ddl: never write untouched index values to temp index (#41879) (#41884)

close #41880

ddl/index_merge_tmp_test.go

@@ -870,3 +870,44 @@ func TestAddIndexMultipleDelete(t *testing.T) {
  tk.MustQuery("select * from t;").Check(testkit.Rows())
  require.NoError(t, failpoint.Disable("github.com/pingcap/tidb/ddl/mockDMLExecution"))
 }
+
+func TestAddIndexUpdateUntouchedValues(t *testing.T) {
+ store, dom := testkit.CreateMockStoreAndDomain(t)
+
+ tk := testkit.NewTestKit(t, store)
+ tk.MustExec("use test")
+ tk.MustExec("create table t(id int primary key, b int, k int);")
+ tk.MustExec("insert into t values (1, 1, 1);")
+
+ tk1 := testkit.NewTestKit(t, store)
+ tk1.MustExec("use test")
+
+ d := dom.DDL()
+ originalCallback := d.GetHook()
+ defer d.SetHook(originalCallback)
+ callback := &ddl.TestDDLCallback{}
+ var runDML bool
+ callback.OnJobRunBeforeExported = func(job *model.Job) {
+ if t.Failed() || runDML {
+ return
+ }
+ switch job.SchemaState {
+ case model.StateWriteReorganization:
+ _, err := tk1.Exec("begin;")
+ assert.NoError(t, err)
+ _, err = tk1.Exec("update t set k=k+1 where id = 1;")
+ assert.NoError(t, err)
+ _, err = tk1.Exec("insert into t values (2, 1, 2);")
+ // Should not report "invalid temp index value".
+ assert.NoError(t, err)
+ _, err = tk1.Exec("commit;")
+ assert.NoError(t, err)
+ runDML = true
+ }
+ }
+ d.SetHook(callback)
+
+ tk.MustGetErrCode("alter table t add unique index idx(b);", errno.ErrDupEntry)
+ tk.MustExec("admin check table t;")
+ tk.MustQuery("select * from t;").Check(testkit.Rows("1 1 2", "2 1 2"))
+}

ddl/ingest/engine.go

@@ -204,7 +204,7 @@ func (ei *engineInfo) newWriterContext(workerID int, unique bool) (*WriterContex
 
 func (ei *engineInfo) closeWriters() error {
  var firstErr error
- for wid := range ei.writerCache.Keys() {
+ for _, wid := range ei.writerCache.Keys() {
  if w, ok := ei.writerCache.Load(wid); ok {
  _, err := w.Close(ei.ctx)
  if err != nil {

table/tables/index.go

@@ -177,7 +177,12 @@ func (c *index) Create(sctx sessionctx.Context, txn kv.Transaction, indexedValue
 
  if !distinct || skipCheck || opt.Untouched {
  val := idxVal
- if keyIsTempIdxKey && !opt.Untouched { // Untouched key-values never occur in the storage.
+ if opt.Untouched && (keyIsTempIdxKey || len(tempKey) > 0) {
+ // Untouched key-values never occur in the storage and the temp index is not public.
+ // It is unnecessary to write the untouched temp index key-values.
+ return nil, nil
+ }
+ if keyIsTempIdxKey {
  tempVal := tablecodec.TempIndexValueElem{Value: idxVal, KeyVer: keyVer, Distinct: distinct}
  val = tempVal.Encode(nil)
  }
@@ -186,10 +191,8 @@ func (c *index) Create(sctx sessionctx.Context, txn kv.Transaction, indexedValue
  return nil, err
  }
  if len(tempKey) > 0 {
- if !opt.Untouched { // Untouched key-values never occur in the storage.
- tempVal := tablecodec.TempIndexValueElem{Value: idxVal, KeyVer: keyVer, Distinct: distinct}
- val = tempVal.Encode(nil)
- }
+ tempVal := tablecodec.TempIndexValueElem{Value: idxVal, KeyVer: keyVer, Distinct: distinct}
+ val = tempVal.Encode(nil)
  err = txn.GetMemBuffer().Set(tempKey, val)
  if err != nil {
  return nil, err