0002-minimal-fix-for-pull_varnos.patch

diff --git a/src/backend/optimizer/util/var.c b/src/backend/optimizer/util/var.c
index 19b2bba707..ad275cba3a 100644
--- a/src/backend/optimizer/util/var.c
+++ b/src/backend/optimizer/util/var.c
@@ -159,33 +159,28 @@ pull_varnos_walker(Node *node, pull_varnos_context *context)
 	}
 	if (IsA(node, PlaceHolderVar))
 	{
-		/*
-		 * A PlaceHolderVar acts as a variable of its syntactic scope, or
-		 * lower than that if it references only a subset of the rels in its
-		 * syntactic scope.  It might also contain lateral references, but we
-		 * should ignore such references when computing the set of varnos in
-		 * an expression tree.  Also, if the PHV contains no variables within
-		 * its syntactic scope, it will be forced to be evaluated exactly at
-		 * the syntactic scope, so take that as the relid set.
-		 */
 		PlaceHolderVar *phv = (PlaceHolderVar *) node;
-		pull_varnos_context subcontext;
 
-		subcontext.varnos = NULL;
-		subcontext.sublevels_up = context->sublevels_up;
-		(void) pull_varnos_walker((Node *) phv->phexpr, &subcontext);
+		/*
+		 * If a PlaceHolderVar is not of the target query level, ignore it,
+		 * instead recursing into its expression to see if it contains any
+		 * vars that are of the target level.
+		 */
 		if (phv->phlevelsup == context->sublevels_up)
 		{
-			subcontext.varnos = bms_int_members(subcontext.varnos,
-												phv->phrels);
-			if (bms_is_empty(subcontext.varnos))
-				context->varnos = bms_add_members(context->varnos,
-												  phv->phrels);
+			/*
+			 * Ideally, the PHV's contribution to context->varnos is its
+			 * ph_eval_at set.  However, this code can be invoked before
+			 * that's been computed, and we lack easy access to it anyway.
+			 * Instead make the conservative assumption that the PHV will be
+			 * evaluated at its syntactic level (phv->phrels).
+			 */
+			context->varnos = bms_add_members(context->varnos,
+											  phv->phrels);
+			return false;		/* don't recurse into expression */
 		}
-		context->varnos = bms_join(context->varnos, subcontext.varnos);
-		return false;
 	}
-	if (IsA(node, Query))
+	else if (IsA(node, Query))
 	{
 		/* Recurse into RTE subquery or not-yet-planned sublink subquery */
 		bool		result;
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 81b42c601b..43d684a11a 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -4726,18 +4726,22 @@ from
      left join uniquetbl u1 ON u1.f1 = t1.string4) ss
   on t0.f1 = ss.case1
 where ss.stringu2 !~* ss.case1;
-                                         QUERY PLAN                                         
---------------------------------------------------------------------------------------------
+                                          QUERY PLAN                                          
+----------------------------------------------------------------------------------------------
  Nested Loop
    Join Filter: (CASE t1.ten WHEN 0 THEN 'doh!'::text ELSE NULL::text END = t0.f1)
-   ->  Nested Loop
-         ->  Seq Scan on int4_tbl i4
-         ->  Index Scan using tenk1_unique2 on tenk1 t1
-               Index Cond: (unique2 = i4.f1)
-               Filter: (stringu2 !~* CASE ten WHEN 0 THEN 'doh!'::text ELSE NULL::text END)
+   ->  Hash Right Join
+         Hash Cond: (u1.f1 = t1.string4)
+         Filter: (t1.stringu2 !~* (CASE t1.ten WHEN 0 THEN 'doh!'::text ELSE NULL::text END))
+         ->  Seq Scan on uniquetbl u1
+         ->  Hash
+               ->  Nested Loop
+                     ->  Seq Scan on int4_tbl i4
+                     ->  Index Scan using tenk1_unique2 on tenk1 t1
+                           Index Cond: (unique2 = i4.f1)
    ->  Materialize
          ->  Seq Scan on text_tbl t0
-(9 rows)
+(13 rows)
 
 select t0.*
 from
@@ -4756,6 +4760,42 @@ where ss.stringu2 !~* ss.case1;
 (1 row)
 
 rollback;
+-- test case to expose miscomputation of required relid set for a PHV
+explain (verbose, costs off)
+select i8.*, ss.v, t.unique2
+  from int8_tbl i8
+    left join int4_tbl i4 on i4.f1 = 1
+    left join lateral (select i4.f1 + 1 as v) as ss on true
+    left join tenk1 t on t.unique2 = ss.v
+where q2 = 456;
+                         QUERY PLAN                          
+-------------------------------------------------------------
+ Nested Loop Left Join
+   Output: i8.q1, i8.q2, ((i4.f1 + 1)), t.unique2
+   ->  Nested Loop Left Join
+         Output: i8.q1, i8.q2, (i4.f1 + 1)
+         ->  Seq Scan on public.int8_tbl i8
+               Output: i8.q1, i8.q2
+               Filter: (i8.q2 = 456)
+         ->  Seq Scan on public.int4_tbl i4
+               Output: i4.f1
+               Filter: (i4.f1 = 1)
+   ->  Index Only Scan using tenk1_unique2 on public.tenk1 t
+         Output: t.unique2
+         Index Cond: (t.unique2 = ((i4.f1 + 1)))
+(13 rows)
+
+select i8.*, ss.v, t.unique2
+  from int8_tbl i8
+    left join int4_tbl i4 on i4.f1 = 1
+    left join lateral (select i4.f1 + 1 as v) as ss on true
+    left join tenk1 t on t.unique2 = ss.v
+where q2 = 456;
+ q1  | q2  | v | unique2 
+-----+-----+---+---------
+ 123 | 456 |   |        
+(1 row)
+
 -- bug #8444: we've historically allowed duplicate aliases within aliased JOINs
 select * from
   int8_tbl x join (int4_tbl x cross join int4_tbl y) j on q1 = f1; -- error
diff --git a/src/test/regress/sql/join.sql b/src/test/regress/sql/join.sql
index 9887fe0c0b..6a209a27aa 100644
--- a/src/test/regress/sql/join.sql
+++ b/src/test/regress/sql/join.sql
@@ -1696,6 +1696,22 @@ where ss.stringu2 !~* ss.case1;
 
 rollback;
 
+-- test case to expose miscomputation of required relid set for a PHV
+explain (verbose, costs off)
+select i8.*, ss.v, t.unique2
+  from int8_tbl i8
+    left join int4_tbl i4 on i4.f1 = 1
+    left join lateral (select i4.f1 + 1 as v) as ss on true
+    left join tenk1 t on t.unique2 = ss.v
+where q2 = 456;
+
+select i8.*, ss.v, t.unique2
+  from int8_tbl i8
+    left join int4_tbl i4 on i4.f1 = 1
+    left join lateral (select i4.f1 + 1 as v) as ss on true
+    left join tenk1 t on t.unique2 = ss.v
+where q2 = 456;
+
 -- bug #8444: we've historically allowed duplicate aliases within aliased JOINs
 
 select * from