Re: [Jython-users] Performance of urlparse.unquote / string slicing

[olivier m. <ome...@gm...>]

As jython is java why not using
String result = java.net.URLDecoder.decode(url, "UTF-8");
In your code ?


Le jeu. 10 déc. 2015 04:44, Toby Collett <Tob...@cr...> a écrit :

> Hi all,
> I have been investigating a performance issue with a large data chunk
> being sent via an http POST request. The outcome of which is that the
> bottleneck seems to be in urlparse.unquote. The data is about 6MB of XML,
> which takes in the order of 10 mins to run through urlparse.unquote(). This
> occurs in seconds in the cPython implementation.
>
> The performance difference seems to come down to slicing performance...For
> reference the unquote code is included below
> def unquote(s):
>     """unquote('abc%20def') -> 'abc def'."""
>     res = s.split('%')
>     # fastpath
>     if len(res) == 1:
>         return s
>     s = res[0]
>     for item in res[1:]:
>         try:
>             s += _hextochr[item[:2]] + item[2:]
>         except KeyError:
>             s += '%' + item
>         except UnicodeDecodeError:
>             s += unichr(int(item[:2], 16)) + item[2:]
>     return s
>
> To investigate the slicing performance I ran some simple test code through
> jython and python, timing is very adhoc (no efforts made to ensure same
> level of background activity etc, but the magnitude of the difference is
> large (3 times or more), and it is even more obvious when running the full
> unquote code.
>
> Is this the expected performance of jython slicing, or is there something
> that can be improved?
>
> Regards,
> Toby
>
> The test code
> ======
> import time
> for x in range(4,7):
>     start = time.time()
>     print x
>     len([b[:2] + b[2:] for b in  [u'%3casdf%3effff']*10**x])
>     print time.time() - start
> =======
> results
> $ python /tmp/a.py
> 4
> 0.00148105621338
> 5
> 0.0163309574127
> 6
> 0.152363061905
>
> $ jython /tmp/a.py
> 4
> 0.0190000534058
> 5
> 0.0709998607635
> 6
> 0.469000101089
>
>
>
>
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