From 30d3a692607215b5dd98e15eddfe7128cbcfc245 Mon Sep 17 00:00:00 2001
From: Richard Guo <guofenglinux@gmail.com>
Date: Tue, 20 Sep 2022 15:41:07 +0800
Subject: [PATCH v1] Display NestLoopParam across subplan

---
 src/backend/utils/adt/ruleutils.c       | 34 ++-----------------------
 src/test/regress/expected/join.out      |  8 +++---
 src/test/regress/expected/subselect.out |  2 +-
 3 files changed, 7 insertions(+), 37 deletions(-)

diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 2b7b1b0c0f..ee950fc6f6 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -7900,12 +7900,10 @@ find_param_referent(Param *param, deparse_context *context,
 	{
 		deparse_namespace *dpns;
 		Plan	   *child_plan;
-		bool		in_same_plan_level;
 		ListCell   *lc;
 
 		dpns = (deparse_namespace *) linitial(context->namespaces);
 		child_plan = dpns->plan;
-		in_same_plan_level = true;
 
 		foreach(lc, dpns->ancestors)
 		{
@@ -7913,13 +7911,10 @@ find_param_referent(Param *param, deparse_context *context,
 			ListCell   *lc2;
 
 			/*
-			 * NestLoops transmit params to their inner child only; also, once
-			 * we've crawled up out of a subplan, this couldn't possibly be
-			 * the right match.
+			 * NestLoops transmit params to their inner child only.
 			 */
 			if (IsA(ancestor, NestLoop) &&
-				child_plan == innerPlan(ancestor) &&
-				in_same_plan_level)
+				child_plan == innerPlan(ancestor))
 			{
 				NestLoop   *nl = (NestLoop *) ancestor;
 
@@ -7977,35 +7972,10 @@ find_param_referent(Param *param, deparse_context *context,
 					}
 				}
 
-				/* We have emerged from a subplan. */
-				in_same_plan_level = false;
-
 				/* SubPlan isn't a kind of Plan, so skip the rest */
 				continue;
 			}
 
-			/*
-			 * Check to see if we're emerging from an initplan of the current
-			 * ancestor plan.  Initplans never have any parParams, so no need
-			 * to search that list, but we need to know if we should reset
-			 * in_same_plan_level.
-			 */
-			foreach(lc2, ((Plan *) ancestor)->initPlan)
-			{
-				SubPlan    *subplan = lfirst_node(SubPlan, lc2);
-
-				if (child_plan != (Plan *) list_nth(dpns->subplans,
-													subplan->plan_id - 1))
-					continue;
-
-				/* No parameters to be had here. */
-				Assert(subplan->parParam == NIL);
-
-				/* We have emerged from an initplan. */
-				in_same_plan_level = false;
-				break;
-			}
-
 			/* No luck, crawl up to next ancestor */
 			child_plan = (Plan *) ancestor;
 		}
diff --git a/src/test/regress/expected/join.out b/src/test/regress/expected/join.out
index 2ed2e542a4..48cb0b9f35 100644
--- a/src/test/regress/expected/join.out
+++ b/src/test/regress/expected/join.out
@@ -5985,8 +5985,8 @@ lateral (select * from int8_tbl t1,
                                      where q2 = (select greatest(t1.q1,t2.q2))
                                        and (select v.id=0)) offset 0) ss2) ss
          where t1.q1 = ss.q2) ss0;
-                           QUERY PLAN                            
------------------------------------------------------------------
+                              QUERY PLAN                              
+----------------------------------------------------------------------
  Nested Loop
    Output: "*VALUES*".column1, t1.q1, t1.q2, ss2.q1, ss2.q2
    ->  Seq Scan on public.int8_tbl t1
@@ -6007,10 +6007,10 @@ lateral (select * from int8_tbl t1,
                              One-Time Filter: $4
                              InitPlan 1 (returns $2)
                                ->  Result
-                                     Output: GREATEST($0, t2.q2)
+                                     Output: GREATEST(t1.q1, t2.q2)
                              InitPlan 2 (returns $4)
                                ->  Result
-                                     Output: ($3 = 0)
+                                     Output: ("*VALUES*".column1 = 0)
                              ->  Seq Scan on public.int8_tbl t3
                                    Output: t3.q1, t3.q2
                                    Filter: (t3.q2 = $2)
diff --git a/src/test/regress/expected/subselect.out b/src/test/regress/expected/subselect.out
index 63d26d44fc..22af8fafa1 100644
--- a/src/test/regress/expected/subselect.out
+++ b/src/test/regress/expected/subselect.out
@@ -1155,7 +1155,7 @@ where o.ten = 0;
                SubPlan 1
                  ->  Seq Scan on public.int4_tbl
                        Output: int4_tbl.f1
-                       Filter: (int4_tbl.f1 <= $0)
+                       Filter: (int4_tbl.f1 <= o.hundred)
 (14 rows)
 
 select sum(ss.tst::int) from
-- 
2.31.0