If I understand you correctly, you want to write something like: ------------------------------------------------------------------
[cassandra] ^ | V (event source) ----> (Add event and lookup) ---> (further ops) ------------------------------------------------------------------ That should work with Flink, yes. You can communicate with an external Cassandra service inside functions. We are also working on making larger-than-memory state easily supported in Flink, so future versions may allow you to do this without any external service. On Thu, Dec 17, 2015 at 8:54 AM, igor.berman <igor.ber...@gmail.com> wrote: > Hi, > We are looking at Flink and trying to understand if our usecase is relevant > to it. > > We need process stream of events. Each event is for some id(e.g. device > id), > when each event should be > 1. stored in some persistent storage(e.g. cassandra) > 2. previously persisted events should be fetched and some computation over > whole history may or may not trigger some other events(e.g. sending email) > > so yes we have stream of events, but we need persistent store(aka external > service) in the middle > and there is no aggregation of those events into something smaller which > could be stored in memory, i.e. number of ids might be huge and previous > history of events per each id can be considerable so that no way to store > everything in memory > > I was wondering if akka stream is sort of optional solution too > > please share your ideas :) > thanks in advance, > Igor > > > > -- > View this message in context: > http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/Usecase-for-Flink-tp4076.html > Sent from the Apache Flink User Mailing List archive. mailing list archive > at Nabble.com. >