try {
DataInputStream input = new DataInputStream(stream);
int arrayKVRefSize = WritableUtils.readVInt(input);
for (int i = 0; i < arrayKVRefSize; i++) {
KeyValueColumnExpression kvExp = new KeyValueColumnExpression();
kvExp.readFields(input);
arrayKVRefs.add(kvExp);
}
int arrayKVFuncSize = WritableUtils.readVInt(input);
Expression[] arrayFuncRefs = new Expression[arrayKVFuncSize];
for (int i = 0; i < arrayKVFuncSize; i++) {