Message225006
I think I have found a small typo-bug in tarfile.py, that seems to
be present in cpython upstream, which makes tarfile compression slower.
The issue can be seen here, in line 415 [1] of tarfile.py:
self.cmp = self.zlib.compressobj(9, self.zlib.DEFLATED,
-self.zlib.MAX_WBITS,
self.zlib.DEF_MEM_LEVEL,
0)
The minus sign doesn't make sense to me, because zlib.MAX_WBITS is 15,
and according to the documentation [2] wbits is by default 15 and
"This should be an integer from 8 to 15. Higher values give better
compression, but use more memory". -15 is not even in range. So I guess the expected value should be the zlib default, 15. Or maybe another value, but it should at least be in range.
I marked it as "performance" type bug as this only really affects performance.
I might have gotten it all wrong and it's fine the way it is, but I thought it'd be best to report it, as it looked fishy to me.
--
[1] http://hg.python.org/cpython/file/94d0e842b9ea/Lib/tarfile.py#l415
[2] https://docs.python.org/3.4/library/zlib.html#zlib.compressobj |
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Date |
User |
Action |
Args |
2014-08-07 11:02:32 | edulix | set | recipients:
+ edulix |
2014-08-07 11:02:32 | edulix | set | messageid: <1407409352.24.0.421737248606.issue22163@psf.upfronthosting.co.za> |
2014-08-07 11:02:32 | edulix | link | issue22163 messages |
2014-08-07 11:02:31 | edulix | create | |
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