From 4d0c1c3c2f406655d0c10dcc8ad45bbb848b34e8 Mon Sep 17 00:00:00 2001
From: laishenghao <laishenghao1@huawei.com>
Date: Wed, 26 Mar 2025 17:11:19 +0800
Subject: [PATCH] =?UTF-8?q?=E8=A7=A3=E5=86=B3union=20all=E5=87=BA=E7=8E=B0?=
 =?UTF-8?q?core=E9=97=AE=E9=A2=98?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 src/gausskernel/optimizer/plan/createplan.cpp |  5 ++
 .../expected/test_union_all_orderby.out       | 51 +++++++++++++++++++
 .../regress/sql/test_union_all_orderby.sql    | 24 ++++++++-
 3 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/src/gausskernel/optimizer/plan/createplan.cpp b/src/gausskernel/optimizer/plan/createplan.cpp
index c326b70cd9..d4b079f077 100755
--- a/src/gausskernel/optimizer/plan/createplan.cpp
+++ b/src/gausskernel/optimizer/plan/createplan.cpp
@@ -2699,6 +2699,11 @@ static Scan* create_indexscan_plan(
         qpqual = lappend(qpqual, rinfo);
     }
 
+    if (u_sess->opt_cxt.is_under_append_plan && tlist == NIL) {
+        Const *c = makeConst(INT4OID, -1, InvalidOid, -2, (Datum)0, true, false);
+        tlist = lappend(tlist, makeTargetEntry((Expr*)c, 1, NULL, true));
+    }
+
     /* Sort clauses into best execution order */
     qpqual = order_qual_clauses(root, qpqual);
 
diff --git a/src/test/regress/expected/test_union_all_orderby.out b/src/test/regress/expected/test_union_all_orderby.out
index a0da822e95..05eb1fd43a 100644
--- a/src/test/regress/expected/test_union_all_orderby.out
+++ b/src/test/regress/expected/test_union_all_orderby.out
@@ -41,3 +41,54 @@ insert into tb3 values(6);
  7
 (7 rows)
 
+reset enable_union_all_subquery_orderby;
+-- test union all with none targetlist
+drop table if exists union_pseudo_tlist cascade;
+NOTICE:  table "union_pseudo_tlist" does not exist, skipping
+create table union_pseudo_tlist(id int);
+insert into union_pseudo_tlist values(1);
+create index on union_pseudo_tlist(id);
+set enable_seqscan=off;
+select count(*) from union_pseudo_tlist where now() is not null and id is not null;
+ count 
+-------
+     1
+(1 row)
+
+explain(costs off) select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where now() is not null;
+                                          QUERY PLAN                                           
+-----------------------------------------------------------------------------------------------
+ Aggregate
+   ->  Result
+         One-Time Filter: (now() IS NOT NULL)
+         ->  Append
+               ->  Result
+                     One-Time Filter: (now() IS NOT NULL)
+                     ->  Index Only Scan using union_pseudo_tlist_id_idx on union_pseudo_tlist
+               ->  Result
+                     One-Time Filter: (now() IS NOT NULL)
+                     ->  Index Only Scan using union_pseudo_tlist_id_idx on union_pseudo_tlist
+(10 rows)
+
+select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where now() is not null;
+ count 
+-------
+     2
+(1 row)
+
+select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where now() is not null and id is not null;
+ count 
+-------
+     2
+(1 row)
+
+-- use pbe
+prepare test_index_pseudo as select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where id in (1) and id=$1;
+execute test_index_pseudo(1);
+ count 
+-------
+     2
+(1 row)
+
+drop table if exists union_pseudo_tlist cascade;
+reset enable_seqscan;
diff --git a/src/test/regress/sql/test_union_all_orderby.sql b/src/test/regress/sql/test_union_all_orderby.sql
index d239a68d29..4902347762 100644
--- a/src/test/regress/sql/test_union_all_orderby.sql
+++ b/src/test/regress/sql/test_union_all_orderby.sql
@@ -12,4 +12,26 @@ insert into tb3 values(6);
 
 (select * from tb1 order by a) union all (select * from tb2 order by a);
 (select * from tb1 order by a) union all (select * from tb2 order by a desc);
-(select * from tb1 order by a) union all (select * from tb2 order by a) union all (select * from tb3 order by a);
\ No newline at end of file
+(select * from tb1 order by a) union all (select * from tb2 order by a) union all (select * from tb3 order by a);
+
+reset enable_union_all_subquery_orderby;
+
+-- test union all with none targetlist
+drop table if exists union_pseudo_tlist cascade;
+create table union_pseudo_tlist(id int);
+insert into union_pseudo_tlist values(1);
+create index on union_pseudo_tlist(id);
+set enable_seqscan=off;
+
+select count(*) from union_pseudo_tlist where now() is not null and id is not null;
+
+explain(costs off) select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where now() is not null;
+select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where now() is not null;
+select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where now() is not null and id is not null;
+
+-- use pbe
+prepare test_index_pseudo as select count(*) from (select * from union_pseudo_tlist union all select * from union_pseudo_tlist) where id in (1) and id=$1;
+execute test_index_pseudo(1);
+
+drop table if exists union_pseudo_tlist cascade;
+reset enable_seqscan;
-- 
Gitee