Hello all, We are in the process of upgrading all our consumers to version 0.10+. One of our pre-0.10 consumers still uses the deprecated ConsumerConnector API (I believe colloquially called the "old consumer").
We're unfortunately not able to upgrade this consumer to the new consumer API, as the consumer is baked into a larger piece of software we did not write, and they have not offered a version of it with the new consumer. They have, however, released a version using Kafka 0.10, which we have upgraded to. We also have upgraded our *brokers* to 0.10+, but per the potential performance impact <http://kafka.apache.org/0102/documentation.html#upgrade_10_performance_impact> noted in documentation have set the log.message.format.version to 0.8.2. This has worked well for us, as we've slowly been upgrading our consumers to 0.10+. My question is about using the old ConsumerConnector API with Kafka 0.10+ client and a 0.10+ broker. From my reading of the documentation, it seems the performance impact is translating the message format by the broker, and is independent of the kind (old or new) consumer. I believe both the old and new consumer both use the same fetch API, but I hadn't verified that yet. We just wanted to make sure this was correct, as to avoid any unexpected performance impacts when we finish our upgrade and change the on-broker message format to the 0.10+ one. Thanks again. Happy to answer or clarify any points of this email as needed.
