Path getSerializedFilePath(int index) {
      // e.g. staging_dir/events/queryid/inputtable_InputDataInformationEvent_0
      return new Path(String.format(FILE_PATH_FORMAT, appStagingPath, queryId, vertexId, inputName, index));
    }
SplitSerializer is a helper class for taking care of serializing splits to the tez scratch dir
when a size criteria defined by "hive.tez.input.fs.serialization.threshold" is met.
It utilizes an ExecutorService for parallel writes to prevent a single split write operation
becoming the bottleneck (as write() is called from a loop currently).
ql/src/java/org/apache/hadoop/hive/ql/exec/tez/HiveSplitGenerator.java