postgres deadlocks

My postgres deadlocked again today. Logs indicated that before the
nightly vacuum -z everything was fine, but after it was locked. The
postgres.log contained the end of the vacuum which appeared to be
consistant with the other vacuums in the log. A ps showed no vacuuming
processes, but it did show one 'idle in transaction'. This problem last
happened in Februrary when I was using 7.0.3.

select version();
version
---------------------------------------------------------------------
PostgreSQL 7.1.2 on i686-pc-linux-gnu, compiled by GCC egcs-2.91.66
(1 row)

[root(at)p1 /var/log] ps ax | grep postgres
16973 ? S 0:36 postgres: user2 owl 127.0.0.1 idle
17105 ? S 0:01 postgres: user2 owl 127.0.0.1 idle
17122 ? S 1:51 postgres: user2 owl 127.0.0.1 idle
17302 ? S 1:19 postgres: user2 owl 127.0.0.1 UPDATE waiting
17453 ? S 0:32 postgres: user2 owl 127.0.0.1 idle
18202 ? S 0:03 postgres: user2 owl 127.0.0.1 idle
18351 ? S 0:12 postgres: user2 owl 127.0.0.1 idle in
transaction
18352 ? S 0:00 postgres: user2 owl 127.0.0.1 idle
7137 ? S 0:00 postgres: user2 owl 127.0.0.1 idle

--
Joseph Shraibman
jks(at)selectacast(dot)net
Increase signal to noise ratio. http://www.targabot.com