Re: pg_stat_activity showing non-existent processes

>>> On Sat, Mar 25, 2006 at 8:40 pm, in message
<22874(dot)1143340808(at)sss(dot)pgh(dot)pa(dot)us>,
Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Jerry Sievers <jerry(at)jerrysievers(dot)com> writes:
>> At any rate; I'm wondering what possible causes might be
responsible
>> for pg_stat_activity's underlying functions to lose track of the
valid
>> process list?
>
> It sounds like the stats collector missed a few "backend quit"
> messages. This isn't real surprising: the stats messaging mechanism
is
> intentionally designed to drop messages under severe load, rather
than
> slow down backends.

Is there any way to tweak this in favor of more accurate information,
even if has a performance cost? We're finding that during normal
operations we're not seeing most connections added to the
pg_stat_activity table. We would like to be able to count on accurate
information there. We've been considering adding functions to get at
the underlying structures to be able to retrieve it, but it would make a
lot of sense (for us, anyway) to make this table accurate instead. What
would be involved in that? Would it improve the accuracy of the other
statistics, as well? Would anyone else be interested in something like
this (probably controlled by a configuration option), or are we unique
in this regard?

-Kevin