From 78166329e2708e8a44e578f597a2f4884a563e8c Mon Sep 17 00:00:00 2001
From: HuaiyuXu <391585975@qq.com>
Date: Sat, 5 Sep 2020 17:24:57 +0800
Subject: [PATCH] executor: set the correct resultCh for task when
 indexHashJoin keep order (#18840)

* executor: set the correct resultCh for task when indexHashJoin keep order (#18757)

* update test

Co-authored-by: ti-srebot <66930949+ti-srebot@users.noreply.github.com>
---
 executor/index_lookup_hash_join.go    | 10 +++---
 executor/seqtest/seq_executor_test.go | 47 +++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/executor/index_lookup_hash_join.go b/executor/index_lookup_hash_join.go
index d0ca46488c..49eb1bb2a9 100644
--- a/executor/index_lookup_hash_join.go
+++ b/executor/index_lookup_hash_join.go
@@ -320,10 +320,11 @@ func (ow *indexHashJoinOuterWorker) run(ctx context.Context) {
 		})
 		if err != nil {
 			task = &indexHashJoinTask{err: err}
-			ow.pushToChan(ctx, task, ow.innerCh)
 			if ow.keepOuterOrder {
+				task.keepOuterOrder, task.resultCh = true, make(chan *indexHashJoinResult, 1)
 				ow.pushToChan(ctx, task, ow.taskCh)
 			}
+			ow.pushToChan(ctx, task, ow.innerCh)
 			return
 		}
 		if task == nil {
@@ -452,13 +453,14 @@ func (iw *indexHashJoinInnerWorker) run(ctx context.Context, cancelFunc context.
 		if !ok {
 			break
 		}
+		// We need to init resultCh before the err is returned.
+		if task.keepOuterOrder {
+			resultCh = task.resultCh
+		}
 		if task.err != nil {
 			joinResult.err = task.err
 			break
 		}
-		if task.keepOuterOrder {
-			resultCh = task.resultCh
-		}
 		err := iw.handleTask(ctx, task, joinResult, h, resultCh)
 		if err != nil {
 			joinResult.err = err
diff --git a/executor/seqtest/seq_executor_test.go b/executor/seqtest/seq_executor_test.go
index 7e61308f7c..2249c2ce53 100644
--- a/executor/seqtest/seq_executor_test.go
+++ b/executor/seqtest/seq_executor_test.go
@@ -1422,6 +1422,53 @@ func (s *seqTestSuite) TestOOMPanicInHashJoinWhenFetchBuildRows(c *C) {
 	c.Assert(err.Error(), Equals, "failpoint panic: ERROR 1105 (HY000): Out Of Memory Quota![conn_id=1]")
 }
 
+func (s *seqTestSuite) TestIssue18744(c *C) {
+	tk := testkit.NewTestKitWithInit(c, s.store)
+	tk.MustExec(`use test;`)
+	tk.MustExec(`drop table if exists t, t1;`)
+	tk.MustExec(`CREATE TABLE t (
+  id int(11) NOT NULL,
+  a bigint(20) DEFAULT NULL,
+  b char(20) DEFAULT NULL,
+  c datetime DEFAULT NULL,
+  d double DEFAULT NULL,
+  e json DEFAULT NULL,
+  f decimal(40,6) DEFAULT NULL,
+  PRIMARY KEY (id),
+  KEY a (a),
+  KEY b (b),
+  KEY c (c),
+  KEY d (d),
+  KEY f (f)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;`)
+	tk.MustExec(`CREATE TABLE t1 (
+  id int(11) NOT NULL,
+  a bigint(20) DEFAULT NULL,
+  b char(20) DEFAULT NULL,
+  c datetime DEFAULT NULL,
+  d double DEFAULT NULL,
+  e json DEFAULT NULL,
+  f decimal(40,6) DEFAULT NULL,
+  PRIMARY KEY (id),
+  KEY a (a),
+  KEY b (b),
+  KEY c (c),
+  KEY d (d),
+  KEY f (f)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;`)
+	tk.MustExec(`insert into t1(id) values(0),(1),(2);`)
+	tk.MustExec(`insert into t values(0, 2010,  "2010-01-01 01:01:00" , "2010-01-01 01:01:00" , 2010 , 2010 , 2010.000000);`)
+	tk.MustExec(`insert into t values(1 , NULL , NULL                , NULL                , NULL , NULL ,        NULL);`)
+	tk.MustExec(`insert into t values(2 , 2012 , "2012-01-01 01:01:00" , "2012-01-01 01:01:00" , 2012 , 2012 , 2012.000000);`)
+	tk.MustExec(`set tidb_index_lookup_join_concurrency=1`)
+	c.Assert(failpoint.Enable("github.com/pingcap/tidb/executor/testIndexHashJoinOuterWorkerErr", "return"), IsNil)
+	defer func() {
+		c.Assert(failpoint.Disable("github.com/pingcap/tidb/executor/testIndexHashJoinOuterWorkerErr"), IsNil)
+	}()
+	err := tk.QueryToErr(`select /*+ inl_hash_join(t2) */ t1.id, t2.id from t1 join t t2 on t1.a = t2.a order by t1.a ASC limit 1;`)
+	c.Assert(err.Error(), Equals, "mockIndexHashJoinOuterWorkerErr")
+}
+
 func (s *seqTestSuite) TestIssue19410(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")