querying riak

Justin Sheehy justin at basho.com
Mon Nov 30 09:03:10 EST 2009

Hi Francisco,

On Thu, Nov 12, 2009 at 7:15 AM, francisco treacy
<francisco.treacy at gmail.com> wrote:

> I read doc/basic-mapreduce.txt  but I still can't grasp the
> possiblities of querying, mainly due to my lack of Erlang knowledge.
> >From what I can imagine, once the Map/Reduce functionality is exposed
> through HTTP,  functions written in Javascript (ala CouchDB), but with
> dynamic queries (ala MongoDB) will be possible. Is this correct?

That is a reasonable way of describing it, yes.  The map/reduce
functionality of Riak will be exposed fully over HTTP and programmable
fully in JavaScript.  It will remain in its current model of a
programming interface and not a view engine; you execute targeted
map/reduce chains and they produce results, not persistent views.

You will be able to send your map/reduce functions to Riak via HTTP
and you will also receive the results over HTTP.  The form of the
contents of the results will depend on the functions you execute in
your map and reduce functions.  Note also that in Riak map/reduce is
not a simple two-phase process, but consists of an arbitrary number
and ordering of map phases and reduce phases chosen by the programmer.

> Does this mean that the querying feature will be only on a
> non-open-source, paid product?

We intend for the basic indexing (and querying of those indices) to
make it into the open source trunk of Riak, with some additional
search-related features in the paid product.

> Partly because I haven't found documentation.

Documentation that exists before the code it describes is likely to
become out of date very quickly.  As these features develop, we will
be sure to get the word out on how to use them.



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