@Override
  public FSDataInputStream open(Path path, int bufferSize) throws IOException {
    return new FSDataInputStream(getCtx(path).cloneWithBufferSize(bufferSize));
  }
This is currently only used by Parquet; however, a generally applicable approach is used -
you pass in a set of offset pairs for a file, and the file is cached with these boundaries.
Don't add anything format specific here.
ql/src/java/org/apache/hadoop/hive/llap/LlapCacheAwareFs.java