On 2/20/07, Raymond Hettinger <[EMAIL PROTECTED]> wrote: > After thinking more about Py_ssize_t, I'm surprised that we're not hearing > about > 64 bit users having a couple of major problems. > > If I'm understanding what was done for dictionaries, the hash table can grow > larger than the range of hash values. Accordingly, I would expect large > dictionaries to have an unacceptably large number of collisions. OTOH, we > haven't heard a single complaint, so perhaps my understanding is off.
Not until the has table has 4 billion entries. I believe that would be 96 GB just for the hash table; plus probably at least that for that many unique key strings. Not to mention the values (but those needn't be unique). I think the benefit of 64-bit architecture start above using 2 or 3 GB of RAM, so there's quite a bit of expansion space for 64-bit users before they run into this theoretical problem. > The other area where I expected to hear wailing and gnashing of teeth is users > compiling with third-party extensions that haven't been updated to a > Py_ssize_t > API and still use longs. I would have expected some instability due to the > size > mismatches in function signatures -- the difference would only show-up with > giant sized data structures -- the bigger they are, the harder they fall. > OTOH, > there have not been any compliants either -- I would have expected someone to > submit a patch to pyport.h that allowed a #define to force Py_ssize_t back to > a > long so that the poster could make a reliable build that included non-updated > third-party extensions. > > In the absence of a bug report, it's hard to know whether there is a real > problem. Have all major third-party extensions adopted Py_ssize_t or is some > divine force helping unconverted extensions work with converted Python code? > Maybe the datasets just haven't gotten big enough yet. My suspicion is that building Python for an 64-bit address space is still a somewhat academic exercise. I know we don't do this at Google (we switch to other languages long before the datasets become so large we'd need a 64-bit address space for Python). What's your experience at EWT? -- --Guido van Rossum (home page: http://www.python.org/~guido/) _______________________________________________ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
