We use a technique that works well for our use case:
We store everything as JSON and use the erlang-client, for every object we
store we add an opaque schema_version tag to the JSON and then in our model
encode/decode routine we parse this schema_version and if the version is not
the latest according to the model we recurse and upgrade the payload all the
way up to the current version and then return the new object to the client and
spawn an async process that saves the new object back.
So for instance an object is at schema_version 1 when it get's read. The model
is now on version 5 there will be five functions, i.e:
upgrade_version(2, Payload) ->
do_something();
upgrade_version(3, Payload) ->
etc...
every function knows how to upgrade itself from it's former version so fast
forwarding through version is easy and every object will get upgraded
eventually (if the get read).
--
Bip Thelin
KIVRA | Lugnets Allé 1 | 120 33 Stockholm
Tel 08-533 335 37 | Mob 0735-18 18 90
www.kivra.com
On 19 sep 2012, at 00:55, Allen Johnson <akjohnso...@gmail.com> wrote:
> Hey everyone,
>
> I'm beginning to experiment with Riak and I'm trying to better
> understand how to model my data. One question I have at the moment is
> how to evolve my data with a data store such as Riak? I know that
> it's schema-less and that I can add new fields as needed but I'm
> thinking more about the existing documents.
>
> For example, say hypothetically, that I have a fairly successful
> riak-based app. As the application code continues to evolve over
> several versions I begin to find a "better" way to model my data. By
> this time I have already stored many, many documents. What is the
> appropriate path here? Do I version my documents with metadata and
> rely on my application code to continue to deal with old-style
> documents -- or do I perform some sort of bulk transformation on these
> existing documents?
>
> Thanks,
> Allen
>
> _______________________________________________
> riak-users mailing list
> riak-users@lists.basho.com
> http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
_______________________________________________
riak-users mailing list
riak-users@lists.basho.com
http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
