Satyanarayana Narlapuram <Satyanarayana.Narlapuram@microsoft.com> writes:
>> Why do we need to incur a protocol break to add another one?
> This is optional and is not a protocol break.
Yes, it is. We've been around on this sort of thing before and we
understand the consequences. If the option is carried in the startup
message, the client has to send it without knowing whether the server
is of new enough version to accept it. If not, the server will reject
the connection (with a scary looking message in its log) and the client
then has to retry without the option. This is not distinguishable from
what you have to do if you consider the startup message as belonging
to a new protocol version 4 instead of 3.
We have done this in the past, but it's painful, subject to bugs,
and generally is a pretty high price to pay for a marginal feature.
regards, tom lane