Hi Colin, Thanks for the feedback! I've changed the KIP to address your suggestions. Please find below my explanation. Here is a link to KIP 584: https://cwiki.apache.org/confluence/display/KAFKA/KIP-584%3A+Versioning+scheme+for+features .
1. '__data_version__' is the version of the finalized feature metadata (i.e. actual ZK node contents), while the '__schema_version__' is the version of the schema of the data persisted in ZK. These serve different purposes. '__data_version__' is is useful mainly to clients during reads, to differentiate between the 2 versions of eventually consistent 'finalized features' metadata (i.e. larger metadata version is more recent). '__schema_version__' provides an additional degree of flexibility, where if we decide to change the schema for '/features' node in ZK (in the future), then we can manage broker roll outs suitably (i.e. serialization/deserialization of the ZK data can be handled safely). 2. Regarding admin client needing min and max information - you are right! I've changed the KIP such that the Admin API also allows the user to read 'supported features' from a specific broker. Please look at the section "Admin API changes". 3. Regarding the use of `long` vs `Long` - it was not deliberate. I've improved the KIP to just use `long` at all places. 4. Regarding kafka.admin.FeatureCommand tool - you are right! I've updated the KIP sketching the functionality provided by this tool, with some examples. Please look at the section "Tooling support examples". Thank you! Cheers, Kowshik On Wed, Mar 25, 2020 at 11:31 PM Colin McCabe <cmcc...@apache.org> wrote: > Thanks, Kowshik, this looks good. > > In the "Schema" section, do we really need both __schema_version__ and > __data_version__? Can we just have a single version field here? > > Shouldn't the Admin(Client) function have some way to get the min and max > information that we're exposing as well? I guess we could have min, max, > and current. Unrelated: is the use of Long rather than long deliberate > here? > > It would be good to describe how the command line tool > kafka.admin.FeatureCommand will work. For example the flags that it will > take and the output that it will generate to STDOUT. > > cheers, > Colin > > > On Tue, Mar 24, 2020, at 17:08, Kowshik Prakasam wrote: > > Hi all, > > > > I've opened KIP-584 <https://issues.apache.org/jira/browse/KIP-584> > > which > > is intended to provide a versioning scheme for features. I'd like to use > > this thread to discuss the same. I'd appreciate any feedback on this. > > Here > > is a link to KIP-584: > > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-584%3A+Versioning+scheme+for+features > > . > > > > Thank you! > > > > > > Cheers, > > Kowshik > > >
