@Override
  protected void rollbackState(MasterProcedureEnv env, MigrateNamespaceTableProcedureState state)
    throws IOException, InterruptedException {
  }
Migrate the namespace data to meta table's namespace family while upgrading
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/MigrateNamespaceTableProcedure.java