Alway return 21 when describe collection

[huuson235]

CMD: describe collection -c col
Return: 21
Schema below

fields = [
    FieldSchema(name="id", dtype=DataType.INT64, is_primary=True, auto_id=True),
    FieldSchema(name="image_url", dtype=DataType.VARCHAR, max_length=MAX_LENGTH_URL),
    FieldSchema(name="customer_code", dtype=DataType.VARCHAR, max_length=MAX_LENGTH_C_CODE),
    FieldSchema(name="embedding", dtype=DataType.FLOAT_VECTOR, dim=512),
    FieldSchema(name="created_at_raw", dtype=DataType.VARCHAR, max_length=20),
    FieldSchema(name="created_at", dtype=DataType.INT64),
]

schema = CollectionSchema(fields, "Database")