc..dbc29642f06 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.345 2007/04/12 06:53:48 neilc Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.346 2007/04/16 01:14:57 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1429,11 +1429,12 @@ typedef struct CommentStmt
  *		Declare Cursor Statement
  * ----------------------
  */
-#define CURSOR_OPT_BINARY		0x0001
-#define CURSOR_OPT_SCROLL		0x0002
-#define CURSOR_OPT_NO_SCROLL	0x0004
-#define CURSOR_OPT_INSENSITIVE	0x0008
-#define CURSOR_OPT_HOLD			0x0010
+#define CURSOR_OPT_BINARY		0x0001		/* BINARY */
+#define CURSOR_OPT_SCROLL		0x0002		/* SCROLL explicitly given */
+#define CURSOR_OPT_NO_SCROLL	0x0004		/* NO SCROLL explicitly given */
+#define CURSOR_OPT_INSENSITIVE	0x0008		/* INSENSITIVE (unimplemented) */
+#define CURSOR_OPT_HOLD			0x0010		/* WITH HOLD */
+#define CURSOR_OPT_FAST_PLAN	0x0020		/* prefer fast-start plan */
 
 typedef struct DeclareCursorStmt
 {
diff --git a/src/include/optimizer/planner.h b/src/include/optimizer/planner.h
index c243cdbc356..b568a7dbe82 100644
--- a/src/include/optimizer/planner.h
+++ b/src/include/optimizer/planner.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/planner.h,v 1.38 2007/02/20 17:32:17 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/planner.h,v 1.39 2007/04/16 01:14:58 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -18,7 +18,7 @@
 #include "nodes/relation.h"
 
 
-extern PlannedStmt *planner(Query *parse, bool isCursor, int cursorOptions,
+extern PlannedStmt *planner(Query *parse, int cursorOptions,
 		ParamListInfo boundParams);
 extern Plan *subquery_planner(PlannerGlobal *glob, Query *parse,
 							  Index level, double tuple_fraction,
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index 098cb1da1ed..613d9a99837 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/tcop/tcopprot.h,v 1.88 2007/03/07 13:35:03 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/tcop/tcopprot.h,v 1.89 2007/04/16 01:14:58 tgl Exp $
  *
  * OLD COMMENTS
  *	  This file was created so that other c files could get the two
@@ -49,9 +49,10 @@ extern List *pg_parse_and_rewrite(const char *query_string,
 extern List *pg_parse_query(const char *query_string);
 extern List *pg_analyze_and_rewrite(Node *parsetree, const char *query_string,
 					   Oid *paramTypes, int numParams);
-extern PlannedStmt *pg_plan_query(Query *querytree, ParamListInfo boundParams);
-extern List *pg_plan_queries(List *querytrees, ParamListInfo boundParams,
-				bool needSnapshot);
+extern PlannedStmt *pg_plan_query(Query *querytree, int cursorOptions,
+								  ParamListInfo boundParams);
+extern List *pg_plan_queries(List *querytrees, int cursorOptions,
+							 ParamListInfo boundParams, bool needSnapshot);
 
 extern bool assign_max_stack_depth(int newval, bool doit, GucSource source);