"Adam Olsen" <[EMAIL PROTECTED]> wrote: > On 9/4/06, Gustavo Carneiro <[EMAIL PROTECTED]> wrote: > > > Now, we've had this API for a long time already (at least 2.5 > > years). I'm pretty sure it works well enough on most *nix systems. > > Event if it works 99% of the times, it's way better than *failing* > > *100%* of the times, which is what happens now with Python. > > Failing 99% of the time is as bad as failing 100% of the time, if your > goal is to eliminate the short timeout on poll(). 1% is quite a lot, > and it would probably have an annoying tendency to trigger repeatedly > when the user does certain things (not reproducible by you of course).
That can make it a lot WORSE that repeated failure. At least with hard failures, you have some hope of tracking them down in a reasonable time. The problem with exception handling code that goes off very rarely, under non-reproducible circumstances, is that it is almost untestable and that bugs in it are positive nightmares. I have been inflicted with quite a large number in my time, and have a fairly good success rate, but the number of people who know the tricks is decreasing. Consider the (real) case where an unpredictable process on a large server (64 CPUs) was failing about twice a week (detectably), with no indication of how many failures were giving wrong answers. We replaced dozens of DIMMs, took days of down time and got nowhere; it then went hard (i.e. one failure a day). After a week's total down time, with me spending 100% of my time on it and the vendor allocating an expert at high priority, we cracked it. We were very lucky to find it so fast. I could give you other examples that were/are there years and decades later, because the pain threshhold never got high enough to dedicate the time (and the VERY few people with experience). I know of at least one such problem in generic TCP/IP (i.e. on Linux, IRIX, AIX and possibly Solaris) that has been there for decades and causes occasional failure in most networked applications/protocols. Regards, Nick Maclaren, University of Cambridge Computing Service, New Museums Site, Pembroke Street, Cambridge CB2 3QH, England. Email: [EMAIL PROTECTED] Tel.: +44 1223 334761 Fax: +44 1223 334679 _______________________________________________ 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
