Simple mapreduce with 2i returns different result

Mattias Sjölinder mattias at sjolinder.se
Wed Apr 17 06:55:55 EDT 2013


Ok, we got it. We have made a fix that is working for us handling the
result.

Thanks for your time and responses around this!

Regards,
Mattias


2013/4/17 OJ Reeves <oj at buffered.io>

> Hi guys,
>
> Russell is correct. In CI we gather the responses as they come in, in
> whichever order they're received. We make some effort to flatten the
> result, but we take the approach of being "smart enough to get you the
> results, but no smarter".
>
> We don't do anything to reorder or manage the results in the way that the
> HTTP interface does as we feel that's behaviour that the user of the
> library should decide to implement should they desire it.
>
> HTH.
> OJ
>
>
>
> On Wed, Apr 17, 2013 at 5:58 PM, Russell Brown <russell.brown at mac.com>wrote:
>
>>
>> On 17 Apr 2013, at 08:54, Mattias Sjölinder <mattias at sjolinder.se> wrote:
>>
>> > Thanks for your help. Your query returned the same number over and over
>> again just as expected.
>> >
>> > I think I have found the reason for my problem though. The client lib
>> CorrugatedIron seems to wrap each document in the MapReduce result into a
>> array turning the result into a nested array looking like:
>> > [[{doc1}], [{doc2}], [{doc3}]] counting 3 arrays & 3 docs
>> > and sometimes
>> > [[{doc1}], [{doc2}, {doc3}]] counting 2 arrays and 2 docs (according to
>> my client code... :)
>> >
>> > Why the result for same query in CorrugatedIron and for a simple curl
>> differs I don't know but I will investigate it further.
>>
>> My guess is the client library streams the mapreduce results and gathers
>> the separate messages. So depending on how many chunks are sent by riak you
>> get a different nested array of responses.
>>
>> >
>> >
>> > Thanks again for your help!
>> >
>> > Best regards,
>> > Mattias
>> >
>> >
>> >
>> > 2013/4/16 Christian Dahlqvist <christian at basho.com>
>> > Hi Mattias,
>> >
>> > The following curl query simply counts the number of inputs, and has
>> worked well for me in the past. Can you please run it against the cluster a
>> couple of times and see if it also return varying number of results?
>> >
>> > curl -XPOST http://localhost:8098/mapred
>> >   -H 'Content-Type: application/json'
>> >   -d '{"inputs":{
>> >            "bucket":"som-bucket",
>> >            "index":"userid_bin",
>> >            "key":"18481123123"
>> >        },
>> >        "query":[{"reduce":{"language":"erlang",
>> >                            "module":"riak_kv_mapreduce",
>> >                            "function":"reduce_count_inputs"
>> >                            }}]}'
>> >
>> > Best regards,
>> >
>> > Christian
>> >
>> >
>> >
>> >
>> >
>> > On 16 Apr 2013, at 15:52, Mattias Sjölinder <mattias at sjolinder.se>
>> wrote:
>> >
>> >> 18481123123
>> >
>> >
>> > _______________________________________________
>> > riak-users mailing list
>> > riak-users at lists.basho.com
>> > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
>>
>>
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>
>
>
> --
>
> OJ Reeves
> +61 431 952 586
> http://buffered.io/
>
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