ddl: let concurrent truncate on the same table depend on the previous…

… one (#40501)

* done

Signed-off-by: wjhuang2016 <huangwenjun1997@gmail.com>

* refine test

Signed-off-by: wjhuang2016 <huangwenjun1997@gmail.com>

Signed-off-by: wjhuang2016 <huangwenjun1997@gmail.com>
Co-authored-by: Ti Chi Robot <ti-community-prow-bot@tidb.io>

ddl/db_test.go

@@ -1577,3 +1577,52 @@ func TestSetInvalidDefaultValueAfterModifyColumn(t *testing.T) {
 	wg.Wait()
 	require.EqualError(t, checkErr, "[ddl:1101]BLOB/TEXT/JSON column 'a' can't have a default value")
 }
+
+func TestMDLTruncateTable(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+
+	tk := testkit.NewTestKit(t, store)
+	tk2 := testkit.NewTestKit(t, store)
+	tk3 := testkit.NewTestKit(t, store)
+	tk.MustExec("use test")
+	tk.MustExec("create table t(a int);")
+	tk.MustExec("begin")
+	tk.MustExec("select * from t for update")
+
+	var wg sync.WaitGroup
+
+	hook := &ddl.TestDDLCallback{Do: dom}
+	wg.Add(2)
+	var timetk2 time.Time
+	var timetk3 time.Time
+
+	one := false
+	f := func(job *model.Job) {
+		if !one {
+			one = true
+		} else {
+			return
+		}
+		go func() {
+			tk3.MustExec("truncate table test.t")
+			timetk3 = time.Now()
+			wg.Done()
+		}()
+	}
+
+	hook.OnJobUpdatedExported.Store(&f)
+	dom.DDL().SetHook(hook)
+
+	go func() {
+		tk2.MustExec("truncate table test.t")
+		timetk2 = time.Now()
+		wg.Done()
+	}()
+
+	time.Sleep(2 * time.Second)
+	timeMain := time.Now()
+	tk.MustExec("commit")
+	wg.Wait()
+	require.True(t, timetk2.After(timeMain))
+	require.True(t, timetk3.After(timeMain))
+}

ddl/job_table.go

@@ -370,6 +370,8 @@ func job2UniqueIDs(job *model.Job, schema bool) string {
 		}
 		slices.Sort(s)
 		return strings.Join(s, ",")
+	case model.ActionTruncateTable:
+		return strconv.FormatInt(job.TableID, 10) + "," + strconv.FormatInt(job.Args[0].(int64), 10)
 	}
 	if schema {
 		return strconv.FormatInt(job.SchemaID, 10)

ddl/metadatalocktest/mdl_test.go

@@ -12,8 +12,6 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-//go:build !featuretag
-
 package metadatalocktest
 
 import (