I would prefer to make this a blocker for a future bugfix actually, and not 1.2.1.
The reason is that to fix this properly we might need to look again into (and possibly change) how partitioners are provided. The main problem is that the `open` method can only possibly be called once with the partitions of one topic. So, we might need the user to provide multiple partitioners, one for each of all the possible topics that will be written to. One way or another, my gut feeling is that this would need somewhat slight change to the Kafka producer APIs. And I’m not so sure of rushing API changes into releases. On April 10, 2017 at 6:46:29 AM, Gyula Fóra (gyula.f...@gmail.com) wrote: Thanks for checking this out. I would say this is definitely a blocking issue for the bugfix release, what do you think? Gyula Tzu-Li (Gordon) Tai <tzuli...@apache.org> ezt írta (időpont: 2017. ápr. 10., H, 15:39): Hi Gyula, Yes, I think the semantics of the Partitioner interface is a bit off. The `numPartitions` value ideally should be the number of partitions of the `targetTopic`. Here’s a JIRA I just filed to track the issue: https://issues.apache.org/jira/browse/FLINK-6288. Cheers, Gordon On April 10, 2017 at 1:16:18 AM, Gyula Fóra (gyula.f...@gmail.com) wrote: Hi all, We had some problems with custom partitioning for the 0.8 Kafka producer and now that I checked the code it seems there might be a problem with the logic. The producer determines the number of partitions in the open method and seems to be using that as a value passed to the custom partitioner for producing the records. This will however only work if the defaultTopicId (topic) has the same number of partitions as all other topics in the kafka cluster when producing to multiple topics. In our case the default topic had 16 and new ones have 3 as default so it gives an out of range partition error. Is my understanding correct or am I overlooking something? Thank you! Gyula