Your observation is correct. The paragraph you quote is not very precise but also not necessarily wrong. The example is simplified and assumes that there is no re-partitioning even if it is not mentioned explicitly.
-Matthias On 6/20/17 9:32 AM, Paolo Patierno wrote: > Hi devs, > > > at following documentation page (by Confluent) I read > (http://docs.confluent.io/current/streams/architecture.html#stream-partitions-and-tasks) > ... > > > "the maximum parallelism at which your application may run is bounded by the > maximum number of stream tasks, which itself is determined by maximum number > of partitions of the input topic(s) the application is reading from. For > example, if your input topic has 5 partitions, then you can run up to 5 > applications instances" > > but it seems not so true ... I mean ... > The number of the application instances depends on the possibility that we > have "internal" repartition topic in our processor topology. > I tried the WordCountDemo starting from a topic with 2 partitions. In this > case I'm able to run up to 4 application instances while the 5th stays idle. > It's possible because due to the map() in the example we have repartitioning > (so 1 repartition topic with 2 partitions) ... it means 4 tasks for the total > 4 partitions (2 for the input topic, 2 for the repartition topic) ... and > this tasks can run even one for each application instance. > Following the above mentioned doc part the maximum should be just 2 (not 4). > > Do you confirm this ? > > Thanks, > Paolo > > > Paolo Patierno > Senior Software Engineer (IoT) @ Red Hat > Microsoft MVP on Windows Embedded & IoT > Microsoft Azure Advisor > > Twitter : @ppatierno<http://twitter.com/ppatierno> > Linkedin : paolopatierno<http://it.linkedin.com/in/paolopatierno> > Blog : DevExperience<http://paolopatierno.wordpress.com/> >
signature.asc
Description: OpenPGP digital signature
