Shared memory corrupted?

We are experiencing the following error, usually during our nightly
delete-and-vacuum cycle (when there are very few other connections to
the database):

2003-10-30 01:36:59 [25392] LOG: server process (pid 697) was
terminated by signal 14
2003-10-30 01:36:59 [25392] LOG: terminating any other active server
processes
2003-10-30 01:37:01 [1977] FATAL: The database system is in recovery mode
2003-10-30 01:37:08 [25392] LOG: all server processes terminated;
reinitializing shared memory and semaphores
2003-10-30 01:37:09 [2856] FATAL: The database system is starting up
2003-10-30 01:37:09 [2855] LOG: database system was interrupted at
2003-10-30 01:26:13 EST

The only clues we have are that the server processes interrupted by
"signal 14" *seem* to be backends connected to Apache processes (on
another server). But even that isn't certain, because of the difficulty
in tracking down which process was doing what at the time.

--
Jeff Boes vox 269.226.9550 ext 24
Database Engineer fax 269.349.9076
Nexcerpt, Inc. http://www.nexcerpt.com
...Nexcerpt... Extend your Expertise