@Override
  protected void rollbackState(final MasterProcedureEnv env, final ModifyTableState state)
    throws IOException {
    if (
      state == ModifyTableState.MODIFY_TABLE_PREPARE
        || state == ModifyTableState.MODIFY_TABLE_PRE_OPERATION
    ) {
      // nothing to rollback, pre-modify is just checks.
      // TODO: coprocessor rollback semantic is still undefined.
      return;
    }

    // The delete doesn't have a rollback. The execution will succeed, at some point.
    throw new UnsupportedOperationException("unhandled state=" + state);
  }
Comparing the value associated with a given key across two TableDescriptor instances'
properties.
@return True if the table property <code>key</code> is the same in both.
hbase-server/src/main/java/org/apache/hadoop/hbase/master/procedure/ModifyTableProcedure.java