@Override
    public OrcStruct createValue() {
      return new OrcStruct(numColumns);
    }
We can derive if a split is ACID or not from the flags encoded in OrcSplit.
If the file split is not instance of OrcSplit then its definitely not ACID.
If file split is instance of OrcSplit and the flags contain hasBase or deltas then it's
definitely ACID.
Else fallback to configuration object/table property.
@param conf
@param inputSplit
@return
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcInputFormat.java