Forward Partitioning & same Parallelism: 1:1 communication?

Posted by Nicaz on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/Forward-Partitioning-same-Parallelism-1-1-communication-tp2373.html

Hello,

I have a question about forward partitioning in Flink.

If Operator A and Operator B have the same parallelism set and forward partitioning is used for events coming from instances of A and going to instances of B:

Will each instance of A send events to _exactly one_ instance of B?

That is, will all events coming from a specific instance of A go to the _same_ specific instance of B, and will _all_ instances of B be used?
Or are there any situations where an instance of A will distribute events to several different instances of B, or where two instances of A will send events to the same instance of B (possibly leaving some other instance of B unused)?

I'd be very happy if someone were able to shed some light on this issue. :-)

Thanks in advance
Nica