ddl: simplify TestMDLPreparePlanCacheExecuteInsert (#58113)

.bazelversion

@@ -0,0 +1 @@
+7.4.1

pkg/ddl/tests/metadatalock/mdl_test.go

@@ -997,6 +997,86 @@ func TestMDLPreparePlanCacheExecute2(t *testing.T) {
 	tk.MustExec("admin check table t")
 }
 
+<<<<<<< HEAD
+=======
+// TestMDLPreparePlanCacheExecuteInsert makes sure the insert statement handle the schema correctly in plan cache.
+func TestMDLPreparePlanCacheExecuteInsert(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+	defer ingesttestutil.InjectMockBackendMgr(t, store)()
+
+	sv := server.CreateMockServer(t, store)
+
+	sv.SetDomain(dom)
+	dom.InfoSyncer().SetSessionManager(sv)
+	defer sv.Close()
+
+	conn1 := server.CreateMockConn(t, sv)
+	tk := testkit.NewTestKitWithSession(t, store, conn1.Context().Session)
+	conn2 := server.CreateMockConn(t, sv)
+	tkDDL := testkit.NewTestKitWithSession(t, store, conn2.Context().Session)
+	tk.MustExec("use test")
+	tk.MustExec("set global tidb_enable_metadata_lock=1")
+	tk.MustExec("create table t(a int primary key, b int);")
+	tk.MustExec("create table t2(a int);")
+	tk.MustExec("insert into t values(1, 1), (2, 2), (3, 3), (4, 4);")
+
+	tk.MustExec(`prepare insert_stmt from 'insert into t values (?, ?)'`)
+	tk.MustExec(`set @a=4, @b=4;`)
+
+	ch := make(chan struct{})
+
+	first := true
+	testfailpoint.EnableCall(t, "github.com/pingcap/tidb/pkg/ddl/onJobUpdated", func(job *model.Job) {
+		switch job.SchemaState {
+		case model.StateWriteReorganization:
+			tbl, _ := dom.InfoSchema().TableByID(context.Background(), job.TableID)
+			idx := tbl.Meta().FindIndexByName("idx")
+			switch idx.BackfillState {
+			case model.BackfillStateRunning:
+				if first {
+					// generate plan, cache it, and make some row change to make
+					// sure backfill state 'merging' is not skipped.
+					tk.MustExec(`begin`)
+					tk.MustExec(`delete from t where a = 4;`)
+					tk.MustExec(`execute insert_stmt using @a, @b;`)
+					tk.MustQuery("select @@last_plan_from_cache;").Check(testkit.Rows("0"))
+					tk.MustExec(`commit`)
+
+					tk.MustExec("begin")
+					// Activate txn.
+					tk.MustExec("select * from t2")
+					first = false
+					return
+				}
+			}
+		}
+	})
+
+	ddl.MockDMLExecutionMerging = func() {
+		tk.MustExec(`delete from t where a = 4;`)
+		// we must generate a new plan here, because the schema has changed since
+		// the last plan was generated.
+		tk.MustExec(`execute insert_stmt using @a, @b;`)
+		tk.MustQuery("select @@last_plan_from_cache;").Check(testkit.Rows("0"))
+		tk.MustExec("commit")
+	}
+	require.NoError(t, failpoint.Enable("github.com/pingcap/tidb/pkg/ddl/mockDMLExecutionMerging", "1*return(true)->return(false)"))
+
+	var wg sync.WaitGroup
+	wg.Add(1)
+	go func() {
+		<-ch
+		tkDDL.MustExec("alter table test.t add index idx(a);")
+		wg.Done()
+	}()
+
+	ch <- struct{}{}
+	wg.Wait()
+
+	tk.MustExec("admin check table t")
+}
+
+>>>>>>> 93295c233a3 (ddl: simplify TestMDLPreparePlanCacheExecuteInsert (#58113))
 func TestMDLDisable2Enable(t *testing.T) {
 	store, dom := testkit.CreateMockStoreAndDomain(t)
 	sv := server.CreateMockServer(t, store)

pkg/table/tables/index.go

@@ -264,6 +264,8 @@ func (c *index) create(sctx table.MutateContext, txn kv.Transaction, indexedValu
 				tempVal := tablecodec.TempIndexValueElem{Value: idxVal, KeyVer: keyVer, Distinct: distinct}
 				val = tempVal.Encode(nil)
 			}
+			// during some step of add-index, such as in write-reorg state, this
+			// key is THE temp index key.
 			err = txn.GetMemBuffer().Set(key, val)
 			if err != nil {
 				return nil, err