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

5 files changed, 33 insertions, 5 deletions

diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 4de0f7c87e9..271a7a2129b 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.460 2010/01/28 23:21:11 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.461 2010/02/12 17:33:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -718,6 +718,8 @@ _copyWindowAgg(WindowAgg *from)
 		COPY_POINTER_FIELD(ordOperators, from->ordNumCols * sizeof(Oid));
 	}
 	COPY_SCALAR_FIELD(frameOptions);
+	COPY_NODE_FIELD(startOffset);
+	COPY_NODE_FIELD(endOffset);
 
 	return newnode;
 }
@@ -1848,6 +1850,8 @@ _copyWindowClause(WindowClause *from)
 	COPY_NODE_FIELD(partitionClause);
 	COPY_NODE_FIELD(orderClause);
 	COPY_SCALAR_FIELD(frameOptions);
+	COPY_NODE_FIELD(startOffset);
+	COPY_NODE_FIELD(endOffset);
 	COPY_SCALAR_FIELD(winref);
 	COPY_SCALAR_FIELD(copiedOrder);
 
@@ -2076,6 +2080,8 @@ _copyWindowDef(WindowDef *from)
 	COPY_NODE_FIELD(partitionClause);
 	COPY_NODE_FIELD(orderClause);
 	COPY_SCALAR_FIELD(frameOptions);
+	COPY_NODE_FIELD(startOffset);
+	COPY_NODE_FIELD(endOffset);
 	COPY_LOCATION_FIELD(location);
 
 	return newnode;
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 319070add11..001c2096b4e 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -22,7 +22,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.381 2010/01/28 23:21:11 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.382 2010/02/12 17:33:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2056,6 +2056,8 @@ _equalWindowDef(WindowDef *a, WindowDef *b)
 	COMPARE_NODE_FIELD(partitionClause);
 	COMPARE_NODE_FIELD(orderClause);
 	COMPARE_SCALAR_FIELD(frameOptions);
+	COMPARE_NODE_FIELD(startOffset);
+	COMPARE_NODE_FIELD(endOffset);
 	COMPARE_LOCATION_FIELD(location);
 
 	return true;
@@ -2205,6 +2207,8 @@ _equalWindowClause(WindowClause *a, WindowClause *b)
 	COMPARE_NODE_FIELD(partitionClause);
 	COMPARE_NODE_FIELD(orderClause);
 	COMPARE_SCALAR_FIELD(frameOptions);
+	COMPARE_NODE_FIELD(startOffset);
+	COMPARE_NODE_FIELD(endOffset);
 	COMPARE_SCALAR_FIELD(winref);
 	COMPARE_SCALAR_FIELD(copiedOrder);
 
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c
index 76b22b4518e..c8c3202df45 100644
--- a/src/backend/nodes/nodeFuncs.c
+++ b/src/backend/nodes/nodeFuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/nodeFuncs.c,v 1.45 2010/01/02 16:57:46 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/nodeFuncs.c,v 1.46 2010/02/12 17:33:20 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1298,6 +1298,10 @@ expression_tree_walker(Node *node,
 					return true;
 				if (walker(wc->orderClause, context))
 					return true;
+				if (walker(wc->startOffset, context))
+					return true;
+				if (walker(wc->endOffset, context))
+					return true;
 			}
 			break;
 		case T_CommonTableExpr:
@@ -1950,6 +1954,8 @@ expression_tree_mutator(Node *node,
 				FLATCOPY(newnode, wc, WindowClause);
 				MUTATE(newnode->partitionClause, wc->partitionClause, List *);
 				MUTATE(newnode->orderClause, wc->orderClause, List *);
+				MUTATE(newnode->startOffset, wc->startOffset, Node *);
+				MUTATE(newnode->endOffset, wc->endOffset, Node *);
 				return (Node *) newnode;
 			}
 			break;
@@ -2475,6 +2481,10 @@ bool
 					return true;
 				if (walker(wd->orderClause, context))
 					return true;
+				if (walker(wd->startOffset, context))
+					return true;
+				if (walker(wd->endOffset, context))
+					return true;
 			}
 			break;
 		case T_RangeSubselect:
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 70950807908..593fe397d3f 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.381 2010/01/28 23:21:12 petere Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.382 2010/02/12 17:33:20 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -610,6 +610,8 @@ _outWindowAgg(StringInfo str, WindowAgg *node)
 		appendStringInfo(str, " %u", node->ordOperators[i]);
 
 	WRITE_INT_FIELD(frameOptions);
+	WRITE_NODE_FIELD(startOffset);
+	WRITE_NODE_FIELD(endOffset);
 }
 
 static void
@@ -2035,6 +2037,8 @@ _outWindowClause(StringInfo str, WindowClause *node)
 	WRITE_NODE_FIELD(partitionClause);
 	WRITE_NODE_FIELD(orderClause);
 	WRITE_INT_FIELD(frameOptions);
+	WRITE_NODE_FIELD(startOffset);
+	WRITE_NODE_FIELD(endOffset);
 	WRITE_UINT_FIELD(winref);
 	WRITE_BOOL_FIELD(copiedOrder);
 }
@@ -2326,6 +2330,8 @@ _outWindowDef(StringInfo str, WindowDef *node)
 	WRITE_NODE_FIELD(partitionClause);
 	WRITE_NODE_FIELD(orderClause);
 	WRITE_INT_FIELD(frameOptions);
+	WRITE_NODE_FIELD(startOffset);
+	WRITE_NODE_FIELD(endOffset);
 	WRITE_LOCATION_FIELD(location);
 }
 
diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c
index de0d25bb846..35ba22203fe 100644
--- a/src/backend/nodes/readfuncs.c
+++ b/src/backend/nodes/readfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.230 2010/01/02 16:57:46 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.231 2010/02/12 17:33:20 tgl Exp $
  *
  * NOTES
  *	  Path and Plan nodes do not have any readfuncs support, because we
@@ -279,6 +279,8 @@ _readWindowClause(void)
 	READ_NODE_FIELD(partitionClause);
 	READ_NODE_FIELD(orderClause);
 	READ_INT_FIELD(frameOptions);
+	READ_NODE_FIELD(startOffset);
+	READ_NODE_FIELD(endOffset);
 	READ_UINT_FIELD(winref);
 	READ_BOOL_FIELD(copiedOrder);