Alex, In short, no, you can't create custom types through schemas. Schemas currently only refer to Riak Search 2.
We would love that too, but it hasn't happened yet. The problem is not conceiving of a data type but making its behavior both sensible and convergent in the face of concurrent activity or network partitions. For instance, say that two tweets come in around the same time. Who goes first in the "stack" you described? How can multiple independent copies reason about which ones to drop from the bottom of the stack to keep it bounded to 100? What happens if a replica is separated from the others for a while and has really stale entries, is it valid to serve those to a user? What happens when one replica pushes an element and another one pops it at the same time? These sound like they might be trivial problems, but they are incredibly hard to reason about in the general case. You have to reason about the ordering of events, the scope of their effects, and decide on a least-surprising behavior to expose to the user. Although we have given a pretty familiar/friendly interface to the data types shipping in 2.0, their behavior is strictly different from the types you would use in a single-threaded program in local memory. On Thu, Aug 28, 2014 at 4:47 PM, Alex De la rosa <alex.rosa....@gmail.com> wrote: > Hi there, > > Correct me if I'm wrong, but I think I read somewhere that custom data-types > can be created through schemas or something like that. So, apart from > COUNTERS, SETS and MAPS we could have some custom defined ones. > > I would love to have a STACKS data-type that would work like a FIFO stack, > so I could save the last 100 objects for some action. Imagine we are > building Twitter where millions of tweets are sent all the time, but we want > to quickly know the last 100 tweets for a user. Imagine something like: > > obj.stacks['last_tweets'].add(id_of_last_tweet) > > IN: last_tweet ---> STACK_OF_100_TWEETS ---> OUT: older than the 100th goes > out > > Is this possible? If so, how to do it? > > Thanks and Best Regards, > Alex > > _______________________________________________ > riak-users mailing list > riak-users@lists.basho.com > http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com > -- Sean Cribbs <s...@basho.com> Software Engineer Basho Technologies, Inc. http://basho.com/ _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
