@Override
public void readFields(DataInput input) throws IOException {
super.readFields(input);
toType = PDataType.values()[WritableUtils.readVInt(input)];
toMod = ColumnModifier.fromSystemValue(WritableUtils.readVInt(input));
int byteSize = WritableUtils.readVInt(input);
this.byteSize = byteSize == -1 ? null : byteSize;
}
