[jira] [Created] (KAFKA-12286) Consider storage/cpu tradeoff in metadata record framing schema

["Jason Gustafson (Jira)" <ji...@apache.org>]

Jason Gustafson created KAFKA-12286:
---------------------------------------

             Summary: Consider storage/cpu tradeoff in metadata record framing schema
                 Key: KAFKA-12286
                 URL: https://issues.apache.org/jira/browse/KAFKA-12286
             Project: Kafka
          Issue Type: Improvement
            Reporter: Jason Gustafson


KIP-631 calls for unsigned varints in order to represent the api key and version. We are also adding a frame version, which will be unsigned varint. The use of the varint means we can save a byte from each of these fields compared to an int16. The downside is that it is that the serialization is a little more expensive. For varints, we typically require one call to compute the size of the field and a separate call to actually write it. If this becomes an issue, there are a couple options:

1. We can use the int16 and pay the extra 3 bytes.
2. We can let the generated classes compute the encoded api key and version as a byte and fail if we ever exceed the range of varint that can fit in a single byte. This would let us replace `writeUnsignedVarint` with `writeByte`.

The second option seems reasonable to me. I think it's extremely unlikely we'll ever need more than a byte for either the api key or the version. At least it should be years before that happens and we will have options to deal with it if it does.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)