In addition : ProcessWindowFunction extends AbstractRichFunction, through getRuntimeContext，you can access keyed state API.
vino yang <yanghua1...@gmail.com> 于2018年9月10日周一 下午3:19写道： > Hi Ning, > > Answer you question: > > *And why is rich functions not allowed here?* > > If you need access to the state API, you can consider using > ProcessWindowFunction[1], which allows you to use ProcessWindowFunction. > > Thanks, vino. > > [1]: > https://ci.apache.org/projects/flink/flink-docs-release-1.6/dev/stream/operators/windows.html#processwindowfunction > > Ning Shi <nings...@gmail.com> 于2018年9月10日周一 上午11:28写道： > >> Since the aggregate() function on a keyed window stream does not allow >> using rich functions, I can only use an AggregateFunction. Is the >> accumulator state of the AggregateFunction backed by RocksDB and >> persisted in checkpoints if I use the RocksDB backend. My job looks >> like the following, >> >> sourceStream.keyBy(…) >> .timeWindow(Time.seconds(…)) >> .trigger(CountTrigger.of(…)) >> .aggregate(new MyAggFunc()); >> >> Since the stream has high cardinality keys, each window could have >> millions of them. If the accumulator state is not backed by RocksDB, >> there might be a lot of data stored on the heap. >> >> And why is rich functions not allowed here? >> >> Thanks, >> >> — >> Ning >> >
