Second try at fixing join alias variables. Instead of attaching miscellaneous

lists to join RTEs, attach a list of Vars and COALESCE expressions that will
replace the join's alias variables during planning.  This simplifies
flatten_join_alias_vars while still making it easy to fix up varno references
when transforming the query tree.  Add regression test cases for interactions
of subqueries with outer joins.

6 files changed, 16 insertions, 28 deletions

diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 6ebe79cc6a3..e135782bd58 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -37,7 +37,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: catversion.h,v 1.128 2002/04/27 21:24:34 tgl Exp $
+ * $Id: catversion.h,v 1.129 2002/04/28 19:54:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	200204271
+#define CATALOG_VERSION_NO	200204281
 
 #endif
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index 60703a06dcc..5bd0e89b185 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parsenodes.h,v 1.174 2002/04/24 02:48:55 momjian Exp $
+ * $Id: parsenodes.h,v 1.175 2002/04/28 19:54:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -510,17 +510,14 @@ typedef struct RangeTblEntry
 	/*
 	 * Fields valid for a join RTE (else NULL/zero):
 	 *
-	 * joincoltypes/joincoltypmods identify the column datatypes of the
-	 * join result.  joinleftcols and joinrightcols identify the source
-	 * columns from the join's inputs: each entry is either a source column
-	 * AttrNumber or zero.  For normal columns exactly one is nonzero,
-	 * but both are nonzero for a column "merged" by USING or NATURAL.
+	 * joinaliasvars is a list of Vars or COALESCE expressions corresponding
+	 * to the columns of the join result.  An alias Var referencing column
+	 * K of the join result can be replaced by the K'th element of
+	 * joinaliasvars --- but to simplify the task of reverse-listing aliases
+	 * correctly, we do not do that until planning time.
 	 */
 	JoinType	jointype;		/* type of join */
-	List	   *joincoltypes;	/* integer list of column type OIDs */
-	List	   *joincoltypmods;	/* integer list of column typmods */
-	List	   *joinleftcols;	/* integer list of left-side column #s */
-	List	   *joinrightcols;	/* integer list of right-side column #s */
+	List	   *joinaliasvars;	/* list of alias-var expansions */
 
 	/*
 	 * Fields valid in all RTEs:
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 66db9cf3640..9ba1caca327 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: plannodes.h,v 1.54 2002/03/12 00:52:01 tgl Exp $
+ * $Id: plannodes.h,v 1.55 2002/04/28 19:54:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -254,7 +254,6 @@ typedef struct SubqueryScan
  * jointype:	rule for joining tuples from left and right subtrees
  * joinqual:	qual conditions that came from JOIN/ON or JOIN/USING
  *				(plan.qual contains conditions that came from WHERE)
- * joinrti:		rtable index of corresponding JOIN RTE, if any (0 if none)
  *
  * When jointype is INNER, joinqual and plan.qual are semantically
  * interchangeable.  For OUTER jointypes, the two are *not* interchangeable;
@@ -263,8 +262,6 @@ typedef struct SubqueryScan
  * (But plan.qual is still applied before actually returning a tuple.)
  * For an outer join, only joinquals are allowed to be used as the merge
  * or hash condition of a merge or hash join.
- *
- * joinrti is for the convenience of setrefs.c; it's not used in execution.
  * ----------------
  */
 typedef struct Join
@@ -272,7 +269,6 @@ typedef struct Join
 	Plan		plan;
 	JoinType	jointype;
 	List	   *joinqual;		/* JOIN quals (in addition to plan.qual) */
-	Index		joinrti;		/* JOIN RTE, if any */
 } Join;
 
 /* ----------------
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 919f3d23de4..3956555a2e0 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: planmain.h,v 1.55 2002/03/12 00:52:03 tgl Exp $
+ * $Id: planmain.h,v 1.56 2002/04/28 19:54:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -59,7 +59,7 @@ extern void process_implied_equality(Query *root, Node *item1, Node *item2,
 extern void set_plan_references(Query *root, Plan *plan);
 extern List *join_references(List *clauses, Query *root,
 							 List *outer_tlist, List *inner_tlist,
-							 Index acceptable_rel, Index join_rti);
+							 Index acceptable_rel);
 extern void fix_opids(Node *node);
 
 /*
diff --git a/src/include/optimizer/var.h b/src/include/optimizer/var.h
index 1153604e48a..c9a22b8f55a 100644
--- a/src/include/optimizer/var.h
+++ b/src/include/optimizer/var.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: var.h,v 1.18 2002/03/12 00:52:04 tgl Exp $
+ * $Id: var.h,v 1.19 2002/04/28 19:54:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -23,8 +23,6 @@ extern bool contain_var_reference(Node *node, int varno, int varattno,
 extern bool contain_whole_tuple_var(Node *node, int varno, int levelsup);
 extern bool contain_var_clause(Node *node);
 extern List *pull_var_clause(Node *node, bool includeUpperVars);
-extern Node *flatten_join_alias_vars(Node *node, Query *root, int expandRTI);
-extern void build_join_alias_subvars(Query *root, Var *aliasvar,
-									 Var **leftsubvar, Var **rightsubvar);
+extern Node *flatten_join_alias_vars(Node *node, Query *root, bool force);
 
 #endif   /* VAR_H */
diff --git a/src/include/parser/parse_relation.h b/src/include/parser/parse_relation.h
index 038931d9b6d..353ce8957c7 100644
--- a/src/include/parser/parse_relation.h
+++ b/src/include/parser/parse_relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $Id: parse_relation.h,v 1.31 2002/03/22 02:56:37 tgl Exp $
+ * $Id: parse_relation.h,v 1.32 2002/04/28 19:54:29 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -44,10 +44,7 @@ extern RangeTblEntry *addRangeTableEntryForSubquery(ParseState *pstate,
 extern RangeTblEntry *addRangeTableEntryForJoin(ParseState *pstate,
 						  List *colnames,
 						  JoinType jointype,
-						  List *coltypes,
-						  List *coltypmods,
-						  List *leftcols,
-						  List *rightcols,
+						  List *aliasvars,
 						  Alias *alias,
 						  bool inFromCl);
 extern void addRTEtoQuery(ParseState *pstate, RangeTblEntry *rte,