Add a paramtypmod field to Param nodes. This is dead weight for Params

representing externally-supplied values, since the APIs that carry such
values only specify type not typmod.  However, for PARAM_SUBLINK Params
it is handy to carry the typmod of the sublink's output column.  This
is a much cleaner solution for the recently reported 'could not find
pathkey item to sort' and 'failed to find unique expression in subplan
tlist' bugs than my original 8.2-compatible patch.  Besides, someday we
might want to support typmods for external parameters ...

1 files changed, 13 insertions, 35 deletions

diff --git a/src/backend/optimizer/plan/subselect.c b/src/backend/optimizer/plan/subselect.c
index 72b986002d..7793d071cd 100644
--- a/src/backend/optimizer/plan/subselect.c
+++ b/src/backend/optimizer/plan/subselect.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.113 2006/12/06 19:40:01 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/subselect.c,v 1.114 2006/12/10 22:13:26 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -75,7 +75,6 @@ typedef struct convert_testexpr_context
 {
 	int			rtindex;		/* RT index for Vars, or 0 for Params */
 	List	   *righthandIds;	/* accumulated list of Vars or Param IDs */
-	List	   *sub_tlist;		/* subselect targetlist (if given) */
 } convert_testexpr_context;
 
 typedef struct finalize_primnode_context
@@ -87,8 +86,7 @@ typedef struct finalize_primnode_context
 
 static Node *convert_testexpr(Node *testexpr,
 				 int rtindex,
-				 List **righthandIds,
-				 List *sub_tlist);
+				 List **righthandIds);
 static Node *convert_testexpr_mutator(Node *node,
 						 convert_testexpr_context *context);
 static bool subplan_is_hashable(SubLink *slink, SubPlan *node);
@@ -166,6 +164,7 @@ replace_outer_var(Var *var)
 	retval->paramkind = PARAM_EXEC;
 	retval->paramid = i;
 	retval->paramtype = var->vartype;
+	retval->paramtypmod = var->vartypmod;
 
 	return retval;
 }
@@ -204,6 +203,7 @@ replace_outer_agg(Aggref *agg)
 	retval->paramkind = PARAM_EXEC;
 	retval->paramid = i;
 	retval->paramtype = agg->aggtype;
+	retval->paramtypmod = -1;
 
 	return retval;
 }
@@ -212,8 +212,6 @@ replace_outer_agg(Aggref *agg)
  * Generate a new Param node that will not conflict with any other.
  *
  * This is used to allocate PARAM_EXEC slots for subplan outputs.
- *
- * paramtypmod is currently unused but might be wanted someday.
  */
 static Param *
 generate_new_param(Oid paramtype, int32 paramtypmod)
@@ -225,6 +223,7 @@ generate_new_param(Oid paramtype, int32 paramtypmod)
 	retval->paramkind = PARAM_EXEC;
 	retval->paramid = list_length(PlannerParamList);
 	retval->paramtype = paramtype;
+	retval->paramtypmod = paramtypmod;
 
 	pitem = (PlannerParamItem *) palloc(sizeof(PlannerParamItem));
 	pitem->item = (Node *) retval;
@@ -371,7 +370,7 @@ make_subplan(SubLink *slink, Node *testexpr, bool isTopQual)
 		if (!OidIsValid(arraytype))
 			elog(ERROR, "could not find array type for datatype %s",
 				 format_type_be(exprType((Node *) te->expr)));
-		prm = generate_new_param(arraytype, -1);
+		prm = generate_new_param(arraytype, exprTypmod((Node *) te->expr));
 		node->setParam = list_make1_int(prm->paramid);
 		PlannerInitPlan = lappend(PlannerInitPlan, node);
 		result = (Node *) prm;
@@ -381,8 +380,7 @@ make_subplan(SubLink *slink, Node *testexpr, bool isTopQual)
 		/* Adjust the Params */
 		result = convert_testexpr(testexpr,
 								  0,
-								  &node->paramIds,
-								  NIL);
+								  &node->paramIds);
 		node->setParam = list_copy(node->paramIds);
 		PlannerInitPlan = lappend(PlannerInitPlan, node);
 
@@ -399,8 +397,7 @@ make_subplan(SubLink *slink, Node *testexpr, bool isTopQual)
 		/* Adjust the Params */
 		node->testexpr = convert_testexpr(testexpr,
 										  0,
-										  &node->paramIds,
-										  NIL);
+										  &node->paramIds);
 
 		/*
 		 * We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
@@ -474,10 +471,6 @@ make_subplan(SubLink *slink, Node *testexpr, bool isTopQual)
  * of the Var nodes are returned in *righthandIds (this is a bit of a type
  * cheat, but we can get away with it).
  *
- * The subquery targetlist need be supplied only if rtindex is not 0.
- * We consult it to extract the correct typmods for the created Vars.
- * (XXX this is a kluge that could go away if Params carried typmod.)
- *
  * The given testexpr has already been recursively processed by
  * process_sublinks_mutator.  Hence it can no longer contain any
  * PARAM_SUBLINK Params for lower SubLink nodes; we can safely assume that
@@ -486,15 +479,13 @@ make_subplan(SubLink *slink, Node *testexpr, bool isTopQual)
 static Node *
 convert_testexpr(Node *testexpr,
 				 int rtindex,
-				 List **righthandIds,
-				 List *sub_tlist)
+				 List **righthandIds)
 {
 	Node	   *result;
 	convert_testexpr_context context;
 
 	context.rtindex = rtindex;
 	context.righthandIds = NIL;
-	context.sub_tlist = sub_tlist;
 	result = convert_testexpr_mutator(testexpr, &context);
 	*righthandIds = context.righthandIds;
 	return result;
@@ -526,23 +517,10 @@ convert_testexpr_mutator(Node *node,
 				/* Make the Var node representing the subplan's result */
 				Var		   *newvar;
 
-				/*
-				 * XXX kluge: since Params don't carry typmod, we have to
-				 * look into the subquery targetlist to find out the right
-				 * typmod to assign to the Var.
-				 */
-				TargetEntry *ste = get_tle_by_resno(context->sub_tlist,
-													param->paramid);
-
-				if (ste == NULL || ste->resjunk)
-					elog(ERROR, "subquery output %d not found",
-						 param->paramid);
-				Assert(param->paramtype == exprType((Node *) ste->expr));
-
 				newvar = makeVar(context->rtindex,
 								 param->paramid,
 								 param->paramtype,
-								 exprTypmod((Node *) ste->expr),
+								 param->paramtypmod,
 								 0);
 
 				/*
@@ -558,7 +536,8 @@ convert_testexpr_mutator(Node *node,
 				/* Make the Param node representing the subplan's result */
 				Param	   *newparam;
 
-				newparam = generate_new_param(param->paramtype, -1);
+				newparam = generate_new_param(param->paramtype,
+											  param->paramtypmod);
 				/* Record its ID */
 				context->righthandIds = lappend_int(context->righthandIds,
 													newparam->paramid);
@@ -775,8 +754,7 @@ convert_IN_to_join(PlannerInfo *root, SubLink *sublink)
 	 */
 	return convert_testexpr(sublink->testexpr,
 							rtindex,
-							&ininfo->sub_targetlist,
-							subselect->targetList);
+							&ininfo->sub_targetlist);
 }
 
 /*