4 files changed, 20 insertions, 40 deletions
diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h
index 31881976bd..11e31e0a65 100644
--- a/src/include/nodes/nodes.h
+++ b/src/include/nodes/nodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.220 2009/02/02 19:31:40 alvherre Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/nodes.h,v 1.221 2009/02/25 03:30:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -216,7 +216,6 @@ typedef enum NodeTag
 	T_PathKey,
 	T_RestrictInfo,
 	T_InnerIndexscanInfo,
-	T_FlattenedSubLink,
 	T_PlaceHolderVar,
 	T_SpecialJoinInfo,
 	T_AppendRelInfo,
diff --git a/src/include/nodes/primnodes.h b/src/include/nodes/primnodes.h
index 0d8efbe988..3315329923 100644
--- a/src/include/nodes/primnodes.h
+++ b/src/include/nodes/primnodes.h
@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.145 2009/01/01 17:24:00 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/primnodes.h,v 1.146 2009/02/25 03:30:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1137,7 +1137,9 @@ typedef struct RangeTblRef
  *
  * During parse analysis, an RTE is created for the Join, and its index
  * is filled into rtindex.	This RTE is present mainly so that Vars can
- * be created that refer to the outputs of the join.
+ * be created that refer to the outputs of the join.  The planner sometimes
+ * generates JoinExprs internally; these can have rtindex = 0 if there are
+ * no join alias variables referencing such joins.
  *----------
  */
 typedef struct JoinExpr
@@ -1150,7 +1152,7 @@ typedef struct JoinExpr
 	List	   *using;			/* USING clause, if any (list of String) */
 	Node	   *quals;			/* qualifiers on join, if any */
 	Alias	   *alias;			/* user-written alias clause, if any */
-	int			rtindex;		/* RT index assigned for join */
+	int			rtindex;		/* RT index assigned for join, or 0 */
 } JoinExpr;
 
 /*----------
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index f00d1becc7..e8e20d202b 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.168 2009/02/06 23:43:24 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.169 2009/02/25 03:30:37 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1076,30 +1076,6 @@ typedef struct InnerIndexscanInfo
 } InnerIndexscanInfo;
 
 /*
- * "Flattened SubLinks"
- *
- * When we pull an IN or EXISTS SubLink up into the parent query, the
- * join conditions extracted from the IN/EXISTS clause need to be specially
- * treated in distribute_qual_to_rels processing.  We handle this by
- * wrapping such expressions in a FlattenedSubLink node that identifies
- * the join they come from.  The FlattenedSubLink node is discarded after
- * distribute_qual_to_rels, having served its purpose.
- *
- * Although the planner treats this as an expression node type, it is not
- * recognized by the parser or executor, so we declare it here rather than
- * in primnodes.h.
- */
-
-typedef struct FlattenedSubLink
-{
-	Expr		xpr;
-	JoinType	jointype;		/* must be JOIN_SEMI or JOIN_ANTI */
-	Relids		lefthand;		/* base relids treated as syntactic LHS */
-	Relids		righthand;		/* base relids syntactically within RHS */
-	Expr	   *quals;			/* join quals (in explicit-AND format) */
-} FlattenedSubLink;
-
-/*
  * Placeholder node for an expression to be evaluated below the top level
  * of a plan tree.  This is used during planning to represent the contained
  * expression.  At the end of the planning process it is replaced by either
@@ -1171,8 +1147,11 @@ typedef struct PlaceHolderVar
  * For purposes of join selectivity estimation, we create transient
  * SpecialJoinInfo structures for regular inner joins; so it is possible
  * to have jointype == JOIN_INNER in such a structure, even though this is
- * not allowed within join_info_list.  Note that lhs_strict, delay_upper_joins,
- * and join_quals are not set meaningfully for such structs.
+ * not allowed within join_info_list.  We also create transient
+ * SpecialJoinInfos with jointype == JOIN_INNER for outer joins, since for
+ * cost estimation purposes it is sometimes useful to know the join size under
+ * plain innerjoin semantics.  Note that lhs_strict, delay_upper_joins, and
+ * join_quals are not set meaningfully within such structs.
  */
 
 typedef struct SpecialJoinInfo
diff --git a/src/include/optimizer/subselect.h b/src/include/optimizer/subselect.h
index 54965a5fe7..a318853596 100644
--- a/src/include/optimizer/subselect.h
+++ b/src/include/optimizer/subselect.h
@@ -5,7 +5,7 @@
  * Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/optimizer/subselect.h,v 1.35 2009/01/01 17:24:00 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/optimizer/subselect.h,v 1.36 2009/02/25 03:30:38 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -16,13 +16,13 @@
 #include "nodes/relation.h"
 
 extern void SS_process_ctes(PlannerInfo *root);
-extern bool convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
-										Relids available_rels,
-										Node **new_qual, List **fromlist);
-extern bool convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
-										   bool under_not,
-										   Relids available_rels,
-										   Node **new_qual, List **fromlist);
+extern JoinExpr *convert_ANY_sublink_to_join(PlannerInfo *root,
+											 SubLink *sublink,
+											 Relids available_rels);
+extern JoinExpr *convert_EXISTS_sublink_to_join(PlannerInfo *root,
+												SubLink *sublink,
+												bool under_not,
+												Relids available_rels);
 extern Node *SS_replace_correlation_vars(PlannerInfo *root, Node *expr);
 extern Node *SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual);
 extern void SS_finalize_plan(PlannerInfo *root, Plan *plan,