Deadlock? idle in transaction

A customer's machine hangs from time to time. All we could find so far is
that postgres seems to be in state "idle in transaction":

postgres 19317  0.0  0.3  8168  392 ?        S    Oct05   0:00 /usr/lib/postgresql/bin/postmaster -D
/var/lib/postgres/data
postgres 19983  0.0  0.8  8932 1020 ?        S    Oct05   0:01 postgres: postgres rabatt 192.168.50.222 idle in
transaction
postgres 21005  0.0  0.0  3484    4 ?        S    Oct06   0:00 /usr/lib/postgresql/bin/psql -t -q -d template1
postgres 21014  0.0  0.7  8892  952 ?        S    Oct06   0:01 postgres: postgres rabatt [local] VACUUM waiting
postgres 21833  0.0  0.4  3844  572 ?        S    Oct06   0:00 /usr/lib/postgresql/bin/pg_dump rabatt
postgres 21841  0.0  1.2  9716 1564 ?        S    Oct06   0:00 postgres: postgres rabatt [local] COPY waiting
postgres 22135  0.0  0.9  8856 1224 ?        S    Oct06   0:00 postgres: postgres rabatt 192.168.50.223 idle in
transactionwaiting
 

I'm not sure what's happening here and I have no remote access to the
machine myself. Any idea what could be the reason for this?

There may be some client processes running at the time the dump and the
vacuum commands are issued that have an open transaction doing nothing. That
is the just issued a BEGIN command. Thinking about it run some inserts at
the very same time, although that's not likely.

Any hints are appreciated. Thanks in advance.

Michael

-- 
Michael Meskes
Michael@Fam-Meskes.De
Go SF 49ers! Go Rhein Fire!
Use Debian GNU/Linux! Use PostgreSQL!