public static Path createBucketFile(Path subdir, int bucket, Integer attemptId) {
    return createBucketFile(subdir, bucket, attemptId, true);
  }
Create the bucket filename in Acid format
@param subdir the subdirectory for the bucket.
@param bucket the bucket number
@return the filename
ql/src/java/org/apache/hadoop/hive/ql/io/AcidUtils.java