Hi Neeraj, Yes, for MetadataRequest, version 0 ~ 8, the topic is ARRAY type. After version 9, it'll be COMPACT_ARRAY. It's because of this definition: "flexibleVersions": "9+". You can check KIP-482 for more information: https://cwiki.apache.org/confluence/display/KAFKA/KIP-482
Thanks. Luke On Mon, Oct 2, 2023 at 5:09 AM Neeraj Vaidya <neeraj.vai...@yahoo.co.in.invalid> wrote: > Hi All, > I've raised this on StackOverflow as well : > https://stackoverflow.com/questions/77208870/kafka-binary-protocol-array-or-compact-array > In case someone can help in answering that question. > > Regards, > Neeraj > On Sunday, 1 October, 2023 at 11:32:49 am GMT+11, Neeraj Vaidya < > neeraj.vai...@yahoo.co.in> wrote: > > Hi All, > There are 2 types of arrays specified in the Kafka protocol documentation > : ARRAY and COMPACT_ARRAY. > But in the protocol details for the different messages, it does not > explicitly specify if the array type is which one of the above. > > For example, the BNF grammar for the section for MetadataRequest API is as > below : > > Metadata Request (Version: 0) => [topics] > topics => name > name => STRING > > What is the type of [topics] ? Is it ARRAY or COMPACT_ARRAY ? > > After playing around with the protocol using some tests, I think for > Version:0 of this API request, the broker expects this to be of type ARRAY. > > But for higher versions, say v9, COMPACT_ARRAY is expected. > > I think the protocol really needs to be explicit and is lacking in this > respect. > > Regards, > Neeraj
