public void loadFileFooter() {
    MemoryBufferOrBuffers tailBuffers = metadataCache.getFileMetadata(fileKey);
    if (tailBuffers == null) {
      ByteBuffer tailBufferBb = orcReader.getSerializedFileFooter();
      metadataCache.putFileMetadata(fileKey, tailBufferBb, cacheTag, null);
    }
  }
Pre read the file footer into the cache.
llap-server/src/java/org/apache/hadoop/hive/llap/io/encoded/LlapOrcCacheLoader.java