And of course, there's then the matter of the BOLT crashing and losing the state, unless you keep it in a separate store, and... you get the idea.
On Fri, Jul 3, 2015 at 2:20 PM, Javier Gonzalez <[email protected]> wrote: > You need to keep track of state in your bolt before writing. Yes, it is > indeed quite a chore. For "exactly once", particularly when coordinating > with external systems such as databases or output queues, Storm is, ah, not > exactly the best fit. Unless keeping track of processed events to avoid > duplication is feasible in your use case. > > Regards, > Javier > > On Fri, Jul 3, 2015 at 6:44 AM, jinhong lu <[email protected]> wrote: > >> Hi, >> >> I build a topo to get messages from by kafka, and then grep some >> keyword, if fit, write to local file. >> >> I use OpaqueTridentKafkaSpout of storm-kafka to ensure the tuple will not >> miss or repeate, but consider one situation: when writing message to local >> file, and some error occurse(for example, not enough space). At this >> moment, some messages have writen to local file, and others not, if the >> spout resend the message, the message will be write twice. >> >> how to do that?thanks. >> >> jinhong_lu >> > > > > -- > Javier González Nicolini > -- Javier González Nicolini
