usage : partitionPersist(StateFactory stateFactory, StateUpdater updater)

[Sun, Keith]

Hi ,

Thanks for your notice and I am new to Storm, so my question maybe a little 
stupid :(.

I run the Trident with "partitionPersist(StateFactory stateFactory, 
StateUpdater updater) "  :

            TridentTopology topology = new TridentTopology();
            topology.newStream("emitWord", spout).partitionBy(new 
Fields("word"))
            // .each(new Fields("word"), new C2CFilters.PrintFilter());
            //.partitionPersist(jdbcStateFactory, new Fields("word"), new 
MysqlStateUpdater(), new Fields("word")).parallelismHint(1);
            .partitionPersist(jdbcStateFactory,new 
JdbcUpdater()).parallelismHint(1);

I noticed the Input tuple to JdbcUpdater#updateState is always null and my 
process just aborted. I tried a few hours and finally noticed I have no input 
fields selector.

So , my question is what is the purpose of such method  ?


Thanks very much.
Keith