Extend the set of frame options supported for window functions.

This patch allows the frame to start from CURRENT ROW (in either RANGE or
ROWS mode), and it also adds support for ROWS n PRECEDING and ROWS n FOLLOWING
start and end points.  (RANGE value PRECEDING/FOLLOWING isn't there yet ---
the grammar works, but that's all.)

Hitoshi Harada, reviewed by Pavel Stehule

6 files changed, 44 insertions, 15 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 4a4ea6b492b..9a1d19380c7 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.583 2010/02/07 20:48:11 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.584 2010/02/12 17:33:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201002071
+#define CATALOG_VERSION_NO	201002121
 
 #endif
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 866cd3ef3fd..4d9dfc4c82c 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.217 2010/01/05 23:25:36 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.218 2010/02/12 17:33:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1595,23 +1595,36 @@ typedef struct WindowAggState
 	FmgrInfo   *ordEqfunctions; /* equality funcs for ordering columns */
 	Tuplestorestate *buffer;	/* stores rows of current partition */
 	int			current_ptr;	/* read pointer # for current */
-	int			agg_ptr;		/* read pointer # for aggregates */
 	int64		spooled_rows;	/* total # of rows in buffer */
 	int64		currentpos;		/* position of current row in partition */
+	int64		frameheadpos;	/* current frame head position */
 	int64		frametailpos;	/* current frame tail position */
+	/* use struct pointer to avoid including windowapi.h here */
+	struct WindowObjectData *agg_winobj;	/* winobj for aggregate fetches */
+	int64		aggregatedbase; /* start row for current aggregates */
 	int64		aggregatedupto; /* rows before this one are aggregated */
 
-	MemoryContext wincontext;	/* context for partition-lifespan data */
+	int			frameOptions;	/* frame_clause options, see WindowDef */
+	ExprState  *startOffset;	/* expression for starting bound offset */
+	ExprState  *endOffset;		/* expression for ending bound offset */
+	Datum		startOffsetValue;	/* result of startOffset evaluation */
+	Datum		endOffsetValue;		/* result of endOffset evaluation */
+
+	MemoryContext partcontext;	/* context for partition-lifespan data */
+	MemoryContext aggcontext;	/* context for each aggregate data */
 	ExprContext *tmpcontext;	/* short-term evaluation context */
 
+	bool		all_first;		/* true if the scan is starting */
 	bool		all_done;		/* true if the scan is finished */
 	bool		partition_spooled;		/* true if all tuples in current
 										 * partition have been spooled into
 										 * tuplestore */
-	bool		more_partitions;/* true if there's more partitions after this
-								 * one */
-	bool		frametail_valid;/* true if frametailpos is known up to date
-								 * for current row */
+	bool		more_partitions;	/* true if there's more partitions after
+									 * this one */
+	bool		framehead_valid;	/* true if frameheadpos is known up to date
+									 * for current row */
+	bool		frametail_valid;	/* true if frametailpos is known up to date
+									 * for current row */
 
 	TupleTableSlot *first_part_slot;	/* first tuple of current or next
 										 * partition */
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index ffa6055a57a..0c3aecfa6e6 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.428 2010/02/08 04:33:54 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.429 2010/02/12 17:33:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -393,6 +393,8 @@ typedef struct WindowDef
 	List	   *partitionClause;	/* PARTITION BY expression list */
 	List	   *orderClause;	/* ORDER BY (list of SortBy) */
 	int			frameOptions;	/* frame_clause options, see below */
+	Node	   *startOffset;	/* expression for starting bound, if any */
+	Node	   *endOffset;		/* expression for ending bound, if any */
 	int			location;		/* parse location, or -1 if none/unknown */
 } WindowDef;
 
@@ -414,6 +416,15 @@ typedef struct WindowDef
 #define FRAMEOPTION_END_UNBOUNDED_FOLLOWING		0x00080 /* end is U. F. */
 #define FRAMEOPTION_START_CURRENT_ROW			0x00100 /* start is C. R. */
 #define FRAMEOPTION_END_CURRENT_ROW				0x00200 /* end is C. R. */
+#define FRAMEOPTION_START_VALUE_PRECEDING		0x00400 /* start is V. P. */
+#define FRAMEOPTION_END_VALUE_PRECEDING			0x00800 /* end is V. P. */
+#define FRAMEOPTION_START_VALUE_FOLLOWING		0x01000 /* start is V. F. */
+#define FRAMEOPTION_END_VALUE_FOLLOWING			0x02000 /* end is V. F. */
+
+#define FRAMEOPTION_START_VALUE \
+	(FRAMEOPTION_START_VALUE_PRECEDING | FRAMEOPTION_START_VALUE_FOLLOWING)
+#define FRAMEOPTION_END_VALUE \
+	(FRAMEOPTION_END_VALUE_PRECEDING | FRAMEOPTION_END_VALUE_FOLLOWING)
 
 #define FRAMEOPTION_DEFAULTS \
 	(FRAMEOPTION_RANGE | FRAMEOPTION_START_UNBOUNDED_PRECEDING | \
@@ -799,6 +810,8 @@ typedef struct WindowClause
 	List	   *partitionClause;	/* PARTITION BY list */
 	List	   *orderClause;	/* ORDER BY list */
 	int			frameOptions;	/* frame_clause options, see WindowDef */
+	Node	   *startOffset;	/* expression for starting bound, if any */
+	Node	   *endOffset;		/* expression for ending bound, if any */
 	Index		winref;			/* ID referenced by window functions */
 	bool		copiedOrder;	/* did we copy orderClause from refname? */
 } WindowClause;
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 48f75788585..b6640cfab33 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.115 2010/01/02 16:58:04 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.116 2010/02/12 17:33:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -552,6 +552,8 @@ typedef struct WindowAgg
 	AttrNumber *ordColIdx;		/* their indexes in the target list */
 	Oid		   *ordOperators;	/* equality operators for ordering columns */
 	int			frameOptions;	/* frame_clause options, see WindowDef */
+	Node	   *startOffset;	/* expression for starting bound, if any */
+	Node	   *endOffset;		/* expression for ending bound, if any */
 } WindowAgg;
 
 /* ----------------
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 024142250ac..ed00f86d278 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.124 2010/01/15 22:36:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.125 2010/02/12 17:33:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -62,7 +62,8 @@ extern WindowAgg *make_windowagg(PlannerInfo *root, List *tlist,
 			   int numWindowFuncs, Index winref,
 			   int partNumCols, AttrNumber *partColIdx, Oid *partOperators,
 			   int ordNumCols, AttrNumber *ordColIdx, Oid *ordOperators,
-			   int frameOptions, Plan *lefttree);
+			   int frameOptions, Node *startOffset, Node *endOffset,
+			   Plan *lefttree);
 extern Group *make_group(PlannerInfo *root, List *tlist, List *qual,
 		   int numGroupCols, AttrNumber *grpColIdx, Oid *grpOperators,
 		   double numGroups,
diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h
index e9c25e8d833..5065bd609e9 100644
--- a/src/include/parser/kwlist.h
+++ b/src/include/parser/kwlist.h
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/include/parser/kwlist.h,v 1.11 2010/02/08 04:33:55 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/include/parser/kwlist.h,v 1.12 2010/02/12 17:33:21 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,7 +53,7 @@ PG_KEYWORD("authorization", AUTHORIZATION, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("backward", BACKWARD, UNRESERVED_KEYWORD)
 PG_KEYWORD("before", BEFORE, UNRESERVED_KEYWORD)
 PG_KEYWORD("begin", BEGIN_P, UNRESERVED_KEYWORD)
-PG_KEYWORD("between", BETWEEN, TYPE_FUNC_NAME_KEYWORD)
+PG_KEYWORD("between", BETWEEN, COL_NAME_KEYWORD)
 PG_KEYWORD("bigint", BIGINT, COL_NAME_KEYWORD)
 PG_KEYWORD("binary", BINARY, TYPE_FUNC_NAME_KEYWORD)
 PG_KEYWORD("bit", BIT, COL_NAME_KEYWORD)