Hi Michał, Internally, Kafka uses "*consumer group ID*" as the key to decide which __consumer_offsets partition to be used. The code is like this:
`Utils.abs(groupId.hashCode) % groupMetadataTopicPartitionCount` You can check the `partitionFor` method in GroupMetadataManager class. Hope that helps. Thank you. Luke On Fri, Sep 3, 2021 at 11:57 PM Michał Łowicki <mlowi...@gmail.com> wrote: > Hey, > > Could someone please point me to the code / doc where I can find > information what is used as key and how messages are spread across > partitions for this internal topic? > > -- > BR, > Michał Łowicki >
