[erlang-questions] long sender side delays when sending to an external node

[Scott Lystig Fritchie]

Robert Raschke <rtrlists@REDACTED> wrote:

rr> I have a situation where {mbox, other_node} ! {self(), ok} is taking
rr> a very long time (8-12 seconds!). That is, the sender is actually
rr> blocked in the ! for that time.

Robby, have you seen my post to the list earlier this month about
'busy_dist_port' system events?  If the Erlang port representing the TCP
port used for inter-node communication becomes "busy", then a process
(any process) attempting to send a message through that port will be
unscheduled by the scheduler and won't be rescheduled until the busy
port is itself unblocked.

That's one way it could happen, at least.  There may be others.

-Scott