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Re: Hash stability

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Heiko Wundram wrote:

> Am 15.01.2012 13:22, schrieb Peter Otten:

>> I'm curious: did you actually get false cache hits 

in a suds cache

>> or just slower responses?

> It broke the application using suds, not due to false cache hits, but
> due to not getting a cache hit anymore at all.

> so basically I worked around
> the problem by creating an appropriate cache entry with the appropriate
> name based on hash() using a local copy of xml.dtd I had around. This
> took place on a development machine (32-bit), and when migrating the
> application to a production machine (64-bit), the cache file wasn't used
> anymore (due to the hash not being stable).

Thanks for the explanation.

> if the hash() output is changed. Additionally, if hash() isn't stable
> between runs (the randomized hash() solution which is preferred, and
> would also be my preference), suds caching becomes completely useless.
> And for the results, see above.

I've taken a quick look into the suds source; the good news is that you have 
to change a single method, reader.Reader.mangle(), to fix the problem with 
hash stability. 

However, I didn't see any code to deal with hash collisions at all.

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Thread

Hash stability Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-01-14 04:42 +0000
  Re: Hash stability Peter Otten <__peter__@web.de> - 2012-01-14 10:46 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-14 23:45 +0100
  Re: Hash stability Chris Angelico <rosuav@gmail.com> - 2012-01-15 11:36 +1100
    Re: Hash stability Bryan <bryanjugglercryptographer@yahoo.com> - 2012-01-15 04:03 -0800
      Re: Hash stability Chris Angelico <rosuav@gmail.com> - 2012-01-15 23:21 +1100
  Re: Hash stability Roy Smith <roy@panix.com> - 2012-01-14 21:26 -0500
    Re: Hash stability Terry Reedy <tjreedy@udel.edu> - 2012-01-14 23:07 -0500
  Re: Hash stability Stefan Behnel <stefan_ml@behnel.de> - 2012-01-15 11:13 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-15 12:46 +0100
  Re: Hash stability Peter Otten <__peter__@web.de> - 2012-01-15 13:22 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-15 17:07 +0100
  Re: Hash stability Chris Angelico <rosuav@gmail.com> - 2012-01-16 03:13 +1100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-15 17:51 +0100
  Re: Hash stability Stefan Behnel <stefan_ml@behnel.de> - 2012-01-15 18:20 +0100
  Re: Hash stability Peter Otten <__peter__@web.de> - 2012-01-16 09:18 +0100
  Re: Hash stability Christian Heimes <lists@cheimes.de> - 2012-01-16 09:44 +0100
  Re: Hash stability Heiko Wundram <modelnine@modelnine.org> - 2012-01-16 10:15 +0100

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