On 17 Oct 2013, at 17:21, Jeremiah Peschka <jeremiah.pesc...@gmail.com> wrote:
> When you 'update' a counter, you send in an increment operation. That's added > to an internal list in Riak. The operations are then zipped up to provide the > correct counter value on read. The worst that you'll do is add a large(ish) > number of values to the op list inside Riak. Just to borrow some Cribbs-brand pedantry here:- That isn't true. We read the data from disk, increment an entry in what is essentially a version vector, and write it back, (then replicate the result to N-1 vnodes.) The size of the counter depends on the number of actors that have incremented it (typically N) not the number of operations. > > Siblings will be created, but they will not be visible to the end user who is > reading from the counter. There won't be siblings on disk (we do create a temporary one in memory, does that count?) _unless_ 1. you also write an object to that same key in a normal riak kv way (don't do that) 2. AAE or MDC cause a sibling to be created (this is because we use the operation of incrementing a counter to identify a key as counter, to the rest of riak it is just a riak object) In that last case, an increment operation to the key will resolve the sibling(s). Cheers Russell > > Check out this demo of the new counter types from Sean Cribbs: > https://vimeo.com/43903960 > > --- > Jeremiah Peschka - Founder, Brent Ozar Unlimited > MCITP: SQL Server 2008, MVP > Cloudera Certified Developer for Apache Hadoop > > > On Thu, Oct 17, 2013 at 9:55 AM, Daniil Churikov <ddo...@gmail.com> wrote: > Correct me if I wrong, but when you blindly do update without previous read, > you create a sibling, which should be resolved on read. In case if you make > a lot of increments for counter and rarely reads it will lead to siblings > explosion. > > I am not familiar with new counters datatypes, so I am curious. > > > > -- > View this message in context: > http://riak-users.197444.n3.nabble.com/Read-Before-Writes-on-Distributed-Counters-tp4029492p4029498.html > Sent from the Riak Users mailing list archive at Nabble.com. > > _______________________________________________ > 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 _______________________________________________ riak-users mailing list riak-users@lists.basho.com http://lists.basho.com/mailman/listinfo/riak-users_lists.basho.com
