@SuppressWarnings("unchecked")
    @Override
    public Object dispatch(Node nd, Stack<Node> stack, Object... nodeOutputs)
      throws SemanticException {
      Task<?> currTask = (Task<?>) nd;
      if (currTask instanceof StatsTask) {
        currTask = ((StatsTask) currTask).getWork().getSourceTask();
      }
      if (currTask instanceof TezTask) {
        TezWork work = ((TezTask) currTask).getWork();
        for (BaseWork w : work.getAllWork()) {
          evaluateWork(w);
        }
      }
      return null;
    }
SerializeFilter is a simple physical optimizer that serializes all filter expressions in
Tablescan Operators.
ql/src/java/org/apache/hadoop/hive/ql/optimizer/physical/SerializeFilter.java