Sudden stop of postmaster - Looking for help

Hello,

My RH 7.3 PGSQL 7.2 suddenly died last night and left me with no idea
of what happened. I am looking for a logfile and not finding one with
anything interesting in it. Any clues as to where the postmaster
might've dumped a record of what happened?

Here's the message returned from pg_ctl with the -s option which
helped me to re-start the stubborn postmaster. Could someone help me
deduce whether this is a serious issue or not please.

TIA!!!

bash-2.05a$ pg_ctl start -D /var/lib/pgsql/data -s
pg_ctl: Another postmaster may be running. Trying to start postmaster
anyway.
Found a pre-existing shared memory block (ID 196608) still in use.
If you're sure there are no old backends still running,
remove the shared memory block with ipcrm(1), or just
delete "/var/lib/pgsql/data/postmaster.pid".
pg_ctl: cannot start postmaster
Examine the log output.

bash-2.05a$ rm /var/lib/pgsql/data/postmaster.pid
bash-2.05a$ pg_ctl start -D /var/lib/pgsql/data -s
bash-2.05a$ DEBUG: database system was interrupted at 2003-03-17
21:39:38 UTC
DEBUG: checkpoint record is at 0/DC2A414
DEBUG: redo record is at 0/DC2A414; undo record is at 0/0; shutdown
FALSE
DEBUG: next transaction id: 1081353; next oid: 37710
DEBUG: database system was not properly shut down; automatic recovery
in progress
DEBUG: ReadRecord: record with zero length at 0/DC2A454
DEBUG: redo is not required
DEBUG: database system is ready

DAVE