First stage of reclaiming memory in executor by resetting short-term

memory contexts.  Currently, only leaks in expressions executed as
quals or projections are handled.  Clean up some old dead cruft in
executor while at it --- unused fields in state nodes, that sort of thing.

src/backend/optimizer/plan/createplan.c

@@ -10,7 +10,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.93 2000/06/18 22:44:07 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/createplan.c,v 1.94 2000/07/12 02:37:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -66,7 +66,7 @@ static NestLoop *make_nestloop(List *qptlist, List *qpqual, Plan *lefttree,
 			  Plan *righttree);
 static HashJoin *make_hashjoin(List *tlist, List *qpqual,
 			  List *hashclauses, Plan *lefttree, Plan *righttree);
-static Hash *make_hash(List *tlist, Var *hashkey, Plan *lefttree);
+static Hash *make_hash(List *tlist, Node *hashkey, Plan *lefttree);
 static MergeJoin *make_mergejoin(List *tlist, List *qpqual,
 			   List *mergeclauses, Plan *righttree, Plan *lefttree);
 static void copy_path_costsize(Plan *dest, Path *src);
@@ -664,7 +664,7 @@ create_hashjoin_node(HashPath *best_path,
 	List	   *hashclauses;
 	HashJoin   *join_node;
 	Hash	   *hash_node;
-	Var		   *innerhashkey;
+	Node	   *innerhashkey;
 
 	/*
 	 * NOTE: there will always be exactly one hashclause in the list
@@ -694,7 +694,7 @@ create_hashjoin_node(HashPath *best_path,
 											   (Index) 0));
 
 	/* Now the righthand op of the sole hashclause is the inner hash key. */
-	innerhashkey = get_rightop(lfirst(hashclauses));
+	innerhashkey = (Node *) get_rightop(lfirst(hashclauses));
 
 	/*
 	 * Build the hash node and hash join node.
@@ -1103,7 +1103,7 @@ make_hashjoin(List *tlist,
 }
 
 static Hash *
-make_hash(List *tlist, Var *hashkey, Plan *lefttree)
+make_hash(List *tlist, Node *hashkey, Plan *lefttree)
 {
 	Hash	   *node = makeNode(Hash);
 	Plan	   *plan = &node->plan;

src/backend/optimizer/plan/subselect.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.38 2000/06/18 22:44:09 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.39 2000/07/12 02:37:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -649,7 +649,7 @@ SS_finalize_plan(Plan *plan)
 			break;
 
 		case T_Hash:
-			finalize_primnode((Node *) ((Hash *) plan)->hashkey,
+			finalize_primnode(((Hash *) plan)->hashkey,
 							  &results);
 			break;
 

src/backend/optimizer/util/clauses.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.68 2000/05/30 00:49:49 momjian Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/clauses.c,v 1.69 2000/07/12 02:37:11 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -30,6 +30,7 @@
 #include "optimizer/var.h"
 #include "parser/parse_type.h"
 #include "parser/parsetree.h"
+#include "utils/datum.h"
 #include "utils/lsyscache.h"
 #include "utils/syscache.h"
 
@@ -1317,7 +1318,10 @@ simplify_op_or_func(Expr *expr, List *args)
 	HeapTuple	func_tuple;
 	Form_pg_proc funcform;
 	Type		resultType;
+	bool		resultTypByVal;
+	int			resultTypLen;
 	Expr	   *newexpr;
+	ExprContext *econtext;
 	Datum		const_val;
 	bool		has_nonconst_input = false;
 	bool		has_null_input = false;
@@ -1424,25 +1428,35 @@ simplify_op_or_func(Expr *expr, List *args)
 	newexpr->oper = expr->oper;
 	newexpr->args = args;
 
+	/* Get info needed about result datatype */
+	resultType = typeidType(result_typeid);
+	resultTypByVal = typeByVal(resultType);
+	resultTypLen = typeLen(resultType);
+
 	/*
-	 * It is OK to pass econtext = NULL because none of the ExecEvalExpr()
+	 * It is OK to pass a dummy econtext because none of the ExecEvalExpr()
 	 * code used in this situation will use econtext.  That might seem
 	 * fortuitous, but it's not so unreasonable --- a constant expression
 	 * does not depend on context, by definition, n'est ce pas?
 	 */
-	const_val = ExecEvalExpr((Node *) newexpr, NULL,
-							 &const_is_null, &isDone);
+	econtext = MakeExprContext(NULL, CurrentMemoryContext);
+
+	const_val = ExecEvalExprSwitchContext((Node *) newexpr, econtext,
+										  &const_is_null, &isDone);
 	Assert(isDone);				/* if this isn't set, we blew it... */
+
+	/* Must copy result out of sub-context used by expression eval */
+	const_val = datumCopy(const_val, resultTypByVal, resultTypLen);
+
+	FreeExprContext(econtext);
 	pfree(newexpr);
 
 	/*
 	 * Make the constant result node.
 	 */
-	resultType = typeidType(result_typeid);
-	return (Expr *) makeConst(result_typeid, typeLen(resultType),
+	return (Expr *) makeConst(result_typeid, resultTypLen,
 							  const_val, const_is_null,
-							  typeByVal(resultType),
-							  false, false);
+							  resultTypByVal, false, false);
 }