@Override
  public AggregationBuffer getNewAggregationBuffer() throws HiveException {
    if (expectedEntries < 0) {
      throw new IllegalStateException("expectedEntries not initialized");
    }
    return new Aggregation(expectedEntries, numThreads);
  }
Executor.shutdownNow() is supposed to send Thread.interrupt to worker threads, and they are
supposed to finish their work.
ql/src/java/org/apache/hadoop/hive/ql/exec/vector/expressions/aggregates/VectorUDAFBloomFilterMerge.java