custom_metadata requires strings, so adding a bytes field may be useful to some applications, though. (This came up several years ago; you could always base64 encode but that takes time.)
On Thu, Feb 5, 2026, at 02:33, Rusty Conover wrote: > Hi Antoine, > >> Ok, perhaps we can find a generic solution using two additions: >> >> 1) a new Empty message type to avoid the overhead (and semantics) of >> empty record batches >> 2) a new application_data field in the Message table to pass arbitrary >> opaque data with any kind of message >> >> Something like: >> https://gist.github.com/pitrou/363c4509706f56743f0ca0373f20949c >> >> What do you think? > > Thanks for making the gist. It looks good to me! > > One thought I've had about the `application_data` field is that it > could be considered to be duplicative since you could accomplish the > same thing with `custom_metadata`'s KeyValue. To do that you would need > a coordinated value for the "key" field from the writer to reader. > > How can I help with this? > > Thank you, > > Rusty
