public static long getTotalInputFileSize (ContentSummary inputSummary, MapWork work,
      double highestSamplePercentage) {
    long totalInputFileSize = inputSummary.getLength();
    if (MapUtils.isEmpty(work.getNameToSplitSample())) {
      // If percentage block sampling wasn't used, we don't need to do any estimation
      return totalInputFileSize;
    }

    if (highestSamplePercentage >= 0) {
      totalInputFileSize = Math.min((long) (totalInputFileSize * (highestSamplePercentage / 100D))
          , totalInputFileSize);
    }
    return totalInputFileSize;
  }
Computes the total input file size. If block sampling was used it will scale this
value by the highest sample percentage (as an estimate for input).

@param inputSummary
@param work
@param highestSamplePercentage
@return estimated total input size for job
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java