Hannu Krosing <hannu@tm.ee> writes:
> Are you planning to have one circular buffer per listening backend ?
No; one circular buffer, period.
Each backend would also internally buffer notifies that it hadn't yet
delivered to its client --- but since the time until delivery could vary
drastically across clients, I think that's reasonable. I'd expect
clients that are using LISTEN to avoid doing long-running transactions,
so under normal circumstances the internal buffer should not grow very
large.
regards, tom lane