address comment

pkg/task/restore.go

@@ -48,21 +48,18 @@ const (
 type RestoreConfig struct {
 	Config
 
-	Online         bool `json:"online" toml:"online"`
-	NoSchema       bool `json:"no-schema" toml:"no-schema"`
-	MaxIndexLength int  `json:"max-index-length" toml:"max-index-length"`
+	Online   bool `json:"online" toml:"online"`
+	NoSchema bool `json:"no-schema" toml:"no-schema"`
 }
 
 // DefineRestoreFlags defines common flags for the restore command.
 func DefineRestoreFlags(flags *pflag.FlagSet) {
 	// TODO remove experimental tag if it's stable
 	flags.Bool(flagOnline, false, "(experimental) Whether online when restore")
 	flags.Bool(flagNoSchema, false, "skip creating schemas and tables, reuse existing empty ones")
-	flags.Int(flagMaxIndexLength, 3072, "need keep this as same as tidb max-index-length")
 
 	// Do not expose this flag
 	_ = flags.MarkHidden(flagNoSchema)
-	_ = flags.MarkHidden(flagMaxIndexLength)
 }
 
 // ParseFromFlags parses the restore-related flags from the flag set.
@@ -76,10 +73,6 @@ func (cfg *RestoreConfig) ParseFromFlags(flags *pflag.FlagSet) error {
 	if err != nil {
 		return errors.Trace(err)
 	}
-	cfg.MaxIndexLength, err = flags.GetInt(flagMaxIndexLength)
-	if err != nil {
-		return errors.Trace(err)
-	}
 	err = cfg.Config.ParseFromFlags(flags)
 	if err != nil {
 		return errors.Trace(err)
@@ -158,9 +151,11 @@ func RunRestore(c context.Context, g glue.Glue, cmdName string, cfg *RestoreConf
 	}
 	// execute DDL first
 
-	// set max index length before execute DDLs and create tables
+	// set max-index-length before execute DDLs and create tables
+	// we set this value to max(3072*4), otherwise we might not restore table
+	// when upstream and downstream both set this value greater than default(3072)
 	conf := config.GetGlobalConfig()
-	conf.MaxIndexLength = cfg.MaxIndexLength
+	conf.MaxIndexLength = config.DefMaxOfMaxIndexLength
 	config.StoreGlobalConfig(conf)
 
 	err = client.ExecDDLs(ddlJobs)