Hi Justin, Thanks for the feedback. Just thought I'd mention we're aiming to go ahead with a strategy of serialising the transactions before they hit Riak. We figure it'll be easier to solve than trying to do conflict resolution.
Cheers, --Misha On 14 July 2010 14:00, Justin Sheehy <jus...@basho.com> wrote: > On Wed, Jul 14, 2010 at 5:25 AM, Misha Gorodnitzky <mis...@pobox.com> wrote: > >> I don't suppose there are any examples anywhere of how people have >> approached conflict resolution with RIak? That would be useful to help >> people understand how to approach it ... maybe a section on the wiki >> could be dedicated to it. > > This is a great idea. We'll find a right place to present this that's > easier to find. > >> In our particular case, we're trying to store transactions in Riak and >> need to guard against a transaction being placed on a balance that has >> reached 0. The problem we keep running into is race conditions between >> when we record the transaction and when we update the cached balance >> value. Any suggestions on how this has been, or can, be solved would >> be appreciated. > > I suggest that you solve this similarly to the way that banks have > been doing so for far longer than there have even been computers > involved. Each transaction should be (at least) a unique identifier, > a time, and the amount being added or subtracted to the balance. This > way (in addition to storing what you believe the balance to be at any > time) you can reconcile balances even if you get some transactions > late or multiple times. > > More specifics than that will depend a lot on your application, but > the key here is that you can make things much neater in situations > where your actions can be commutative and idempotent. That's why you > store the transaction itself instead of just the balance, and a unique > id so that you don't repeat yourself. > > Best of luck, > > -Justin > _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
