diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index c1858e6746d..a9cb0416c34 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -15,7 +15,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.353 2006/11/05 22:42:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.353.2.1 2007/05/22 23:24:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1318,6 +1318,7 @@ _copyOuterJoinInfo(OuterJoinInfo *from)
 	COPY_BITMAPSET_FIELD(min_righthand);
 	COPY_SCALAR_FIELD(is_full_join);
 	COPY_SCALAR_FIELD(lhs_strict);
+	COPY_SCALAR_FIELD(delay_upper_joins);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index a42afb77a3d..13be0e0f9c8 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -18,7 +18,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.287 2006/11/05 22:42:08 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.287.2.1 2007/05/22 23:24:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -614,6 +614,7 @@ _equalOuterJoinInfo(OuterJoinInfo *a, OuterJoinInfo *b)
 	COMPARE_BITMAPSET_FIELD(min_righthand);
 	COMPARE_SCALAR_FIELD(is_full_join);
 	COMPARE_SCALAR_FIELD(lhs_strict);
+	COMPARE_SCALAR_FIELD(delay_upper_joins);
 
 	return true;
 }
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index fdcc2cdc5f6..f80a333b7e2 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.285.2.1 2007/05/22 01:40:42 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.285.2.2 2007/05/22 23:24:08 tgl Exp $
  *
  * NOTES
  *	  Every node type that can appear in stored rules' parsetrees *must*
@@ -1293,6 +1293,7 @@ _outOuterJoinInfo(StringInfo str, OuterJoinInfo *node)
 	WRITE_BITMAPSET_FIELD(min_righthand);
 	WRITE_BOOL_FIELD(is_full_join);
 	WRITE_BOOL_FIELD(lhs_strict);
+	WRITE_BOOL_FIELD(delay_upper_joins);
 }
 
 static void
diff --git a/src/backend/optimizer/plan/initsplan.c b/src/backend/optimizer/plan/initsplan.c
index ef131fba0ee..0b315f2cd7d 100644
--- a/src/backend/optimizer/plan/initsplan.c
+++ b/src/backend/optimizer/plan/initsplan.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.123.2.4 2007/02/16 20:57:26 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.123.2.5 2007/05/22 23:24:08 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -495,6 +495,9 @@ make_outerjoininfo(PlannerInfo *root,
 					 errmsg("SELECT FOR UPDATE/SHARE cannot be applied to the nullable side of an outer join")));
 	}
 
+	/* this always starts out false */
+	ojinfo->delay_upper_joins = false;
+
 	/* If it's a full join, no need to be very smart */
 	ojinfo->is_full_join = is_full_join;
 	if (is_full_join)
@@ -564,10 +567,21 @@ make_outerjoininfo(PlannerInfo *root,
 		 * lower join's RHS and the lower OJ's join condition is strict, we
 		 * can interchange the ordering of the two OJs, so exclude the lower
 		 * RHS from our min_righthand.
+		 *
+		 * Here, we have to consider that "our join condition" includes
+		 * any clauses that syntactically appeared above the lower OJ and
+		 * below ours; those are equivalent to degenerate clauses in our
+		 * OJ and must be treated as such.  Such clauses obviously can't
+		 * reference our LHS, and they must be non-strict for the lower OJ's
+		 * RHS (else reduce_outer_joins would have reduced the lower OJ to
+		 * a plain join).  Hence the other ways in which we handle clauses
+		 * within our join condition are not affected by them.  The net
+		 * effect is therefore sufficiently represented by the
+		 * delay_upper_joins flag saved for us by distribute_qual_to_rels.
 		 */
 		if (bms_overlap(ojinfo->min_righthand, otherinfo->min_righthand) &&
 			!bms_overlap(clause_relids, otherinfo->min_righthand) &&
-			otherinfo->lhs_strict)
+			otherinfo->lhs_strict && !otherinfo->delay_upper_joins)
 		{
 			ojinfo->min_righthand = bms_del_members(ojinfo->min_righthand,
 													otherinfo->min_righthand);
@@ -829,6 +843,10 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
 						/* we'll need another iteration */
 						found_some = true;
 					}
+					/* set delay_upper_joins if needed */
+					if (!ojinfo->is_full_join &&
+						bms_overlap(relids, ojinfo->min_lefthand))
+						ojinfo->delay_upper_joins = true;
 				}
 			}
 		} while (found_some);
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index ad31d536e0b..b1cedcc850a 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.128.2.2 2007/05/22 01:40:42 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.128.2.3 2007/05/22 23:24:09 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -852,6 +852,12 @@ typedef struct InnerIndexscanInfo
  * It is not valid for either min_lefthand or min_righthand to be empty sets;
  * if they were, this would break the logic that enforces join order.
  *
+ * delay_upper_joins is set TRUE if we detect a pushed-down clause that has
+ * to be evaluated after this join is formed (because it references the RHS).
+ * Any outer joins that have such a clause and this join in their RHS cannot
+ * commute with this join, because that would leave noplace to check the
+ * pushed-down clause.  (We don't track this for FULL JOINs, either.)
+ *
  * Note: OuterJoinInfo directly represents only LEFT JOIN and FULL JOIN;
  * RIGHT JOIN is handled by switching the inputs to make it a LEFT JOIN.
  * We make an OuterJoinInfo for FULL JOINs even though there is no flexibility
@@ -865,6 +871,7 @@ typedef struct OuterJoinInfo
 	Relids		min_righthand;	/* base relids in minimum RHS for join */
 	bool		is_full_join;	/* it's a FULL OUTER JOIN */
 	bool		lhs_strict;		/* joinclause is strict for some LHS rel */
+	bool		delay_upper_joins;	/* can't commute with upper RHS */
 } OuterJoinInfo;
 
 /*
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 245e22dcd05..8b6716def81 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -2223,3 +2223,30 @@ select tt1.*, tt2.* from tt2 right join tt1 on tt1.joincol = tt2.joincol;
       2 |         |        |        
 (3 rows)
 
+reset enable_hashjoin;
+reset enable_nestloop;
+--
+-- regression test for 8.2 bug with improper re-ordering of left joins
+--
+create temp table tt3(f1 int, f2 text);
+insert into tt3 select x, repeat('xyzzy', 100) from generate_series(1,10000) x;
+create index tt3i on tt3(f1);
+analyze tt3;
+create temp table tt4(f1 int);
+insert into tt4 values (0),(1),(9999);
+analyze tt4;
+SELECT a.f1
+FROM tt4 a
+LEFT JOIN (
+        SELECT b.f1
+        FROM tt3 b LEFT JOIN tt3 c ON (b.f1 = c.f1)
+        WHERE c.f1 IS NULL
+) AS d ON (a.f1 = d.f1)
+WHERE d.f1 IS NULL;
+  f1  
+------
+    0
+    1
+ 9999
+(3 rows)
+
diff --git a/src/test/regress/expected/join_1.out b/src/test/regress/expected/join_1.out
index 9677408707f..8e7e4de0141 100644
--- a/src/test/regress/expected/join_1.out
+++ b/src/test/regress/expected/join_1.out
@@ -2223,3 +2223,30 @@ select tt1.*, tt2.* from tt2 right join tt1 on tt1.joincol = tt2.joincol;
       2 |         |        |        
 (3 rows)
 
+reset enable_hashjoin;
+reset enable_nestloop;
+--
+-- regression test for 8.2 bug with improper re-ordering of left joins
+--
+create temp table tt3(f1 int, f2 text);
+insert into tt3 select x, repeat('xyzzy', 100) from generate_series(1,10000) x;
+create index tt3i on tt3(f1);
+analyze tt3;
+create temp table tt4(f1 int);
+insert into tt4 values (0),(1),(9999);
+analyze tt4;
+SELECT a.f1
+FROM tt4 a
+LEFT JOIN (
+        SELECT b.f1
+        FROM tt3 b LEFT JOIN tt3 c ON (b.f1 = c.f1)
+        WHERE c.f1 IS NULL
+) AS d ON (a.f1 = d.f1)
+WHERE d.f1 IS NULL;
+  f1  
+------
+    0
+    1
+ 9999
+(3 rows)
+
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index 71208d2d2d8..d3433effd11 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -399,3 +399,28 @@ set enable_nestloop to off;
 select tt1.*, tt2.* from tt1 left join tt2 on tt1.joincol = tt2.joincol;
 
 select tt1.*, tt2.* from tt2 right join tt1 on tt1.joincol = tt2.joincol;
+
+reset enable_hashjoin;
+reset enable_nestloop;
+
+--
+-- regression test for 8.2 bug with improper re-ordering of left joins
+--
+
+create temp table tt3(f1 int, f2 text);
+insert into tt3 select x, repeat('xyzzy', 100) from generate_series(1,10000) x;
+create index tt3i on tt3(f1);
+analyze tt3;
+
+create temp table tt4(f1 int);
+insert into tt4 values (0),(1),(9999);
+analyze tt4;
+
+SELECT a.f1
+FROM tt4 a
+LEFT JOIN (
+        SELECT b.f1
+        FROM tt3 b LEFT JOIN tt3 c ON (b.f1 = c.f1)
+        WHERE c.f1 IS NULL
+) AS d ON (a.f1 = d.f1)
+WHERE d.f1 IS NULL;