There are issues in implementing support of request rate in robotparser.

    req_rate = collections.namedtuple('req_rate',
                                      'requests seconds')
    entry.req_rate = req_rate
    entry.req_rate.requests = int(numbers[0])
    entry.req_rate.seconds = int(numbers[1])

First, a new namedtuple type is created for every entry. This is slow even with recent namedtuple optimizations, and is much slower in 3.6. This wastes a memory, since new type is created for every entry. This is definitely wrong, since req_rate is set to a namedtuple type instead of namedtuple instance. And there is a question why a namedtuple is used here at all. Other classes in this module are not namedtuples.

Hey Serhiy,

The use of namedtuple was requested specifically at a review, I didn't implement it like this initially: https://bugs.python.org/review/16099/#ps6205

I wasn't aware of the performance implications. Could you please explain to me the type vs instance in terms of performance (or point me to a resource, a quick googling didn't yield anything? How was I supposed to have coded it properly?

Cheers,

Nick

For the performance of namedtuple type creation see issue28638 and https://mail.python.org/pipermail/python-dev/2017-July/148592.html. For difference between types and instance see https://docs.python.org/3/tutorial/classes.html.

Thanks for the report. Your analysis is correct and this is a duplicate of issue 31325. I'll take care of the PR 3259.

Oh, I missed this. My report is based on the same comment on news.ycombinator.com.

resolution: duplicate
stage: resolved