2017年10月02日 13:10 GMT+02:00 INADA Naoki <[email protected]>: > https://github.com/python/cpython/pull/3796 > In this PR, lazy loading only happens when uuid1 is used. > But uuid1 is very uncommon for nowdays.
Antoine Pitrou added a new C extension _uuid which is imported as soon as uuid(.py) is imported. On Linux at least, the main "overhead" is still done on "import uuid". But Antoine change optimized a lot "import uuid" import time! > https://github.com/python/cpython/pull/3757 > In this PR, singledispatch is lazy loading types and weakref. > But singledispatch is used as decorator. > So if web application uses singledispatch, it's loaded before preforking. While "import module" is fast, maybe we should use sometimes a global variable to cache the import. module = None def func(): global module if module is None: import module ... I'm not sure that it's possible to write an helper for such pattern. In *this case*, it's ok, since @singledispatch is more designed to be used with top-level functions, not on nested functions. So the overhead is only at startup, not at runtime in practice. > Maybe, copying `tokenize.open()` into linecache is better than lazy loading > tokenize. Please don't copy code, only do that if we have no other choice. > Anyway, I completely agree with you; we should careful enough about lazy > (importing | compiling). I think that most core devs are aware of tradeoffs and we try to find a compromise on a case by case basis. Victor _______________________________________________ Python-Dev mailing list [email protected] https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com