We upgraded our Kafka clusters from 0.8.2.1 to 0.10.0.1, but most of our
consumers use older libraries that do not support the new message format.
So we set the brokers' log.message.format.version to 0.8.2 while we work on
upgrading our consumers.
In the meantime, I'm worried about a performance problem with consumers
that have upgraded and are requesting messages using the new Kafka 10
versions of those API calls.
I may be misunderstanding, but it seems logical that the performance
problem isn't just about old consumers with a new broker. I would think the
performance problem would also exist if we take new brokers, set the log
format to an old version, then have our consumers make API calls using the
Kafka 10 API calls. The broker would need to do on-the-fly conversion from
the 0.8.2 log format up to the 0.10.0 format to send to the new consumers.
This is the inverse problem of what's mentioned here:
Is this a valid problem?