revert-a3179ab69-doesnt-work.patch

diff --git a/src/backend/optimizer/path/equivclass.c b/src/backend/optimizer/path/equivclass.c
index 441f12f6c50..54e0b5cbdd1 100644
--- a/src/backend/optimizer/path/equivclass.c
+++ b/src/backend/optimizer/path/equivclass.c
@@ -1453,8 +1453,7 @@ generate_base_implied_equalities_no_const(PlannerInfo *root,
 	 * For the moment we force all the Vars to be available at all join nodes
 	 * for this eclass.  Perhaps this could be improved by doing some
 	 * pre-analysis of which members we prefer to join, but it's no worse than
-	 * what happened in the pre-8.3 code.  (Note: rebuild_eclass_attr_needed
-	 * needs to match this code.)
+	 * what happened in the pre-8.3 code.
 	 */
 	foreach(lc, ec->ec_members)
 	{
@@ -2561,51 +2560,6 @@ reconsider_full_join_clause(PlannerInfo *root, OuterJoinClauseInfo *ojcinfo)
 	return false;				/* failed to make any deduction */
 }
 
-/*
- * rebuild_eclass_attr_needed
- *	  Put back attr_needed bits for Vars/PHVs needed for join eclasses.
- *
- * This is used to rebuild attr_needed/ph_needed sets after removal of a
- * useless outer join.  It should match what
- * generate_base_implied_equalities_no_const did, except that we call
- * add_vars_to_attr_needed not add_vars_to_targetlist.
- */
-void
-rebuild_eclass_attr_needed(PlannerInfo *root)
-{
-	ListCell   *lc;
-
-	foreach(lc, root->eq_classes)
-	{
-		EquivalenceClass *ec = (EquivalenceClass *) lfirst(lc);
-
-		/*
-		 * We don't expect any EC child members to exist at this point. Ensure
-		 * that's the case, otherwise, we might be getting asked to do
-		 * something this function hasn't been coded for.
-		 */
-		Assert(ec->ec_childmembers == NULL);
-
-		/* Need do anything only for a multi-member, no-const EC. */
-		if (list_length(ec->ec_members) > 1 && !ec->ec_has_const)
-		{
-			ListCell   *lc2;
-
-			foreach(lc2, ec->ec_members)
-			{
-				EquivalenceMember *cur_em = (EquivalenceMember *) lfirst(lc2);
-				List	   *vars = pull_var_clause((Node *) cur_em->em_expr,
-												   PVC_RECURSE_AGGREGATES |
-												   PVC_RECURSE_WINDOWFUNCS |
-												   PVC_INCLUDE_PLACEHOLDERS);
-
-				add_vars_to_attr_needed(root, vars, ec->ec_relids);
-				list_free(vars);
-			}
-		}
-	}
-}
-
 /*
  * find_join_domain
  *	  Find the highest JoinDomain enclosed within the given relid set.
diff --git a/src/backend/optimizer/plan/analyzejoins.c b/src/backend/optimizer/plan/analyzejoins.c
index 4455a046d23..11ce7e33573 100644
--- a/src/backend/optimizer/plan/analyzejoins.c
+++ b/src/backend/optimizer/plan/analyzejoins.c
@@ -28,7 +28,6 @@
 #include "optimizer/optimizer.h"
 #include "optimizer/pathnode.h"
 #include "optimizer/paths.h"
-#include "optimizer/placeholder.h"
 #include "optimizer/planmain.h"
 #include "optimizer/restrictinfo.h"
 #include "rewrite/rewriteManip.h"
@@ -344,6 +343,37 @@ remove_rel_from_query(PlannerInfo *root, RelOptInfo *rel,
 											  sjinfo->ojrelid);
 	}
 
+	/*
+	 * Remove references to the rel from other baserels' attr_needed arrays.
+	 */
+	for (rti = 1; rti < root->simple_rel_array_size; rti++)
+	{
+		RelOptInfo *otherrel = root->simple_rel_array[rti];
+		int			attroff;
+
+		/* there may be empty slots corresponding to non-baserel RTEs */
+		if (otherrel == NULL)
+			continue;
+
+		Assert(otherrel->relid == rti); /* sanity check on array */
+
+		/* no point in processing target rel itself */
+		if (otherrel == rel)
+			continue;
+
+		for (attroff = otherrel->max_attr - otherrel->min_attr;
+			 attroff >= 0;
+			 attroff--)
+		{
+			otherrel->attr_needed[attroff] =
+				bms_del_member(otherrel->attr_needed[attroff], relid);
+			if (sjinfo != NULL)
+				otherrel->attr_needed[attroff] =
+					bms_del_member(otherrel->attr_needed[attroff],
+								   sjinfo->ojrelid);
+		}
+	}
+
 	/*
 	 * Likewise remove references from SpecialJoinInfo data structures.
 	 *
@@ -451,11 +481,13 @@ remove_rel_from_query(PlannerInfo *root, RelOptInfo *rel,
 				phinfo->ph_eval_at = adjust_relid_set(phinfo->ph_eval_at,
 													  sjinfo->ojrelid, subst);
 			Assert(!bms_is_empty(phinfo->ph_eval_at));	/* checked previously */
-			/* Reduce ph_needed to contain only "relation 0"; see below */
-			if (bms_is_member(0, phinfo->ph_needed))
-				phinfo->ph_needed = bms_make_singleton(0);
-			else
-				phinfo->ph_needed = NULL;
+
+			phinfo->ph_needed = adjust_relid_set(phinfo->ph_needed,
+												 relid, subst);
+			if (sjinfo != NULL)
+				phinfo->ph_needed = adjust_relid_set(phinfo->ph_needed,
+													 sjinfo->ojrelid, subst);
+			/* ph_needed might or might not become empty */
 
 			phinfo->ph_lateral = adjust_relid_set(phinfo->ph_lateral, relid, subst);
 
@@ -490,46 +522,6 @@ remove_rel_from_query(PlannerInfo *root, RelOptInfo *rel,
 			(sjinfo == NULL || bms_is_member(sjinfo->ojrelid, ec->ec_relids)))
 			remove_rel_from_eclass(ec, sjinfo, relid, subst);
 	}
-
-	/*
-	 * Finally, we must recompute per-Var attr_needed and per-PlaceHolderVar
-	 * ph_needed relid sets.  These have to be known accurately, else we may
-	 * fail to remove other now-removable outer joins.  And our removal of the
-	 * join clause(s) for this outer join may mean that Vars that were
-	 * formerly needed no longer are.  So we have to do this honestly by
-	 * repeating the construction of those relid sets.  We can cheat to one
-	 * small extent: we can avoid re-examining the targetlist and HAVING qual
-	 * by preserving "relation 0" bits from the existing relid sets.  This is
-	 * safe because we'd never remove such references.
-	 *
-	 * So, start by removing all other bits from attr_needed sets and
-	 * lateral_vars lists.  (We already did this above for ph_needed.)
-	 */
-	for (rti = 1; rti < root->simple_rel_array_size; rti++)
-	{
-		RelOptInfo *otherrel = root->simple_rel_array[rti];
-		int			attroff;
-
-		/* there may be empty slots corresponding to non-baserel RTEs */
-		if (otherrel == NULL)
-			continue;
-
-		Assert(otherrel->relid == rti); /* sanity check on array */
-
-		for (attroff = otherrel->max_attr - otherrel->min_attr;
-			 attroff >= 0;
-			 attroff--)
-		{
-			if (bms_is_member(0, otherrel->attr_needed[attroff]))
-				otherrel->attr_needed[attroff] = bms_make_singleton(0);
-			else
-				otherrel->attr_needed[attroff] = NULL;
-		}
-
-		if (subst > 0)
-			ChangeVarNodesExtended((Node *) otherrel->lateral_vars, relid,
-								   subst, 0, replace_relid_callback);
-	}
 }
 
 /*
@@ -626,7 +618,7 @@ remove_leftjoinrel_from_query(PlannerInfo *root, int relid,
 	 */
 
 	/*
-	 * Now remove the rel from the baserel array to prevent it from being
+	 * Finally, remove the rel from the baserel array to prevent it from being
 	 * referenced again.  (We can't do this earlier because
 	 * remove_join_clause_from_rels will touch it.)
 	 */
@@ -635,15 +627,6 @@ remove_leftjoinrel_from_query(PlannerInfo *root, int relid,
 
 	/* And nuke the RelOptInfo, just in case there's another access path */
 	pfree(rel);
-
-	/*
-	 * Now repeat construction of attr_needed bits coming from all other
-	 * sources.
-	 */
-	rebuild_placeholder_attr_needed(root);
-	rebuild_joinclause_attr_needed(root);
-	rebuild_eclass_attr_needed(root);
-	rebuild_lateral_attr_needed(root);
 }
 
 /*
@@ -1984,16 +1967,6 @@ remove_self_join_rel(PlannerInfo *root, PlanRowMark *kmark, PlanRowMark *rmark,
 
 	/* And nuke the RelOptInfo, just in case there's another access path. */
 	pfree(toRemove);
-
-
-	/*
-	 * Now repeat construction of attr_needed bits coming from all other
-	 * sources.
-	 */
-	rebuild_placeholder_attr_needed(root);
-	rebuild_joinclause_attr_needed(root);
-	rebuild_eclass_attr_needed(root);
-	rebuild_lateral_attr_needed(root);
 }
 
 /*
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index 01804b085b3..0ed6feb8cdd 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -275,8 +275,6 @@ build_base_rel_tlists(PlannerInfo *root, List *final_tlist)
  *	  have a single owning relation; we keep their attr_needed info in
  *	  root->placeholder_list instead.  Find or create the associated
  *	  PlaceHolderInfo entry, and update its ph_needed.
- *
- *	  See also add_vars_to_attr_needed.
  */
 void
 add_vars_to_targetlist(PlannerInfo *root, List *vars,
@@ -330,62 +328,6 @@ add_vars_to_targetlist(PlannerInfo *root, List *vars,
 	}
 }
 
-/*
- * add_vars_to_attr_needed
- *	  This does a subset of what add_vars_to_targetlist does: it just
- *	  updates attr_needed for Vars and ph_needed for PlaceHolderVars.
- *	  We assume the Vars are already in their relations' targetlists.
- *
- *	  This is used to rebuild attr_needed/ph_needed sets after removal
- *	  of a useless outer join.  The removed join clause might have been
- *	  the only upper-level use of some other relation's Var, in which
- *	  case we can reduce that Var's attr_needed and thereby possibly
- *	  open the door to further join removals.  But we can't tell that
- *	  without tedious reconstruction of the attr_needed data.
- *
- *	  Note that if a Var's attr_needed is successfully reduced to empty,
- *	  it will still be in the relation's targetlist even though we do
- *	  not really need the scan plan node to emit it.  The extra plan
- *	  inefficiency seems tiny enough to not be worth spending planner
- *	  cycles to get rid of it.
- */
-void
-add_vars_to_attr_needed(PlannerInfo *root, List *vars,
-						Relids where_needed)
-{
-	ListCell   *temp;
-
-	Assert(!bms_is_empty(where_needed));
-
-	foreach(temp, vars)
-	{
-		Node	   *node = (Node *) lfirst(temp);
-
-		if (IsA(node, Var))
-		{
-			Var		   *var = (Var *) node;
-			RelOptInfo *rel = find_base_rel(root, var->varno);
-			int			attno = var->varattno;
-
-			if (bms_is_subset(where_needed, rel->relids))
-				continue;
-			Assert(attno >= rel->min_attr && attno <= rel->max_attr);
-			attno -= rel->min_attr;
-			rel->attr_needed[attno] = bms_add_members(rel->attr_needed[attno],
-													  where_needed);
-		}
-		else if (IsA(node, PlaceHolderVar))
-		{
-			PlaceHolderVar *phv = (PlaceHolderVar *) node;
-			PlaceHolderInfo *phinfo = find_placeholder_info(root, phv);
-
-			phinfo->ph_needed = bms_add_members(phinfo->ph_needed,
-												where_needed);
-		}
-		else
-			elog(ERROR, "unrecognized node type: %d", (int) nodeTag(node));
-	}
-}
 
 /*****************************************************************************
  *
@@ -788,54 +730,10 @@ extract_lateral_references(PlannerInfo *root, RelOptInfo *brel, Index rtindex)
 	 */
 	add_vars_to_targetlist(root, newvars, where_needed);
 
-	/*
-	 * Remember the lateral references for rebuild_lateral_attr_needed and
-	 * create_lateral_join_info.
-	 */
+	/* Remember the lateral references for create_lateral_join_info */
 	brel->lateral_vars = newvars;
 }
 
-/*
- * rebuild_lateral_attr_needed
- *	  Put back attr_needed bits for Vars/PHVs needed for lateral references.
- *
- * This is used to rebuild attr_needed/ph_needed sets after removal of a
- * useless outer join.  It should match what find_lateral_references did,
- * except that we call add_vars_to_attr_needed not add_vars_to_targetlist.
- */
-void
-rebuild_lateral_attr_needed(PlannerInfo *root)
-{
-	Index		rti;
-
-	/* We need do nothing if the query contains no LATERAL RTEs */
-	if (!root->hasLateralRTEs)
-		return;
-
-	/* Examine the same baserels that find_lateral_references did */
-	for (rti = 1; rti < root->simple_rel_array_size; rti++)
-	{
-		RelOptInfo *brel = root->simple_rel_array[rti];
-		Relids		where_needed;
-
-		if (brel == NULL)
-			continue;
-		if (brel->reloptkind != RELOPT_BASEREL)
-			continue;
-
-		/*
-		 * We don't need to repeat all of extract_lateral_references, since it
-		 * kindly saved the extracted Vars/PHVs in lateral_vars.
-		 */
-		if (brel->lateral_vars == NIL)
-			continue;
-
-		where_needed = bms_make_singleton(rti);
-
-		add_vars_to_attr_needed(root, brel->lateral_vars, where_needed);
-	}
-}
-
 /*
  * create_lateral_join_info
  *	  Fill in the per-base-relation direct_lateral_relids, lateral_relids
@@ -2789,9 +2687,6 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 	 * var propagation is ensured by making ojscope include input rels from
 	 * both sides of the join.
 	 *
-	 * See also rebuild_joinclause_attr_needed, which has to partially repeat
-	 * this work after removal of an outer join.
-	 *
 	 * Note: if the clause gets absorbed into an EquivalenceClass then this
 	 * may be unnecessary, but for now we have to do it to cover the case
 	 * where the EC becomes ec_broken and we end up reinserting the original
@@ -3401,11 +3296,6 @@ process_implied_equality(PlannerInfo *root,
 	 * some of the Vars could have missed having that done because they only
 	 * appeared in single-relation clauses originally.  So do it here for
 	 * safety.
-	 *
-	 * See also rebuild_joinclause_attr_needed, which has to partially repeat
-	 * this work after removal of an outer join.  (Since we will put this
-	 * clause into the joininfo lists, that function needn't do any extra work
-	 * to find it.)
 	 */
 	if (bms_membership(relids) == BMS_MULTIPLE)
 	{
@@ -3547,72 +3437,6 @@ get_join_domain_min_rels(PlannerInfo *root, Relids domain_relids)
 }
 
 
-/*
- * rebuild_joinclause_attr_needed
- *	  Put back attr_needed bits for Vars/PHVs needed for join clauses.
- *
- * This is used to rebuild attr_needed/ph_needed sets after removal of a
- * useless outer join.  It should match what distribute_qual_to_rels did,
- * except that we call add_vars_to_attr_needed not add_vars_to_targetlist.
- */
-void
-rebuild_joinclause_attr_needed(PlannerInfo *root)
-{
-	/*
-	 * We must examine all join clauses, but there's no value in processing
-	 * any join clause more than once.  So it's slightly annoying that we have
-	 * to find them via the per-base-relation joininfo lists.  Avoid duplicate
-	 * processing by tracking the rinfo_serial numbers of join clauses we've
-	 * already seen.  (This doesn't work for is_clone clauses, so we must
-	 * waste effort on them.)
-	 */
-	Bitmapset  *seen_serials = NULL;
-	Index		rti;
-
-	/* Scan all baserels for join clauses */
-	for (rti = 1; rti < root->simple_rel_array_size; rti++)
-	{
-		RelOptInfo *brel = root->simple_rel_array[rti];
-		ListCell   *lc;
-
-		if (brel == NULL)
-			continue;
-		if (brel->reloptkind != RELOPT_BASEREL)
-			continue;
-
-		foreach(lc, brel->joininfo)
-		{
-			RestrictInfo *rinfo = (RestrictInfo *) lfirst(lc);
-			Relids		relids = rinfo->required_relids;
-
-			if (!rinfo->is_clone)	/* else serial number is not unique */
-			{
-				if (bms_is_member(rinfo->rinfo_serial, seen_serials))
-					continue;	/* saw it already */
-				seen_serials = bms_add_member(seen_serials,
-											  rinfo->rinfo_serial);
-			}
-
-			if (bms_membership(relids) == BMS_MULTIPLE)
-			{
-				List	   *vars = pull_var_clause((Node *) rinfo->clause,
-												   PVC_RECURSE_AGGREGATES |
-												   PVC_RECURSE_WINDOWFUNCS |
-												   PVC_INCLUDE_PLACEHOLDERS);
-				Relids		where_needed;
-
-				if (rinfo->is_clone)
-					where_needed = bms_intersect(relids, root->all_baserels);
-				else
-					where_needed = relids;
-				add_vars_to_attr_needed(root, vars, where_needed);
-				list_free(vars);
-			}
-		}
-	}
-}
-
-
 /*
  * match_foreign_keys_to_quals
  *		Match foreign-key constraints to equivalence classes and join quals
diff --git a/src/backend/optimizer/util/placeholder.c b/src/backend/optimizer/util/placeholder.c
index e1cd00a72fb..d1ba8923b26 100644
--- a/src/backend/optimizer/util/placeholder.c
+++ b/src/backend/optimizer/util/placeholder.c
@@ -314,33 +314,6 @@ fix_placeholder_input_needed_levels(PlannerInfo *root)
 	}
 }
 
-/*
- * rebuild_placeholder_attr_needed
- *	  Put back attr_needed bits for Vars/PHVs needed in PlaceHolderVars.
- *
- * This is used to rebuild attr_needed/ph_needed sets after removal of a
- * useless outer join.  It should match what
- * fix_placeholder_input_needed_levels did, except that we call
- * add_vars_to_attr_needed not add_vars_to_targetlist.
- */
-void
-rebuild_placeholder_attr_needed(PlannerInfo *root)
-{
-	ListCell   *lc;
-
-	foreach(lc, root->placeholder_list)
-	{
-		PlaceHolderInfo *phinfo = (PlaceHolderInfo *) lfirst(lc);
-		List	   *vars = pull_var_clause((Node *) phinfo->ph_var->phexpr,
-										   PVC_RECURSE_AGGREGATES |
-										   PVC_RECURSE_WINDOWFUNCS |
-										   PVC_INCLUDE_PLACEHOLDERS);
-
-		add_vars_to_attr_needed(root, vars, phinfo->ph_eval_at);
-		list_free(vars);
-	}
-}
-
 /*
  * add_placeholders_to_base_rels
  *		Add any required PlaceHolderVars to base rels' targetlists.
diff --git a/src/include/optimizer/paths.h b/src/include/optimizer/paths.h
index 8410531f2d6..e0924e622d4 100644
--- a/src/include/optimizer/paths.h
+++ b/src/include/optimizer/paths.h
@@ -129,7 +129,6 @@ extern bool process_equivalence(PlannerInfo *root,
 extern Expr *canonicalize_ec_expression(Expr *expr,
 										Oid req_type, Oid req_collation);
 extern void reconsider_outer_join_clauses(PlannerInfo *root);
-extern void rebuild_eclass_attr_needed(PlannerInfo *root);
 extern EquivalenceClass *get_eclass_for_sort_expr(PlannerInfo *root,
 												  Expr *expr,
 												  List *opfamilies,
diff --git a/src/include/optimizer/placeholder.h b/src/include/optimizer/placeholder.h
index db92d8861ba..a729e73d561 100644
--- a/src/include/optimizer/placeholder.h
+++ b/src/include/optimizer/placeholder.h
@@ -23,7 +23,6 @@ extern PlaceHolderInfo *find_placeholder_info(PlannerInfo *root,
 											  PlaceHolderVar *phv);
 extern void find_placeholders_in_jointree(PlannerInfo *root);
 extern void fix_placeholder_input_needed_levels(PlannerInfo *root);
-extern void rebuild_placeholder_attr_needed(PlannerInfo *root);
 extern void add_placeholders_to_base_rels(PlannerInfo *root);
 extern void add_placeholders_to_joinrel(PlannerInfo *root, RelOptInfo *joinrel,
 										RelOptInfo *outer_rel, RelOptInfo *inner_rel,
diff --git a/src/include/optimizer/planmain.h b/src/include/optimizer/planmain.h
index 9d3debcab28..e3bf9db6b6e 100644
--- a/src/include/optimizer/planmain.h
+++ b/src/include/optimizer/planmain.h
@@ -73,11 +73,8 @@ extern void add_other_rels_to_query(PlannerInfo *root);
 extern void build_base_rel_tlists(PlannerInfo *root, List *final_tlist);
 extern void add_vars_to_targetlist(PlannerInfo *root, List *vars,
 								   Relids where_needed);
-extern void add_vars_to_attr_needed(PlannerInfo *root, List *vars,
-									Relids where_needed);
 extern void remove_useless_groupby_columns(PlannerInfo *root);
 extern void find_lateral_references(PlannerInfo *root);
-extern void rebuild_lateral_attr_needed(PlannerInfo *root);
 extern void create_lateral_join_info(PlannerInfo *root);
 extern List *deconstruct_jointree(PlannerInfo *root);
 extern bool restriction_is_always_true(PlannerInfo *root,
@@ -101,7 +98,6 @@ extern RestrictInfo *build_implied_join_equality(PlannerInfo *root,
 												 Expr *item2,
 												 Relids qualscope,
 												 Index security_level);
-extern void rebuild_joinclause_attr_needed(PlannerInfo *root);
 extern void match_foreign_keys_to_quals(PlannerInfo *root);
 
 /*
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 390aabfb34b..336def509bc 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -5853,13 +5853,11 @@ CREATE TEMP TABLE a (id int PRIMARY KEY, b_id int);
 CREATE TEMP TABLE b (id int PRIMARY KEY, c_id int);
 CREATE TEMP TABLE c (id int PRIMARY KEY);
 CREATE TEMP TABLE d (a int, b int);
-CREATE TEMP TABLE e (id1 int, id2 int, PRIMARY KEY(id1, id2));
 INSERT INTO a VALUES (0, 0), (1, NULL);
 INSERT INTO b VALUES (0, 0), (1, NULL);
 INSERT INTO c VALUES (0), (1);
 INSERT INTO d VALUES (1,3), (2,2), (3,1);
-INSERT INTO e VALUES (0,0), (2,2), (3,1);
--- all these cases should be optimizable into a simple seqscan
+-- all three cases should be optimizable into a simple seqscan
 explain (costs off) SELECT a.* FROM a LEFT JOIN b ON a.b_id = b.id;
   QUERY PLAN   
 ---------------
@@ -5880,14 +5878,6 @@ explain (costs off)
  Seq Scan on a
 (1 row)
 
-explain (costs off)
-  SELECT a.* FROM a LEFT JOIN b ON a.id = b.id
-  LEFT JOIN e ON e.id1 = a.b_id AND b.c_id = e.id2;
-  QUERY PLAN   
----------------
- Seq Scan on a
-(1 row)
-
 -- check optimization of outer join within another special join
 explain (costs off)
 select id from a where id in (
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index f6e7070db65..2850c20eb37 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -2086,22 +2086,17 @@ CREATE TEMP TABLE a (id int PRIMARY KEY, b_id int);
 CREATE TEMP TABLE b (id int PRIMARY KEY, c_id int);
 CREATE TEMP TABLE c (id int PRIMARY KEY);
 CREATE TEMP TABLE d (a int, b int);
-CREATE TEMP TABLE e (id1 int, id2 int, PRIMARY KEY(id1, id2));
 INSERT INTO a VALUES (0, 0), (1, NULL);
 INSERT INTO b VALUES (0, 0), (1, NULL);
 INSERT INTO c VALUES (0), (1);
 INSERT INTO d VALUES (1,3), (2,2), (3,1);
-INSERT INTO e VALUES (0,0), (2,2), (3,1);
 
--- all these cases should be optimizable into a simple seqscan
+-- all three cases should be optimizable into a simple seqscan
 explain (costs off) SELECT a.* FROM a LEFT JOIN b ON a.b_id = b.id;
 explain (costs off) SELECT b.* FROM b LEFT JOIN c ON b.c_id = c.id;
 explain (costs off)
   SELECT a.* FROM a LEFT JOIN (b left join c on b.c_id = c.id)
   ON (a.b_id = b.id);
-explain (costs off)
-  SELECT a.* FROM a LEFT JOIN b ON a.id = b.id
-  LEFT JOIN e ON e.id1 = a.b_id AND b.c_id = e.id2;
 
 -- check optimization of outer join within another special join
 explain (costs off)