0) The patch does change major functionality, however it does not
change the documentation.
Good old proverb is "if it's not documented it does not exist".
I think we need to agree if we apply that rule or not (e.g. some SPIs
might be better "documented" in tests rather than in text form),
however here we deal with user-facing feature, so I my vote is
documentation is a must.
1) We need some sort of picture (png/svg/ascii chart/whatever) that
shows how the pieces are communicating.
Otherwise users would have no idea
1.1) which ports are required open at client and server sides
1.2) what are the security rules (authentication/authorization for the RPC)
1.3) how keep-alive is implemented (is it?), what is the connection
test query. Well, test query is certainly not a part of RPC, however
it is a must for end-users to be able to create a data source for
There is a picture here: https://raw.githubusercontent.com/julianhyde/share/master/slides/avatica-architecture.png