Support window functions a la SQL:2008.

Hitoshi Harada, with some kibitzing from Heikki and Tom.

24 files changed, 362 insertions, 33 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 2f5ae35ef9f..21bbd429ae8 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.513 2008/12/19 18:25:19 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.514 2008/12/28 18:53:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200812192
+#define CATALOG_VERSION_NO	200812281
 
 #endif
diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h
index be632befc92..3082c58a582 100644
--- a/src/include/catalog/pg_proc.h
+++ b/src/include/catalog/pg_proc.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/catalog/pg_proc.h,v 1.533 2008/12/19 18:25:19 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/catalog/pg_proc.h,v 1.534 2008/12/28 18:53:59 tgl Exp $
  *
  * NOTES
  *	  The script catalog/genbki.sh reads this file and generates .bki
@@ -4635,6 +4635,38 @@ DESCR("record greater than or equal");
 DATA(insert OID = 2987 (  btrecordcmp	   PGNSP PGUID 12 1 0 0 f f f t f i 2 0 23 "2249 2249" _null_ _null_ _null_ _null_ btrecordcmp _null_ _null_ _null_ ));
 DESCR("btree less-equal-greater");
 
+/* SQL-spec window functions */
+DATA(insert OID = 3100 (  row_number	PGNSP PGUID 12 1 0 0 f t f f f i 0 0 20 "" _null_ _null_ _null_ _null_ window_row_number _null_ _null_ _null_ ));
+DESCR("row number within partition");
+DATA(insert OID = 3101 (  rank			PGNSP PGUID 12 1 0 0 f t f f f i 0 0 20 "" _null_ _null_ _null_ _null_ window_rank _null_ _null_ _null_ ));
+DESCR("integer rank with gaps");
+DATA(insert OID = 3102 (  dense_rank	PGNSP PGUID 12 1 0 0 f t f f f i 0 0 20 "" _null_ _null_ _null_ _null_ window_dense_rank _null_ _null_ _null_ ));
+DESCR("integer rank without gaps");
+DATA(insert OID = 3103 (  percent_rank	PGNSP PGUID 12 1 0 0 f t f f f i 0 0 701 "" _null_ _null_ _null_ _null_ window_percent_rank _null_ _null_ _null_ ));
+DESCR("fractional rank within partition");
+DATA(insert OID = 3104 (  cume_dist		PGNSP PGUID 12 1 0 0 f t f f f i 0 0 701 "" _null_ _null_ _null_ _null_ window_cume_dist _null_ _null_ _null_ ));
+DESCR("fractional row number within partition");
+DATA(insert OID = 3105 (  ntile			PGNSP PGUID 12 1 0 0 f t f t f i 1 0 23 "23" _null_ _null_ _null_ _null_ window_ntile _null_ _null_ _null_ ));
+DESCR("split rows into N groups");
+DATA(insert OID = 3106 (  lag			PGNSP PGUID 12 1 0 0 f t f t f i 1 0 2283 "2283" _null_ _null_ _null_ _null_ window_lag _null_ _null_ _null_ ));
+DESCR("fetch the preceding row value");
+DATA(insert OID = 3107 (  lag			PGNSP PGUID 12 1 0 0 f t f t f i 2 0 2283 "2283 23" _null_ _null_ _null_ _null_ window_lag_with_offset _null_ _null_ _null_ ));
+DESCR("fetch the Nth preceding row value");
+DATA(insert OID = 3108 (  lag			PGNSP PGUID 12 1 0 0 f t f t f i 3 0 2283 "2283 23 2283" _null_ _null_ _null_ _null_ window_lag_with_offset_and_default _null_ _null_ _null_ ));
+DESCR("fetch the Nth preceding row value with default");
+DATA(insert OID = 3109 (  lead			PGNSP PGUID 12 1 0 0 f t f t f i 1 0 2283 "2283" _null_ _null_ _null_ _null_ window_lead _null_ _null_ _null_ ));
+DESCR("fetch the following row value");
+DATA(insert OID = 3110 (  lead			PGNSP PGUID 12 1 0 0 f t f t f i 2 0 2283 "2283 23" _null_ _null_ _null_ _null_ window_lead_with_offset _null_ _null_ _null_ ));
+DESCR("fetch the Nth following row value");
+DATA(insert OID = 3111 (  lead			PGNSP PGUID 12 1 0 0 f t f t f i 3 0 2283 "2283 23 2283" _null_ _null_ _null_ _null_ window_lead_with_offset_and_default _null_ _null_ _null_ ));
+DESCR("fetch the Nth following row value with default");
+DATA(insert OID = 3112 (  first_value	PGNSP PGUID 12 1 0 0 f t f t f i 1 0 2283 "2283" _null_ _null_ _null_ _null_ window_first_value _null_ _null_ _null_ ));
+DESCR("fetch the first row value");
+DATA(insert OID = 3113 (  last_value	PGNSP PGUID 12 1 0 0 f t f t f i 1 0 2283 "2283" _null_ _null_ _null_ _null_ window_last_value _null_ _null_ _null_ ));
+DESCR("fetch the last row value");
+DATA(insert OID = 3114 (  nth_value		PGNSP PGUID 12 1 0 0 f t f t f i 2 0 2283 "2283 23" _null_ _null_ _null_ _null_ window_nth_value _null_ _null_ _null_ ));
+DESCR("fetch the Nth row value");
+
 
 /*
  * Symbolic values for provolatile column: these indicate whether the result
diff --git a/src/include/executor/nodeWindowAgg.h b/src/include/executor/nodeWindowAgg.h
new file mode 100644
index 00000000000..e8531037c07
--- /dev/null
+++ b/src/include/executor/nodeWindowAgg.h
@@ -0,0 +1,25 @@
+/*-------------------------------------------------------------------------
+ *
+ * nodeWindowAgg.h
+ *	  prototypes for nodeWindowAgg.c
+ *
+ *
+ * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ * $PostgreSQL: pgsql/src/include/executor/nodeWindowAgg.h,v 1.1 2008/12/28 18:54:00 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef NODEWINDOWAGG_H
+#define NODEWINDOWAGG_H
+
+#include "nodes/execnodes.h"
+
+extern int	ExecCountSlotsWindowAgg(WindowAgg *node);
+extern WindowAggState *ExecInitWindowAgg(WindowAgg *node, EState *estate, int eflags);
+extern TupleTableSlot *ExecWindowAgg(WindowAggState *node);
+extern void ExecEndWindowAgg(WindowAggState *node);
+extern void ExecReScanWindowAgg(WindowAggState *node, ExprContext *exprCtxt);
+
+#endif   /* NODEWINDOWAGG_H */
diff --git a/src/include/fmgr.h b/src/include/fmgr.h
index c348086fbc8..ee95676fe24 100644
--- a/src/include/fmgr.h
+++ b/src/include/fmgr.h
@@ -11,7 +11,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/fmgr.h,v 1.60 2008/09/03 22:34:50 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/fmgr.h,v 1.61 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -516,6 +516,8 @@ extern Oid	fmgr_internal_function(const char *proname);
 extern Oid	get_fn_expr_rettype(FmgrInfo *flinfo);
 extern Oid	get_fn_expr_argtype(FmgrInfo *flinfo, int argnum);
 extern Oid	get_call_expr_argtype(fmNodePtr expr, int argnum);
+extern bool get_fn_expr_arg_stable(FmgrInfo *flinfo, int argnum);
+extern bool get_call_expr_arg_stable(fmNodePtr expr, int argnum);
 
 /*
  * Routines in dfmgr.c
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 9aae040019b..258abdee6aa 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 1.196 2008/11/16 17:34:28 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.197 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -119,9 +119,12 @@ typedef struct ExprContext
 	ParamExecData *ecxt_param_exec_vals;		/* for PARAM_EXEC params */
 	ParamListInfo ecxt_param_list_info; /* for other param types */
 
-	/* Values to substitute for Aggref nodes in expression */
-	Datum	   *ecxt_aggvalues; /* precomputed values for Aggref nodes */
-	bool	   *ecxt_aggnulls;	/* null flags for Aggref nodes */
+	/*
+	 * Values to substitute for Aggref nodes in the expressions of an Agg node,
+	 * or for WindowFunc nodes within a WindowAgg node.
+	 */
+	Datum	   *ecxt_aggvalues; /* precomputed values for aggs/windowfuncs */
+	bool	   *ecxt_aggnulls;	/* null flags for aggs/windowfuncs */
 
 	/* Value to substitute for CaseTestExpr nodes in expression */
 	Datum		caseValue_datum;
@@ -512,6 +515,17 @@ typedef struct AggrefExprState
 } AggrefExprState;
 
 /* ----------------
+ *		WindowFuncExprState node
+ * ----------------
+ */
+typedef struct WindowFuncExprState
+{
+	ExprState	xprstate;
+	List	   *args;			/* states of argument expressions */
+	int			wfuncno;		/* ID number for wfunc within its plan node */
+} WindowFuncExprState;
+
+/* ----------------
  *		ArrayRefExprState node
  *
  * Note: array types can be fixed-length (typlen > 0), but only when the
@@ -1483,6 +1497,53 @@ typedef struct AggState
 } AggState;
 
 /* ----------------
+ *	WindowAggState information
+ * ----------------
+ */
+/* these structs are private in nodeWindowAgg.c: */
+typedef struct WindowStatePerFuncData *WindowStatePerFunc;
+typedef struct WindowStatePerAggData *WindowStatePerAgg;
+
+typedef struct WindowAggState
+{
+	ScanState	ss;					/* its first field is NodeTag */
+
+	/* these fields are filled in by ExecInitExpr: */
+	List	   *funcs;				/* all WindowFunc nodes in targetlist */
+	int			numfuncs;			/* total number of window functions */
+	int			numaggs;			/* number that are plain aggregates */
+
+	WindowStatePerFunc perfunc;		/* per-window-function information */
+	WindowStatePerAgg peragg;		/* per-plain-aggregate information */
+	FmgrInfo   *partEqfunctions;	/* equality funcs for partition columns */
+	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		frametailpos;		/* current frame tail position */
+	int64		aggregatedupto;		/* rows before this one are aggregated */
+
+	MemoryContext wincontext;		/* context for partition-lifespan data */
+	ExprContext *tmpcontext;		/* short-term evaluation context */
+
+	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 */
+
+	TupleTableSlot *first_part_slot;	/* first tuple of current or next
+										 * partition */
+
+	/* temporary slots for tuples fetched back from tuplestore */
+	TupleTableSlot *first_peer_slot;
+	TupleTableSlot *temp_slot_1;
+	TupleTableSlot *temp_slot_2;
+} WindowAggState;
+
+/* ----------------
  *	 UniqueState information
  *
  *		Unique nodes are used "on top of" sort nodes to discard
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 7383697f6ce..22649cdc073 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.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/nodes.h,v 1.216 2008/12/19 16:25:19 petere Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.217 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -66,6 +66,7 @@ typedef enum NodeTag
 	T_Sort,
 	T_Group,
 	T_Agg,
+	T_WindowAgg,
 	T_Unique,
 	T_Hash,
 	T_SetOp,
@@ -103,6 +104,7 @@ typedef enum NodeTag
 	T_SortState,
 	T_GroupState,
 	T_AggState,
+	T_WindowAggState,
 	T_UniqueState,
 	T_HashState,
 	T_SetOpState,
@@ -118,6 +120,7 @@ typedef enum NodeTag
 	T_Const,
 	T_Param,
 	T_Aggref,
+	T_WindowFunc,
 	T_ArrayRef,
 	T_FuncExpr,
 	T_OpExpr,
@@ -164,6 +167,7 @@ typedef enum NodeTag
 	T_ExprState = 400,
 	T_GenericExprState,
 	T_AggrefExprState,
+	T_WindowFuncExprState,
 	T_ArrayRefExprState,
 	T_FuncExprState,
 	T_ScalarArrayOpExprState,
@@ -350,6 +354,7 @@ typedef enum NodeTag
 	T_ResTarget,
 	T_TypeCast,
 	T_SortBy,
+	T_WindowDef,
 	T_RangeSubselect,
 	T_RangeFunction,
 	T_TypeName,
@@ -360,6 +365,7 @@ typedef enum NodeTag
 	T_OptionDefElem,
 	T_RangeTblEntry,
 	T_SortGroupClause,
+	T_WindowClause,
 	T_FkConstraint,
 	T_PrivGrantee,
 	T_FuncWithArgs,
@@ -383,6 +389,7 @@ typedef enum NodeTag
 	 */
 	T_TriggerData = 950,		/* in commands/trigger.h */
 	T_ReturnSetInfo,			/* in nodes/execnodes.h */
+	T_WindowObjectData,			/* private in nodeWindowAgg.c */
 	T_TIDBitmap					/* in nodes/tidbitmap.h */
 } NodeTag;
 
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 2f22475bf10..43c4452d781 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.384 2008/12/19 16:25:19 petere Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.385 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -120,6 +120,7 @@ typedef struct Query
 	IntoClause *intoClause;		/* target for SELECT INTO / CREATE TABLE AS */
 
 	bool		hasAggs;		/* has aggregates in tlist or havingQual */
+	bool		hasWindowFuncs;	/* has window functions in tlist */
 	bool		hasSubLinks;	/* has subquery SubLink */
 	bool		hasDistinctOn;	/* distinctClause is from DISTINCT ON */
 	bool		hasRecursive;	/* WITH RECURSIVE was specified */
@@ -137,6 +138,8 @@ typedef struct Query
 
 	Node	   *havingQual;		/* qualifications applied to groups */
 
+	List	   *windowClause;	/* a list of WindowClause's */
+
 	List	   *distinctClause; /* a list of SortGroupClause's */
 
 	List	   *sortClause;		/* a list of SortGroupClause's */
@@ -269,7 +272,8 @@ typedef struct TypeCast
  * agg_star indicates we saw a 'foo(*)' construct, while agg_distinct
  * indicates we saw 'foo(DISTINCT ...)'.  In either case, the construct
  * *must* be an aggregate call.  Otherwise, it might be either an
- * aggregate or some other kind of function.
+ * aggregate or some other kind of function.  However, if OVER is present
+ * it had better be an aggregate or window function.
  */
 typedef struct FuncCall
 {
@@ -279,6 +283,7 @@ typedef struct FuncCall
 	bool		agg_star;		/* argument was really '*' */
 	bool		agg_distinct;	/* arguments were labeled DISTINCT */
 	bool		func_variadic;	/* last argument was labeled VARIADIC */
+	struct WindowDef *over;		/* OVER clause, if any */
 	int			location;		/* token location, or -1 if unknown */
 } FuncCall;
 
@@ -376,6 +381,19 @@ typedef struct SortBy
 } SortBy;
 
 /*
+ * WindowDef - raw representation of WINDOW and OVER clauses
+ */
+typedef struct WindowDef
+{
+	NodeTag		type;
+	char	   *name;				/* window name (NULL in an OVER clause) */
+	char	   *refname;			/* referenced window name, if any */
+	List	   *partitionClause;	/* PARTITION BY expression list */
+	List	   *orderClause;		/* ORDER BY (list of SortBy) */
+	int			location;			/* parse location, or -1 if none/unknown */
+} WindowDef;
+
+/*
  * RangeSubselect - subquery appearing in a FROM clause
  */
 typedef struct RangeSubselect
@@ -662,7 +680,8 @@ typedef struct RangeTblEntry
 
 /*
  * SortGroupClause -
- *	   representation of ORDER BY, GROUP BY, DISTINCT, DISTINCT ON items
+ *		representation of ORDER BY, GROUP BY, PARTITION BY,
+ *		DISTINCT, DISTINCT ON items
  *
  * You might think that ORDER BY is only interested in defining ordering,
  * and GROUP/DISTINCT are only interested in defining equality.  However,
@@ -715,6 +734,31 @@ typedef struct SortGroupClause
 } SortGroupClause;
 
 /*
+ * WindowClause -
+ *		transformed representation of WINDOW and OVER clauses
+ *
+ * A parsed Query's windowClause list contains these structs.  "name" is set
+ * if the clause originally came from WINDOW, and is NULL if it originally
+ * was an OVER clause (but note that we collapse out duplicate OVERs).
+ * partitionClause and orderClause are lists of SortGroupClause structs.
+ * winref is an ID number referenced by WindowFunc nodes; it must be unique
+ * among the members of a Query's windowClause list.
+ * When refname isn't null, the partitionClause is always copied from there;
+ * the orderClause might or might not be copied.  (We don't implement
+ * framing clauses yet, but if we did, they are never copied, per spec.)
+ */
+typedef struct WindowClause
+{
+	NodeTag		type;
+	char	   *name;				/* window name (NULL in an OVER clause) */
+	char	   *refname;			/* referenced window name, if any */
+	List	   *partitionClause;	/* PARTITION BY list */
+	List	   *orderClause;		/* ORDER BY list */
+	Index		winref;				/* ID referenced by window functions */
+	bool		copiedOrder;		/* did we copy orderClause from refname? */
+} WindowClause;
+
+/*
  * RowMarkClause -
  *	   representation of FOR UPDATE/SHARE clauses
  *
@@ -858,6 +902,7 @@ typedef struct SelectStmt
 	Node	   *whereClause;	/* WHERE qualification */
 	List	   *groupClause;	/* GROUP BY clauses */
 	Node	   *havingClause;	/* HAVING conditional-expression */
+	List	   *windowClause;	/* WINDOW window_name AS (...), ... */
 	WithClause *withClause;		/* WITH clause */
 
 	/*
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 16c25fd6d0e..e320fd5fb4c 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.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/plannodes.h,v 1.105 2008/10/07 19:27:04 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/plannodes.h,v 1.106 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -537,6 +537,21 @@ typedef struct Agg
 } Agg;
 
 /* ----------------
+ *		window aggregate node
+ * ----------------
+ */
+typedef struct WindowAgg
+{
+	Plan		plan;
+	int			partNumCols;	/* number of columns in partition clause */
+	AttrNumber *partColIdx;		/* their indexes in the target list */
+	Oid		   *partOperators;	/* equality operators for partition columns */
+	int			ordNumCols;		/* number of columns in ordering clause */
+	AttrNumber *ordColIdx;		/* their indexes in the target list */
+	Oid		   *ordOperators;	/* equality operators for ordering columns */
+} WindowAgg;
+
+/* ----------------
  *		unique node
  * ----------------
  */
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index 2a2ea18520f..36edc80b9a6 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.143 2008/10/06 17:39:26 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.144 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -222,6 +222,21 @@ typedef struct Aggref
 	int			location;		/* token location, or -1 if unknown */
 } Aggref;
 
+/*
+ * WindowFunc
+ */
+typedef struct WindowFunc
+{
+	Expr		xpr;
+	Oid			winfnoid;		/* pg_proc Oid of the function */
+	Oid			wintype;		/* type Oid of result of the window function */
+	List	   *args;			/* arguments to the window function */
+	Index		winref;			/* index of associated WindowClause */
+	bool		winstar;		/* TRUE if argument list was really '*' */
+	bool		winagg;			/* is function a simple aggregate? */
+	int			location;		/* token location, or -1 if unknown */
+} WindowFunc;
+
 /* ----------------
  *	ArrayRef: describes an array subscripting operation
  *
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index 7b67d94700e..ac292692359 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.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/relation.h,v 1.165 2008/12/01 21:06:13 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.166 2008/12/28 18:54:00 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -171,6 +171,7 @@ typedef struct PlannerInfo
 								 * actual pathkeys afterwards */
 
 	List	   *group_pathkeys;		/* groupClause pathkeys, if any */
+	List	   *window_pathkeys;	/* pathkeys of bottom window, if any */
 	List	   *distinct_pathkeys;	/* distinctClause pathkeys, if any */
 	List	   *sort_pathkeys;		/* sortClause pathkeys, if any */
 
diff --git a/src/include/optimizer/clauses.h b/src/include/optimizer/clauses.h
index 3623aade6a7..f4e668bef30 100644
--- a/src/include/optimizer/clauses.h
+++ b/src/include/optimizer/clauses.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/optimizer/clauses.h,v 1.95 2008/10/09 19:27:40 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.96 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,6 +27,13 @@ typedef struct
 	Size		transitionSpace;	/* for pass-by-ref transition data */
 } AggClauseCounts;
 
+typedef struct
+{
+	int			numWindowFuncs;	/* total number of WindowFuncs found */
+	Index		maxWinRef;		/* windowFuncs[] is indexed 0 .. maxWinRef */
+	List	  **windowFuncs;	/* lists of WindowFuncs for each winref */
+} WindowFuncLists;
+
 
 extern Expr *make_opclause(Oid opno, Oid opresulttype, bool opretset,
 			  Expr *leftop, Expr *rightop);
@@ -47,8 +54,12 @@ extern Expr *make_ands_explicit(List *andclauses);
 extern List *make_ands_implicit(Expr *clause);
 
 extern bool contain_agg_clause(Node *clause);
+extern List *pull_agg_clause(Node *clause);
 extern void count_agg_clauses(Node *clause, AggClauseCounts *counts);
 
+extern bool contain_window_function(Node *clause);
+extern WindowFuncLists *find_window_functions(Node *clause, Index maxWinRef);
+
 extern double expression_returns_set_rows(Node *clause);
 
 extern bool contain_subplans(Node *clause);
diff --git a/src/include/optimizer/cost.h b/src/include/optimizer/cost.h
index 181327caa81..777f7f0fabe 100644
--- a/src/include/optimizer/cost.h
+++ b/src/include/optimizer/cost.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/optimizer/cost.h,v 1.93 2008/10/04 21:56:55 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/cost.h,v 1.94 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -85,6 +85,10 @@ extern void cost_agg(Path *path, PlannerInfo *root,
 		 int numGroupCols, double numGroups,
 		 Cost input_startup_cost, Cost input_total_cost,
 		 double input_tuples);
+extern void cost_windowagg(Path *path, PlannerInfo *root,
+			   int numWindowFuncs, int numPartCols, int numOrderCols,
+			   Cost input_startup_cost, Cost input_total_cost,
+			   double input_tuples);
 extern void cost_group(Path *path, PlannerInfo *root,
 		   int numGroupCols, double numGroups,
 		   Cost input_startup_cost, Cost input_total_cost,
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 641ebe42fb4..d6f5ff160f6 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.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/optimizer/planmain.h,v 1.114 2008/10/07 19:27:04 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.115 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -56,6 +56,11 @@ extern Agg *make_agg(PlannerInfo *root, List *tlist, List *qual,
 		 int numGroupCols, AttrNumber *grpColIdx, Oid *grpOperators,
 		 long numGroups, int numAggs,
 		 Plan *lefttree);
+extern WindowAgg *make_windowagg(PlannerInfo *root, List *tlist,
+			   int numWindowFuncs,
+			   int partNumCols, AttrNumber *partColIdx, Oid *partOperators,
+			   int ordNumCols, AttrNumber *ordColIdx, Oid *ordOperators,
+			   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/optimizer/tlist.h b/src/include/optimizer/tlist.h
index d2c7f42e05f..dabef328dea 100644
--- a/src/include/optimizer/tlist.h
+++ b/src/include/optimizer/tlist.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/optimizer/tlist.h,v 1.52 2008/08/07 19:35:02 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/tlist.h,v 1.53 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -21,7 +21,7 @@ extern TargetEntry *tlist_member(Node *node, List *targetlist);
 extern TargetEntry *tlist_member_ignore_relabel(Node *node, List *targetlist);
 
 extern List *flatten_tlist(List *tlist);
-extern List *add_to_flat_tlist(List *tlist, List *vars);
+extern List *add_to_flat_tlist(List *tlist, List *exprs);
 
 extern List *get_tlist_exprs(List *tlist, bool includeJunk);
 extern bool tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK);
diff --git a/src/include/parser/parse_agg.h b/src/include/parser/parse_agg.h
index bf3574e89fc..93b7f674e32 100644
--- a/src/include/parser/parse_agg.h
+++ b/src/include/parser/parse_agg.h
@@ -1,12 +1,12 @@
 /*-------------------------------------------------------------------------
  *
  * parse_agg.h
- *	  handle aggregates in parser
+ *	  handle aggregates and window functions in parser
  *
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/parser/parse_agg.h,v 1.36 2008/01/01 19:45:58 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_agg.h,v 1.37 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,8 +16,11 @@
 #include "parser/parse_node.h"
 
 extern void transformAggregateCall(ParseState *pstate, Aggref *agg);
+extern void transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
+									WindowDef *windef);
 
 extern void parseCheckAggregates(ParseState *pstate, Query *qry);
+extern void parseCheckWindowFuncs(ParseState *pstate, Query *qry);
 
 extern void build_aggregate_fnexprs(Oid *agg_input_types,
 						int agg_num_inputs,
diff --git a/src/include/parser/parse_clause.h b/src/include/parser/parse_clause.h
index ffea3466b5c..0463e7ae66e 100644
--- a/src/include/parser/parse_clause.h
+++ b/src/include/parser/parse_clause.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/parser/parse_clause.h,v 1.52 2008/08/07 01:11:52 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_clause.h,v 1.53 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -27,9 +27,15 @@ extern Node *transformWhereClause(ParseState *pstate, Node *clause,
 extern Node *transformLimitClause(ParseState *pstate, Node *clause,
 					 const char *constructName);
 extern List *transformGroupClause(ParseState *pstate, List *grouplist,
-					 List **targetlist, List *sortClause);
+					 List **targetlist, List *sortClause,
+					 bool isPartition);
 extern List *transformSortClause(ParseState *pstate, List *orderlist,
 					List **targetlist, bool resolveUnknown);
+
+extern List *transformWindowDefinitions(ParseState *pstate,
+										List *windowdefs,
+										List **targetlist);
+
 extern List *transformDistinctClause(ParseState *pstate,
 						List **targetlist, List *sortClause);
 extern List *transformDistinctOnClause(ParseState *pstate, List *distinctlist,
diff --git a/src/include/parser/parse_func.h b/src/include/parser/parse_func.h
index 8507a4ed7d5..b7023bf8d3d 100644
--- a/src/include/parser/parse_func.h
+++ b/src/include/parser/parse_func.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/parser/parse_func.h,v 1.62 2008/12/18 18:20:35 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_func.h,v 1.63 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -37,6 +37,7 @@ typedef enum
 	FUNCDETAIL_MULTIPLE,		/* too many matching functions */
 	FUNCDETAIL_NORMAL,			/* found a matching regular function */
 	FUNCDETAIL_AGGREGATE,		/* found a matching aggregate function */
+	FUNCDETAIL_WINDOWFUNC,		/* found a matching window function */
 	FUNCDETAIL_COERCION			/* it's a type coercion request */
 } FuncDetailCode;
 
@@ -44,7 +45,7 @@ typedef enum
 extern Node *ParseFuncOrColumn(ParseState *pstate,
 				  List *funcname, List *fargs,
 				  bool agg_star, bool agg_distinct, bool func_variadic,
-				  bool is_column, int location);
+				  WindowDef *over, bool is_column, int location);
 
 extern FuncDetailCode func_get_detail(List *funcname, List *fargs,
 				int nargs, Oid *argtypes,
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 8e0d3c201f2..0abe45df32c 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.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/parser/parse_node.h,v 1.58 2008/10/08 01:14:44 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/parser/parse_node.h,v 1.59 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -57,6 +57,12 @@
  * p_future_ctes: list of CommonTableExprs (WITH items) that are not yet
  * visible due to scope rules.  This is used to help improve error messages.
  *
+ * p_windowdefs: list of WindowDefs representing WINDOW and OVER clauses.
+ * We collect these while transforming expressions and then transform them
+ * afterwards (so that any resjunk tlist items needed for the sort/group
+ * clauses end up at the end of the query tlist).  A WindowDef's location in
+ * this list, counting from 1, is the winref number to use to reference it.
+ *
  * p_paramtypes: an array of p_numparams type OIDs for $n parameter symbols
  * (zeroth entry in array corresponds to $1).  If p_variableparams is true, the
  * set of param types is not predetermined; in that case, a zero array entry
@@ -77,6 +83,7 @@ typedef struct ParseState
 	List	   *p_varnamespace; /* current namespace for columns */
 	List	   *p_ctenamespace; /* current namespace for common table exprs */
 	List	   *p_future_ctes;	/* common table exprs not yet in namespace */
+	List	   *p_windowdefs;	/* raw representations of window clauses */
 	Oid		   *p_paramtypes;	/* OIDs of types for $n parameter symbols */
 	int			p_numparams;	/* allocated size of p_paramtypes[] */
 	int			p_next_resno;	/* next targetlist resno to assign */
@@ -84,6 +91,7 @@ typedef struct ParseState
 	Node	   *p_value_substitute;		/* what to replace VALUE with, if any */
 	bool		p_variableparams;
 	bool		p_hasAggs;
+	bool		p_hasWindowFuncs;
 	bool		p_hasSubLinks;
 	bool		p_is_insert;
 	bool		p_is_update;
diff --git a/src/include/rewrite/rewriteManip.h b/src/include/rewrite/rewriteManip.h
index 50b4443de0d..9387e71354b 100644
--- a/src/include/rewrite/rewriteManip.h
+++ b/src/include/rewrite/rewriteManip.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/rewrite/rewriteManip.h,v 1.47 2008/09/01 20:42:45 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/rewrite/rewriteManip.h,v 1.48 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -37,7 +37,9 @@ extern void AddInvertedQual(Query *parsetree, Node *qual);
 
 extern bool contain_aggs_of_level(Node *node, int levelsup);
 extern int	locate_agg_of_level(Node *node, int levelsup);
+extern int	locate_windowfunc(Node *node);
 extern bool checkExprHasAggs(Node *node);
+extern bool checkExprHasWindowFuncs(Node *node);
 extern bool checkExprHasSubLink(Node *node);
 
 extern Node *ResolveNew(Node *node, int target_varno, int sublevels_up,
diff --git a/src/include/utils/array.h b/src/include/utils/array.h
index 8a7f10451f0..6d0f5bf13c6 100644
--- a/src/include/utils/array.h
+++ b/src/include/utils/array.h
@@ -49,7 +49,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/array.h,v 1.72 2008/11/14 00:51:47 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/array.h,v 1.73 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -250,7 +250,7 @@ extern ArrayBuildState *accumArrayResult(ArrayBuildState *astate,
 extern Datum makeArrayResult(ArrayBuildState *astate,
 				MemoryContext rcontext);
 extern Datum makeMdArrayResult(ArrayBuildState *astate, int ndims,
-				  int *dims, int *lbs, MemoryContext rcontext);
+				  int *dims, int *lbs, MemoryContext rcontext, bool release);
 
 /*
  * prototypes for functions defined in arrayutils.c
diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h
index a00415aaa65..65be80c24b4 100644
--- a/src/include/utils/builtins.h
+++ b/src/include/utils/builtins.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/utils/builtins.h,v 1.328 2008/12/19 16:25:19 petere Exp $
+ * $PostgreSQL: pgsql/src/include/utils/builtins.h,v 1.329 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -988,6 +988,23 @@ extern Datum uuid_ne(PG_FUNCTION_ARGS);
 extern Datum uuid_cmp(PG_FUNCTION_ARGS);
 extern Datum uuid_hash(PG_FUNCTION_ARGS);
 
+/* windowfuncs.c */
+extern Datum window_row_number(PG_FUNCTION_ARGS);
+extern Datum window_rank(PG_FUNCTION_ARGS);
+extern Datum window_dense_rank(PG_FUNCTION_ARGS);
+extern Datum window_percent_rank(PG_FUNCTION_ARGS);
+extern Datum window_cume_dist(PG_FUNCTION_ARGS);
+extern Datum window_ntile(PG_FUNCTION_ARGS);
+extern Datum window_lag(PG_FUNCTION_ARGS);
+extern Datum window_lag_with_offset(PG_FUNCTION_ARGS);
+extern Datum window_lag_with_offset_and_default(PG_FUNCTION_ARGS);
+extern Datum window_lead(PG_FUNCTION_ARGS);
+extern Datum window_lead_with_offset(PG_FUNCTION_ARGS);
+extern Datum window_lead_with_offset_and_default(PG_FUNCTION_ARGS);
+extern Datum window_first_value(PG_FUNCTION_ARGS);
+extern Datum window_last_value(PG_FUNCTION_ARGS);
+extern Datum window_nth_value(PG_FUNCTION_ARGS);
+
 /* access/transam/twophase.c */
 extern Datum pg_prepared_xact(PG_FUNCTION_ARGS);
 
diff --git a/src/include/utils/errcodes.h b/src/include/utils/errcodes.h
index baecd7bafcb..4e393c62ac0 100644
--- a/src/include/utils/errcodes.h
+++ b/src/include/utils/errcodes.h
@@ -11,7 +11,7 @@
  *
  * Copyright (c) 2003-2008, PostgreSQL Global Development Group
  *
- * $PostgreSQL: pgsql/src/include/utils/errcodes.h,v 1.26 2008/10/04 21:56:55 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/errcodes.h,v 1.27 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -122,6 +122,8 @@
 #define ERRCODE_INDICATOR_OVERFLOW			MAKE_SQLSTATE('2','2', '0','2','2')
 #define ERRCODE_INTERVAL_FIELD_OVERFLOW		MAKE_SQLSTATE('2','2', '0','1','5')
 #define ERRCODE_INVALID_ARGUMENT_FOR_LOG	MAKE_SQLSTATE('2','2', '0','1','E')
+#define ERRCODE_INVALID_ARGUMENT_FOR_NTILE	MAKE_SQLSTATE('2','2', '0','1','4')
+#define ERRCODE_INVALID_ARGUMENT_FOR_NTH_VALUE	MAKE_SQLSTATE('2','2', '0','1','6')
 #define ERRCODE_INVALID_ARGUMENT_FOR_POWER_FUNCTION MAKE_SQLSTATE('2','2', '0', '1', 'F')
 #define ERRCODE_INVALID_ARGUMENT_FOR_WIDTH_BUCKET_FUNCTION	MAKE_SQLSTATE('2','2', '0', '1', 'G')
 #define ERRCODE_INVALID_CHARACTER_VALUE_FOR_CAST		MAKE_SQLSTATE('2','2', '0','1','8')
@@ -246,6 +248,7 @@
 #define ERRCODE_INSUFFICIENT_PRIVILEGE		MAKE_SQLSTATE('4','2', '5','0','1')
 #define ERRCODE_CANNOT_COERCE				MAKE_SQLSTATE('4','2', '8','4','6')
 #define ERRCODE_GROUPING_ERROR				MAKE_SQLSTATE('4','2', '8','0','3')
+#define ERRCODE_WINDOWING_ERROR				MAKE_SQLSTATE('4','2', 'P','2','0')
 #define ERRCODE_INVALID_RECURSION			MAKE_SQLSTATE('4','2', 'P','1','9')
 #define ERRCODE_INVALID_FOREIGN_KEY			MAKE_SQLSTATE('4','2', '8','3','0')
 #define ERRCODE_INVALID_NAME				MAKE_SQLSTATE('4','2', '6','0','2')
diff --git a/src/include/utils/tuplestore.h b/src/include/utils/tuplestore.h
index 9f9981ff41d..bb9f19cce2c 100644
--- a/src/include/utils/tuplestore.h
+++ b/src/include/utils/tuplestore.h
@@ -24,7 +24,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/tuplestore.h,v 1.26 2008/12/27 17:39:00 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/tuplestore.h,v 1.27 2008/12/28 18:54:01 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -68,6 +68,8 @@ extern void tuplestore_copy_read_pointer(Tuplestorestate *state,
 
 extern void tuplestore_trim(Tuplestorestate *state);
 
+extern bool tuplestore_in_memory(Tuplestorestate *state);
+
 extern bool tuplestore_gettupleslot(Tuplestorestate *state, bool forward,
 						TupleTableSlot *slot);
 extern bool tuplestore_advance(Tuplestorestate *state, bool forward);
diff --git a/src/include/windowapi.h b/src/include/windowapi.h
new file mode 100644
index 00000000000..25ba25fc50a
--- /dev/null
+++ b/src/include/windowapi.h
@@ -0,0 +1,64 @@
+/*-------------------------------------------------------------------------
+ *
+ * windowapi.h
+ *	  API for window functions to extract data from their window
+ *
+ * A window function does not receive its arguments in the normal way
+ * (and therefore the concept of strictness is irrelevant).  Instead it
+ * receives a "WindowObject", which it can fetch with PG_WINDOW_OBJECT()
+ * (note V1 calling convention must be used).  Correct call context can
+ * be tested with WindowObjectIsValid().  Although argument values are
+ * not passed, the call is correctly set up so that PG_NARGS() can be
+ * used and argument type information can be obtained with
+ * get_fn_expr_argtype(), get_fn_expr_arg_stable(), etc.
+ *
+ * Operations on the WindowObject allow the window function to find out
+ * the current row number, total number of rows in the partition, etc
+ * and to evaluate its argument expression(s) at various rows in the
+ * window partition.  See the header comments for each WindowObject API
+ * function in nodeWindowAgg.c for details.
+ *
+ *
+ * Portions Copyright (c) 2000-2008, PostgreSQL Global Development Group
+ *
+ * $PostgreSQL: pgsql/src/include/windowapi.h,v 1.1 2008/12/28 18:54:00 tgl Exp $
+ *
+ *-------------------------------------------------------------------------
+ */
+#ifndef WINDOWAPI_H
+#define WINDOWAPI_H
+
+/* values of "seektype" */
+#define WINDOW_SEEK_CURRENT 0
+#define WINDOW_SEEK_HEAD 1
+#define WINDOW_SEEK_TAIL 2
+
+/* this struct is private in nodeWindowAgg.c */
+typedef struct WindowObjectData *WindowObject;
+
+#define PG_WINDOW_OBJECT() ((WindowObject) fcinfo->context)
+
+#define WindowObjectIsValid(winobj) \
+	((winobj) != NULL && IsA(winobj, WindowObjectData))
+
+extern void *WinGetPartitionLocalMemory(WindowObject winobj, Size sz);
+
+extern int64 WinGetCurrentPosition(WindowObject winobj);
+extern int64 WinGetPartitionRowCount(WindowObject winobj);
+
+extern void WinSetMarkPosition(WindowObject winobj, int64 markpos);
+
+extern bool WinRowsArePeers(WindowObject winobj, int64 pos1, int64 pos2);
+
+extern Datum WinGetFuncArgInPartition(WindowObject winobj, int argno,
+									  int relpos, int seektype, bool set_mark,
+									  bool *isnull, bool *isout);
+
+extern Datum WinGetFuncArgInFrame(WindowObject winobj, int argno,
+								  int relpos, int seektype, bool set_mark,
+								  bool *isnull, bool *isout);
+
+extern Datum WinGetFuncArgCurrent(WindowObject winobj, int argno,
+								  bool *isnull);
+
+#endif   /* WINDOWAPI_H */