diff --git a/src/backend/optimizer/path/allpaths.c b/src/backend/optimizer/path/allpaths.c
index 00e8d6f13f..ef0b25bf5e 100644
--- a/src/backend/optimizer/path/allpaths.c
+++ b/src/backend/optimizer/path/allpaths.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.167 2008/01/01 19:45:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.168 2008/01/11 04:02:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -674,7 +674,12 @@ make_rel_from_joinlist(PlannerInfo *root, List *joinlist)
 		/*
 		 * Consider the different orders in which we could join the rels,
 		 * using a plugin, GEQO, or the regular join search code.
+		 *
+		 * We put the initial_rels list into a PlannerInfo field because
+		 * has_legal_joinclause() needs to look at it (ugly :-().
 		 */
+		root->initial_rels = initial_rels;
+
 		if (join_search_hook)
 			return (*join_search_hook) (root, levels_needed, initial_rels);
 		else if (enable_geqo && levels_needed >= geqo_threshold)
diff --git a/src/backend/optimizer/path/joinrels.c b/src/backend/optimizer/path/joinrels.c
index 1287037c0b..8df5c21f1f 100644
--- a/src/backend/optimizer/path/joinrels.c
+++ b/src/backend/optimizer/path/joinrels.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.90 2008/01/01 19:45:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/path/joinrels.c,v 1.91 2008/01/11 04:02:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -838,33 +838,27 @@ has_join_restriction(PlannerInfo *root, RelOptInfo *rel)
  *		Detect whether the specified relation can legally be joined
  *		to any other rels using join clauses.
  *
- * We consider only joins to single other relations.  This is sufficient
- * to get a "true" result in most real queries, and an occasional erroneous
- * "false" will only cost a bit more planning time.  The reason for this
- * limitation is that considering joins to other joins would require proving
- * that the other join rel can legally be formed, which seems like too much
- * trouble for something that's only a heuristic to save planning time.
+ * We consider only joins to single other relations in the current
+ * initial_rels list.  This is sufficient to get a "true" result in most real
+ * queries, and an occasional erroneous "false" will only cost a bit more
+ * planning time.  The reason for this limitation is that considering joins to
+ * other joins would require proving that the other join rel can legally be
+ * formed, which seems like too much trouble for something that's only a
+ * heuristic to save planning time.  (Note: we must look at initial_rels
+ * and not all of the query, since when we are planning a sub-joinlist we
+ * may be forced to make clauseless joins within initial_rels even though
+ * there are join clauses linking to other parts of the query.)
  */
 static bool
 has_legal_joinclause(PlannerInfo *root, RelOptInfo *rel)
 {
-	Index		rti;
+	ListCell   *lc;
 
-	for (rti = 1; rti < root->simple_rel_array_size; rti++)
+	foreach(lc, root->initial_rels)
 	{
-		RelOptInfo *rel2 = root->simple_rel_array[rti];
+		RelOptInfo *rel2 = (RelOptInfo *) lfirst(lc);
 
-		/* there may be empty slots corresponding to non-baserel RTEs */
-		if (rel2 == NULL)
-			continue;
-
-		Assert(rel2->relid == rti);		/* sanity check on array */
-
-		/* ignore RTEs that are "other rels" */
-		if (rel2->reloptkind != RELOPT_BASEREL)
-			continue;
-
-		/* ignore RTEs that are already in "rel" */
+		/* ignore rels that are already in "rel" */
 		if (bms_overlap(rel->relids, rel2->relids))
 			continue;
 
diff --git a/src/backend/optimizer/plan/planmain.c b/src/backend/optimizer/plan/planmain.c
index 9edd552138..3776cf9b34 100644
--- a/src/backend/optimizer/plan/planmain.c
+++ b/src/backend/optimizer/plan/planmain.c
@@ -14,7 +14,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.105 2008/01/01 19:45:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.106 2008/01/11 04:02:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -142,6 +142,7 @@ query_planner(PlannerInfo *root, List *tlist,
 	root->right_join_clauses = NIL;
 	root->full_join_clauses = NIL;
 	root->oj_info_list = NIL;
+	root->initial_rels = NIL;
 
 	/*
 	 * Make a flattened version of the rangetable for faster access (this is
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index f01f1e9e51..b106c590e3 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.153 2008/01/09 20:42:28 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.154 2008/01/11 04:02:18 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -165,6 +165,8 @@ typedef struct PlannerInfo
 	List	   *group_pathkeys; /* groupClause pathkeys, if any */
 	List	   *sort_pathkeys;	/* sortClause pathkeys, if any */
 
+	List	   *initial_rels;	/* RelOptInfos we are now trying to join */
+
 	MemoryContext planner_cxt;	/* context holding PlannerInfo */
 
 	double		total_table_pages;		/* # of pages in all tables of query */