public int getNumberOfWaitingMergeTasks(){
      int size = 0;
      for (BloomFilterMergeWorker w : workers){
        size += w.queue.size();
      }
      return size;
    }
class for storing the current aggregate value.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/aggregates/VectorUDAFBloomFilterMerge.java