def count(model, limit):
result = model.count(limit)
if limit > 1000 and result == 1000:
result = len(model.all(keys_only=True).fetch(limit))
return result
----------
keakon
2010/4/10 Patrick Twohig <[email protected]>:
> I can't use a cursor, it has to happen in one request. I tried using a
> sharded counter to provide an estimation of ranking, but that has proven
> unsuccessful.
>
> On Thu, Apr 8, 2010 at 11:55 PM, Tim Hoffman <[email protected]> wrote:
>>
>> Hi
>>
>> You will need to use a cursor combined with a keys_only query (for
>> efficiency) and keep
>> resubmitting the cursor until you get all the results.
>>
>> If you plan to do this in appengine process rather than via the
>> remote_api you will probably need to use a chain of tasks
>> to achieve the result if you have a lot of entities.
>>
>> In python it looks something like the following (I don't do any work
>> with java on app engine)
>>
>> def count(query):
>> i = 0
>> while True:
>> result = query.fetch(1000)
>> i = i + len(result)
>> if len(result) < 1000:
>> break
>> cursor = query.cursor()
>> query.with_cursor(cursor)
>> return i
>>
>> myquery = mymodels.MyModel.all(keys_only=True)
>>
>> x = count(myquery)
>>
>> Hope this helps
>>
>> Rgds
>>
>> T
>>
>>
>> On Apr 9, 7:36 am, Patrick Twohig <[email protected]> wrote:
>> > I'm trying to figure out a way to count entities matching a certain
>> > criteria. I was thinking of doing a key-only query and using
>> > PreparedQuery.countEntities() (Java). However, when I do that, it
>> > always
>> > returns a value no higher than 1000. Is there a way to get an accurate
>> > count of all entities matching a query without having to do something
>> > like....
>> >
>> > int count = datastore.prepare( query.setKeysOnly()
>> > ).asList(FetchOptions.Builder.limit(Integer.MAX_VALUE)).size() ?
>> >
>> > Thanks,
>> > Patrick.
>> >
>> > --
>> > Patrick H. Twohig.
>> >
>> > Namazu Studios
>> > P.O. Box 34161
>> > San Diego, CA 92163-4161
>> >
>> > --
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>>
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>
>
>
> --
> Patrick H. Twohig.
>
> Namazu Studios
> P.O. Box 34161
> San Diego, CA 92163-4161
>
> --
> You received this message because you are subscribed to the Google Groups
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>
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