protected List<Integer> getBucketColIDs(List<String> bucketCols, List<FieldSchema> cols) {
    ArrayList<Integer> result = new ArrayList<>(bucketCols.size());
    HashSet<String> bucketSet = new HashSet<>(bucketCols);
    for (int i = 0; i < cols.size(); i++) {
      if (bucketSet.contains(cols.get(i).getName())) {
        result.add(i);
      }
    }
    return result;
  }
used to tag error msgs to provided some breadcrumbs
streaming/src/java/org/apache/hive/streaming/AbstractRecordWriter.java