pg_stat_activity showing non-existent processes

Hello; Briefly, we've been fighting an "old idle transaction" problem
on our Pg 8.0.3 Solaris 2.9 production system for a long time. This
is due to some quirks in our app server code (to be fixed ASAP
<groan>).

Hourly we run a script that SIGTERMs all backends reported as being in
idle transaction state for 6 hours or better. Many, many runs of this
procedure during past several weeks; no problem.

Suddently, we have a condition where the pg_stat_activity view is
reporting several such backends and there is no such PID in the system
any more. These were either successfully terminated by an earlier
script run, died off abnormally or even by normal client disconnect.
(Unknown).

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?

Great big thanks!

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Jerry Sievers 305 854-3001 (home) WWW ECommerce Consultant
305 321-1144 (mobile http://www.JerrySievers.com/