Hey Shedokan,
Are you fetching your files from Datastore in a batch, or one at a time?
data = []
for filename in ['a', 'b', 'c']:
data.append(SomeModel.get_by_key_name(filename))
Is significantly slower than:
keys = [ db.Key.from_path('SomeModel', fn) for fn in [ 'a', 'b', 'c' ] ]
data = db.get(keys)
2009/5/29 Shedokan <shedok...@gmail.com>:
>
> Thanks, I am worried because I am trying to optimize my app to be
> almost as fast as the php version.
>
> usualy it takes 250ms for an ajax request(firebug) in the php version
> and 500ms in the python version so python is two times slower than the
> php version.
> but I guess it's because I have to store the files in the datastore
> and not in real directories.
>
> well thanks anyway.
>
> On 29 מאי, 04:32, David Wilson <d...@botanicus.net> wrote:
>> Just assume that any string/list/hash/integer-related operations in
>> Python are likely faster than you'll ever need them to be. The
>> overhead for buffering the response is going to be tiny regardless of
>> your application, since at most you're only talking about handling
>> strings of up to 10mb (which is the request size limit).
>>
>> If there is anything with AppEngine you need to be careful of, it is
>> use of Datastore, where reading/writing large numbers of entities will
>> cost a lot of performance. Reducing your Datastore use by a single
>> db.get() is equal to thousands of calls to self.response.out.write()
>>
>> $ python /usr/lib/python2.5/timeit.py -v -s 'from cStringIO import
>> StringIO; out = StringIO()' 'out.write("123")'
>> 10000 loops -> 0.00373 secs
>> 100000 loops -> 0.0383 secs
>> 1000000 loops -> 0.365 secs
>> raw times: 0.358 0.358 0.357
>> 1000000 loops, best of 3: 0.357 usec per loop
>>
>> $ ae
>> Python 2.5.1 (r251:54863, Feb 6 2009, 19:02:12)
>> [GCC 4.0.1 (Apple Inc. build 5465)] on darwin
>> Type "help", "copyright", "credits" or "license" for more information.
>> (AppEngineShell)>>> import time
>> >>> t1 = time.time() ; db.get(db.Key.from_path('Foo', 1234)) ; print
>> >>> (time.time()-t1)*1000
>>
>> 12.0000839233
>>
>> David.
>>
>> 2009/5/29 Shedokan <shedok...@gmail.com>:
>>
>>
>>
>>
>>
>>
>>
>> > Thanks, but does self.response.out affects speed very much?
>> > I couldn't benchmark it, strange...
>>
>> > On 28 מאי, 22:25, David Wilson <d...@botanicus.net> wrote:
>> >> Using self.response.out will also delay sending your entire response
>> >> until it is sure to succeed.
>>
>> >> If you start generating output using 'print', and then e.g. a
>> >> Datastore request times out, or a bug in your code is triggered, you
>> >> have no chance to display a friendly error message. Instead the user
>> >> will get a half-rendered page with a stack trace embedded in it, or
>> >> worse.
>>
>> >> David.
>>
>> >> 2009/5/28 Shedokan <shedok...@gmail.com>:
>>
>> >> > so I can't print binary data like Images?
>>
>> >> > On 28 מאי, 21:03, 风笑雪 <kea...@gmail.com> wrote:
>> >> >> Print is also OK, but you need handle header by yourself, and it can
>> >> >> only
>> >> >> output
>> >> >> text.http://code.google.com/intl/en/appengine/docs/python/gettingstarted/h...
>>
>> >> >> print 'Content-Type: text/plain'
>> >> >> print ''
>> >> >> print 'Hello, world!'
>>
>> >> >> 2009/5/29 Shedokan <shedok...@gmail.com>
>>
>> >> >> > I am wondering why should I use self.response.out.write and not print
>> >> >> > everything.
>>
>> >> >> > because I am making this app where I have to output from a lot
>> >> >> > ofdifferent functions and I am passing the object 'self' everywhere.
>>
>> >> >> > thanks.
>>
>> >> --
>> >> It is better to be wrong than to be vague.
>> >> — Freeman Dyson
>>
>> --
>> It is better to be wrong than to be vague.
>> — Freeman Dyson
> >
>
--
It is better to be wrong than to be vague.
— Freeman Dyson
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