diff --git a/simpledb/tx/concurrency_lock_test.go b/simpledb/tx/concurrency_lock_test.go
index 62d3945..9ab168c 100644
--- a/simpledb/tx/concurrency_lock_test.go
+++ b/simpledb/tx/concurrency_lock_test.go
@@ -164,3 +164,55 @@ func TestConcurrencyXLockTimeout(t *testing.T) {
 
 	wg.Wait()
 }
+
+func TestConcurrencyXLockMany(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping test in short mode, this takes long time for checking timeout.")
+	}
+
+	db, err := server.NewSimpleDB(path.Join(t.TempDir(), "concurrencytest"), 400, 8)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	fm := db.FileManager()
+	lm := db.LogManager()
+	bm := db.BufferManager()
+
+	n := 10
+
+	wg := &sync.WaitGroup{}
+	wg.Add(n)
+
+	for i := range n {
+		go func(i int) {
+			defer wg.Done()
+
+			txA, err := tx.New(fm, lm, bm)
+			if err != nil {
+				panic(err)
+			}
+			blk1 := file.NewBlockID("testfile", 1)
+			err = txA.Pin(blk1)
+			if err != nil {
+				panic(err)
+			}
+			t.Logf("Tx %d: request xlock 1", i)
+			err = txA.SetInt(blk1, 0, 0, false)
+			if err != nil {
+				panic(err)
+			}
+			t.Logf("Tx %d: receive xlock 1", i)
+			time.Sleep(50 * time.Millisecond)
+
+			t.Logf("Tx %d: commit", i)
+			if err := txA.Commit(); err != nil {
+				panic(err)
+			}
+		}(i)
+
+		time.Sleep(10 * time.Millisecond)
+	}
+
+	wg.Wait()
+}