executor: fix data race in the index_lookup_hash_join (#30619)

executor/index_lookup_hash_join.go

@@ -168,19 +168,17 @@ func (e *IndexNestedLoopHashJoin) startWorkers(ctx context.Context) {
 	innerCh := make(chan *indexHashJoinTask, concurrency)
 	if e.keepOuterOrder {
 		e.taskCh = make(chan *indexHashJoinTask, concurrency)
-	}
-	e.workerWg.Add(1)
-	ow := e.newOuterWorker(innerCh)
-	go util.WithRecovery(func() { ow.run(workerCtx) }, e.finishJoinWorkers)
-
-	if !e.keepOuterOrder {
-		e.resultCh = make(chan *indexHashJoinResult, concurrency)
-	} else {
 		// When `keepOuterOrder` is true, each task holds their own `resultCh`
 		// individually, thus we do not need a global resultCh.
 		e.resultCh = nil
+	} else {
+		e.resultCh = make(chan *indexHashJoinResult, concurrency)
 	}
 	e.joinChkResourceCh = make([]chan *chunk.Chunk, concurrency)
+	e.workerWg.Add(1)
+	ow := e.newOuterWorker(innerCh)
+	go util.WithRecovery(func() { ow.run(workerCtx) }, e.finishJoinWorkers)
+
 	for i := 0; i < concurrency; i++ {
 		if !e.keepOuterOrder {
 			e.joinChkResourceCh[i] = make(chan *chunk.Chunk, 1)