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Kafka >> mail # dev >> Troubles with compressed message set

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Troubles with compressed message set
I'm working on a client and I'm running into difficulties with
compressed message sets. I am able to produce them fine, but when I go
to fetch them, things seem strange.

I am sending a message who's value is a compressed message set. The
inner message set contains a single message. Specifically what looks
weird is that the key of the top message looks corrupt. Here is a trace
of my payloads:


See the "???" down in the FetchResponse for what I mean. Also the magic
byte and attributes are wrong

The data in the Kafka log for this partition matches what I get back for
the MessageSet in the FetchResponse:


Another bit of weirdness here is how MessageSets are encoded. Everywhere
else in the API, we prefix a repeated element with a size of int32. When
encoding MessageSets, if I follow this convention, Kafka rejects the
produce request - if I exclude that int32 it works fine. I don't know if
this was intentional or not, but it is somewhat annoying and
inconsistent. When decoding MessageSets, I have to do-while instead of
iterate a known number of times.