Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp> writes:
> BTW I have a question about this example.
> Session 2 deletes no row because *session 1* already
> deleted the rows but the session_del rule seems to
> be invoked. Is it a right behavior ?
Certainly the rule should be invoked --- whether it finds any rows
cannot be determined until it's invoked, anyhow. Remember a rule
is not a trigger, it is a transform applied to the query before
we begin execution.
regards, tom lane