Re: Stats Collector Oddity

Chris Browne <cbbrowne@acm.org> writes:
> We're getting a bit of an anomaly relating to pg_stat_activity...
> ...
> That PID has been dead for several days, but this connection is marked
> as being open, still, after lo many days.

This probably just means that the "backend termination" stats message
got dropped due to heavy load.  That's expected behavior in all pre-8.2
releases: the stats system was never intended to provide
guaranteed-exactly-correct status.  PG 8.2 has reimplemented the
pg_stat_activity view to make it more trustworthy.  (The other stuff is
still probabilistic, but being just event counters, message loss isn't
so obvious.)
        regards, tom lane