Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet the

SQL92 semantics, including support for ALL option.  All three can be used
in subqueries and views.  DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs.  I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!

1 files changed, 64 insertions, 6 deletions

diff --git a/src/backend/optimizer/plan/createplan.c b/src/backend/optimizer/plan/createplan.c
index cc308b4fc96..eb005121cd5 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.97 2000/09/29 18:21:33 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.98 2000/10/05 19:11:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -68,8 +68,6 @@ static IndexScan *make_indexscan(List *qptlist, List *qpqual, Index scanrelid,
 			   ScanDirection indexscandir);
 static TidScan *make_tidscan(List *qptlist, List *qpqual, Index scanrelid,
 			 List *tideval);
-static SubqueryScan *make_subqueryscan(List *qptlist, List *qpqual,
-									   Index scanrelid, Plan *subplan);
 static NestLoop *make_nestloop(List *tlist,
 							   List *joinclauses, List *otherclauses,
 							   Plan *lefttree, Plan *righttree,
@@ -86,7 +84,6 @@ static MergeJoin *make_mergejoin(List *tlist,
 								 Plan *lefttree, Plan *righttree,
 								 JoinType jointype);
 static void copy_path_costsize(Plan *dest, Path *src);
-static void copy_plan_costsize(Plan *dest, Plan *src);
 
 /*
  * create_plan
@@ -1109,7 +1106,7 @@ copy_path_costsize(Plan *dest, Path *src)
  * but it helps produce more reasonable-looking EXPLAIN output.
  * (Some callers alter the info after copying it.)
  */
-static void
+void
 copy_plan_costsize(Plan *dest, Plan *src)
 {
 	if (src)
@@ -1206,7 +1203,7 @@ make_tidscan(List *qptlist,
 	return node;
 }
 
-static SubqueryScan *
+SubqueryScan *
 make_subqueryscan(List *qptlist,
 				  List *qpqual,
 				  Index scanrelid,
@@ -1593,6 +1590,67 @@ make_unique(List *tlist, Plan *lefttree, List *distinctList)
 	return node;
 }
 
+/*
+ * distinctList is a list of SortClauses, identifying the targetlist items
+ * that should be considered by the SetOp filter.
+ */
+
+SetOp *
+make_setop(SetOpCmd cmd, List *tlist, Plan *lefttree,
+		   List *distinctList, AttrNumber flagColIdx)
+{
+	SetOp	   *node = makeNode(SetOp);
+	Plan	   *plan = &node->plan;
+	int			numCols = length(distinctList);
+	int			keyno = 0;
+	AttrNumber *dupColIdx;
+	List	   *slitem;
+
+	copy_plan_costsize(plan, lefttree);
+
+	/*
+	 * Charge one cpu_operator_cost per comparison per input tuple. We
+	 * assume all columns get compared at most of the tuples.
+	 */
+	plan->total_cost += cpu_operator_cost * plan->plan_rows * numCols;
+
+	/*
+	 * As for Group, we make the unsupported assumption that there will be
+	 * 10% as many tuples out as in.
+	 */
+	plan->plan_rows *= 0.1;
+	if (plan->plan_rows < 1)
+		plan->plan_rows = 1;
+
+	plan->state = (EState *) NULL;
+	plan->targetlist = tlist;
+	plan->qual = NIL;
+	plan->lefttree = lefttree;
+	plan->righttree = NULL;
+
+	/*
+	 * convert SortClause list into array of attr indexes, as wanted by
+	 * exec
+	 */
+	Assert(numCols > 0);
+	dupColIdx = (AttrNumber *) palloc(sizeof(AttrNumber) * numCols);
+
+	foreach(slitem, distinctList)
+	{
+		SortClause *sortcl = (SortClause *) lfirst(slitem);
+		TargetEntry *tle = get_sortgroupclause_tle(sortcl, tlist);
+
+		dupColIdx[keyno++] = tle->resdom->resno;
+	}
+
+	node->cmd = cmd;
+	node->numCols = numCols;
+	node->dupColIdx = dupColIdx;
+	node->flagColIdx = flagColIdx;
+
+	return node;
+}
+
 Result *
 make_result(List *tlist,
 			Node *resconstantqual,