[ python-Bugs-1209324 ] longs should be pickled in hexadecimal

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Bugs item #1209324, was opened at 2005-05-26 13:58
Message generated for change (Comment added) made by tim_one
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Category: Python Library
Group: None
Status: Closed
Resolution: Wont Fix
Priority: 5
Submitted By: Fredrik Johansson (fredrik_j)
Assigned to: Nobody/Anonymous (nobody)
Summary: longs should be pickled in hexadecimal

Initial Comment:
Longs are currently pickled to their decimal
representation. However, converting a very large number
represented in a binary base (used by Python longs) to
decimal is inefficient.

For example, the operation pickle.dumps(123**100001)
takes 50 seconds on my computer. The hexadecimal
representation of the same number, via hex(), can be
computed in an instant.

The hexadecimal representation also has the benefit of
being more concise.

I therefore suggest that the pickle format is changed
so that pickled longs are represented in hexadecimal.

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>Comment By: Tim Peters (tim_one)
Date: 2005-05-26 14:57

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More precisely, use pickle protocol 2 (or higher, although 2 is 
as high is it goes so far).  In pickle protocol 1 (which used to 
be called "binary"), and in protocol 0 (which used to be 
called "text") pickling and unpickling longs were still 
quadratic-time operations.

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Comment By: Raymond Hettinger (rhettinger)
Date: 2005-05-26 14:17

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Rather than introduce a backwards incompatible change, just
use binary pickles:  pickle.dumps(123**100001, 2).


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