fatal error in database

Howdy:

Running PostgreSQL 7.2.1 on RedHat Linux 7.2.

I'm having a problem trying to identify some of the causes
for the following errors:

[snip]
test=> select count (*) from t_testob;
FATAL 2: open of /raid/pgsql/data/pg_clog/0373 failed: No such file or
directory
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
The connection to the server was lost. Attempting reset: NOTICE: Message
from PostgreSQL backend:
The Postmaster has informed me that some other backend
died abnormally and possibly corrupted shared memory.
I have rolled back the current transaction and am
going to terminate your database system connection and exit.
Please reconnect to the database system and repeat your query.
Failed.
!>

[/snip]

I have a log file that captures some errors (my debug level is 2)
and it says this:

[snip]
Nov 27 12:51:58 hmp2 postgres[9715]: [4] FATAL 2: open of
/raid/pgsql/data/pg_clog/0373 f
ailed: No such file or directory
Nov 27 12:51:58 hmp2 postgres[9715]: [4] FATAL 2: open of
/raid/pgsql/data/pg_clog/0373 f
ailed: No such file or directory
Nov 27 12:51:58 hmp2 postgres[9484]: [4] DEBUG: server process (pid 9715)
exited with exi
t code 2
Nov 27 12:51:58 hmp2 postgres[9484]: [5] DEBUG: terminating any other
active server proce
sses
Nov 27 12:51:59 hmp2 postgres[9716]: [4-1] NOTICE: Message from PostgreSQL
backend:
Nov 27 12:51:59 hmp2 postgres[9716]: [4-2] ^IThe Postmaster has informed me
that some othe
r backend
Nov 27 12:51:59 hmp2 postgres[9716]: [4-3] ^Idied abnormally and possibly
corrupted shared
memory.
Nov 27 12:51:59 hmp2 postgres[9716]: [4-4] ^II have rolled back the current
transaction an
d am
Nov 27 12:51:59 hmp2 postgres[9716]: [4-5] ^Igoing to terminate your
database system conne
ction and exit.
Nov 27 12:51:59 hmp2 postgres[9716]: [4-6] ^IPlease reconnect to the
database system and r
epeat your query.
Nov 27 12:51:59 hmp2 postgres[9484]: [6] DEBUG: all server processes
terminated; reinitia
lizing shared memory and semaphores
Nov 27 12:51:59 hmp2 postgres[9717]: [7] DEBUG: database system was
interrupted at 2002-1
1-27 12:39:30 EST
Nov 27 12:51:59 hmp2 postgres[9717]: [8] DEBUG: checkpoint record is at
8/21BFC274
Nov 27 12:51:59 hmp2 postgres[9717]: [9] DEBUG: redo record is at
8/21BFC274; undo record
is at 0/0; shutdown FALSE
Nov 27 12:51:59 hmp2 postgres[9717]: [10] DEBUG: next transaction id:
15999894; next oid:
138653530
Nov 27 12:51:59 hmp2 postgres[9717]: [11] DEBUG: database system was not
properly shut do
wn; automatic recovery in progress
Nov 27 12:51:59 hmp2 postgres[9717]: [12] DEBUG: ReadRecord: record with
zero length at 8
/21BFC2B4
Nov 27 12:51:59 hmp2 postgres[9717]: [13] DEBUG: redo is not required
Nov 27 12:52:01 hmp2 postgres[9717]: [14] DEBUG: database system is ready

[/snip]

When it says, 'corrupt shared memory', I'm *hoping* this has nothing to do
with 'physical memory'.

Can someone tell me how I can stress test PostgreSQL so that I
can find out what the error is really referring to?

Thanks!

-X