Problem with keys filter in erlang pb client

Question

UPDATE2 I found the solution (thx to rvirding). I have to put object like this

Object = riakc_obj:new(list_to_binary(Bucket),
                       list_to_binary(Time),
                       list_to_binary(TimeValue)),
ok = riakc_pb_socket:put(Db_pid, Object);

And make the request like this

Query = [{map,                                                  %query type
             {modfun, riak_kv_mapreduce, map_object_value},         %function from riak erlang built-in module
             none, true}],
    Inputs = {Bucket, [[<<"between">>, <<"0">>, <<"0.05">>]]},
    Result = riakc_pb_socket:mapred(Pid, Inputs, Query),

I think It should be mentioned in docs.

BTW! If I wrote

Object = riakc_obj:new(<<Bucket>>,
               <<Time>>,
               <<TimeValue>>),

I got en error about badarg. Still confused about this.(

UPDATE

If I write this

Inputs = {Bucket, [[<<"between">>, 0, 1]]}

I got no error, I even got "ok" result, but it is empty, which is not expected behavior.)

===============================================================

I totally lost my mind with this, but I have to finish it.

I have simple app: it extracts data from txt file (data like "timestamp value"), push it to Riak and make some range queries. The problem is when I make key filter query I get {error,disconnected}. I strore data in riak in this way: key – timestamp (like 0.43), value – value (like 1.14), bucket – time of adding data (like "2011-07-24-23-39-45"). Here's the code of request:

(dca_db.erl)

handle_call({range_query, Bucket, From, To}, _, #state{db_pid = Pid} = State) ->
    Query = [{map,                                                  %query type
             {modfun, riak_kv_mapreduce, map_object_value},         %function from riak erlang built-in module
             none, true}],
    Inputs = {Bucket, [["between", 0, 1]]},
    Result = riakc_pb_socket:mapred(Pid, Inputs, Query),
    {reply, Result, State};

(test/dca_db_tests.erl)

range_request(Pid) ->
Bucket = <<"2011-07-24-23-39-45">>,
Result = gen_server:call(Pid, {range_query, Bucket, 0, 1}),
error_logger:info_msg("RESULT:~p~n",[Result]).

You can find my code in github – https://github.com/DimitryDushkin/distributed_calc_riak_matlab

If I use something like (in dca_db.erl)

Inputs = {Bucket, [["eq", 1]]},

I have another error

Compiled src/dca_db.erl
undefined
*unexpected termination of test process*
::{{badmatch,{<<"2011-07-24-23-39-45">>,[["eq",1]]}},
   [{dca_db,handle_call,3},
    {gen_server,handle_msg,5},
    {proc_lib,init_p_do_apply,3}]}


=ERROR REPORT==== 25-Jul-2011::00:27:24 ===
** Generic server dca_db terminating 
** Last message in was {range_query,<<"2011-07-24-23-39-45">>,0,1}
** When Server state == {state,<0.105.0>}
** Reason for termination == 
** {{badmatch,{<<"2011-07-24-23-39-45">>,[["eq",1]]}},
    [{dca_db,handle_call,3},
     {gen_server,handle_msg,5},
     {proc_lib,init_p_do_apply,3}]}
=======================================================
  Failed: 0.  Skipped: 0.  Passed: 1.
One or more tests were cancelled.
Cover analysis: /Users/ddushkin/Documents/workspaces/eclipse/distributed_calc_riak_matlab/.eunit/index.html
ERROR: One or more eunit tests failed.
make: *** [test_db] Error 1

And everything works if I do not use filters:

Inputs = Bucket,

Thank you.

Answer 1

The bucket and keys to riak should be binaries, that is why you get no error. That you are not finding anything means that the bucket/keys are wrong. How were they created when data was added to the DB? Make sure you do it exactly the same way! In an app I have worked with they did term_to_binary(Key) for the value but it can be done in any way you choose.