KafkaStreams - impact of retention on repartition topics

[Murilo Tavares]

Hi
I have a complex KafkaStreams topology, where I have a bunch of KTables
that I regroup (rekeying) and aggregate so I can join them.
I've noticed that the "-repartition" topics created by the groupBy
operations have a very long retention by default (Long.MAX_VALUE).
I'm a bit concerned about the size of these topics, as they will retain
data forever. I wonder why are they so long, and what would be the impact
of reducing this retention?
Thanks
Murilo