Backend hanging..

Hello guys, I was workin on a project today when I noticed something really
strange starting to happen...

I see backends hanging in mid-query, never to return.. I've upped the debug
level to it's max and get nothing in the logs that indicate a problem. If I
stop and restart the postmaster then the problem goes away for a few
minutes, only to return...

Some other queries seem to go through fine, it seems to be centered around
the table 'customers' as it *seems* like an update against that table will
trigger the problem..

Here is what the processes look like -- what is it "waiting" on?

61795 p2 S 0:00.38 /usr/local/pgsql/bin/postmaster -o -F -D
/usr/local/pgsql/data -i (postgres)

61812 p2 S 0:00.58 postmaster: postgres brw [local] VACUUM waiting
(postgres)
61823 p2 I 0:01.18 postmaster: postgres brw 127.0.0.1 idle in
transaction (postgres)
61836 p2 S 0:01.03 postmaster: postgres brw 127.0.0.1 UPDATE waiting
(postgres)
61860 p2 S 0:00.99 postmaster: postgres brw 127.0.0.1 idle in
transaction waiting (postgres)
61880 p2 S 0:00.99 postmaster: postgres brw 127.0.0.1 idle in
transaction waiting (postgres)

I'm running this on a Dual PII400 and a Dual PII333 one with FreeBSD 4.2 and
one with 4.3 - Both running PG 7.1.2

Any ideas? Thanks!!

-Mitch