Can't find docs/tutorial on secondary indexes for riak-erlang-client

Mark Phillips mark at basho.com
Mon Mar 12 01:26:57 EDT 2012


Hi Buriwoy,

Sorry for the hassle with the docs. Good to hear you're up and running. I scanned the thread really quickly and it didn't look like you mentioned 

http://wiki.basho.com/Secondary-Indexes.html

Assuming you've seen them, can you take 15 minutes and put together your thoughts on how to improve them in a wiki issue [1]. It shouldn't take anyone nearly this long to get up and running with any component of Riak. Our fault. Appreciate your help with fixing it. 

Mark

1 - https://github.com/basho/riak_wiki/issues/new

On Mar 11, 2012, at 18:48, Buri Arslon <buriwoy at gmail.com> wrote:

> After several hours of searching, trying, getting errors ... finally I was able to insert secondary index with riak-erlang-client. Here is the code which I successfully ran:
> 
>       %% Set some vars
>    {Bucket, Key, Index} = {<<"test_users">>, <<"aldarkusa">>, [{"qayerda_bin", "Qozoqta"}]}.
> 
>    %% Connect to riak
>    {ok, Pid} = riakc_pb_socket:start_link("127.0.0.1", 8087).
> 
>    %% Create a new riak object
>    Obj = riakc_obj:new(Bucket, Key, <<"Yomonlarni aldap yurgan Aldarkusa">>).
> 
>    %% Create a new metadata with secondary index
>    Meta = dict:store(<<"index">>, Index, dict:new()).
> 
>    %% Update the object we've created before
>    NewObj = riakc_obj:update_metadata(Obj, Meta).
> 
>    %% Finally, put/insert the updated new object
>    riakc_pb_socket:put(Pid, NewObj).
> 
> 
> I think Basho should update/improve the documentation. Examples in Links page (http://wiki.basho.com/Links.html) gave me some clues how to update metadata but the examples themselves were outdated.
> 
> Another idea is to allow users to post their examples (community content).
> 
> Regards,
> -- Buriwoy
> 
> On Sun, Mar 11, 2012 at 4:14 PM, Buri Arslon <buriwoy at gmail.com> wrote:
> I have some clue how to add secondary index but data types are confusing for me:
> 
>   > ObjNew = riakc_obj:new(<<"test_users">>, <<"adm">>, <<"My value">>).
>   > Index = [ <<"field1_bin">>, <<"my_index">>].
>   > Meta = dict:store(<<"index">>, Index, dict:new()).
>   > ObjNewMeta = riakc_obj:update_metadata(ObjNew, Meta).
>   > riakc_pb_socket:put(Pid, ObjNewMeta). 
>      ** exception exit: {noproc,
>                        {gen_server,call,
>                            [<0.124.0>,
>                             {req,
>                                 {rpbputreq,<<"test_users">>,<<"adm">>,undefined,
>                                     {rpbcontent,<<"My value">>,undefined,undefined,
>                                         undefined,undefined,undefined,undefined,undefined,undefined,
>                                         [{rpbpair,<<"field"...>>,[...]}]},
>                                     undefined,undefined,undefined,undefined,undefined,undefined,
>                                     undefined},
>                                 60000},
>                             infinity]}}
>       in function  gen_server:call/3 (gen_server.erl, line 188)
> 
> So, I don't know what the problem is. I can only guess that index data type may not be correct, but it's just guess. 
> 
> Any ideas?
> -- Buriwoy
> 
> On Sun, Mar 11, 2012 at 1:05 PM, Buri Arslon <buriwoy at gmail.com> wrote:
> Thanks for your reply Jeremiah!
> 
> I guess I am "greener" than you :) 
> 
> Before posting to the list, I looked through riak documentation, the list. I did find some postings on the subject but almost all of'em were questions than answers. The answers I could find were so ambiguous that I wasn't able to use them.
> 
> I've tried riakc_obj:update_metadata but got this error: http://dpaste.com/715011/
> 
> So, I hoped to find a working example. I'm too new to Erlang to read the source and solve my problems.
> 
> Thanks again,
> -- Buriwoy
> 
> 
> On Sun, Mar 11, 2012 at 12:46 PM, Jeremiah Peschka <jeremiah.peschka at gmail.com> wrote:
> Howdy Buri,
> 
> I'm not an Erlang expert, or even something remotely resembling competent with Erlang, however, I believe I have tracked down what you're looking for.
> 
> You can use one of the riakc_pb_socket:get_index functions to pull back data from an index. If you look at the source on the methods, you'll see that they're just wrappers around a MapReduce call. As far as setting the values... I think you'll have to make a call to riakc_obj:update_metadata and add the index metadata in by hand, but I could be wrong on that one.
> 
> If I'm wrong, hopefully someone on the list will correct my Erlang-y ignorance.
> 
> get_index/4 [1]
> get_index/5 [3]
> get_index/6 [2]
> get_index/7 [4]
> 
> 
> 
> [1]: https://github.com/basho/riak-erlang-client/blob/master/src/riakc_pb_socket.erl#L677
> [2]: https://github.com/basho/riak-erlang-client/blob/master/src/riakc_pb_socket.erl#L695
> [3]: https://github.com/basho/riak-erlang-client/blob/master/src/riakc_pb_socket.erl#L714
> [4]: https://github.com/basho/riak-erlang-client/blob/master/src/riakc_pb_socket.erl#L732
> ---
> Jeremiah Peschka - Managing Director, Brent Ozar PLF, LLC
> Microsoft SQL Server MVP
> 
> On Mar 11, 2012, at 11:06 AM, Buri Arslon wrote:
> 
> > Hi everybody,
> >
> > I can't find any tutorial or docs on secondary indexes. Here (http://lists.basho.com/pipermail/riak-users_lists.basho.com/2011-October/005952.html) it was stated that the docs would be updated but I can't find it.
> >
> > I just wanted a doc which explains how to use secondary indexes with native erlang client. Riak docs have examples for http api but not for erlang client.
> >
> > Can anyone refer me to appropriate docs/tutorials?
> >
> > Thanks,
> > -- Buriwoy
> > _______________________________________________
> > 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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