@Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append("{fileId=").append(fileId).append(", schemaHash=").append(schemaHash).append('}');
    return sb.toString();
  }
Cache key that stores schema hash. Useful caching serdes that do not have a self-describing schema built in.
ql/src/java/org/apache/hadoop/hive/llap/SchemaAwareCacheKey.java