PostgreSQL 7.3.4 gets killed by SIG_KILL

I have this big table running on an old linux install (kernel 2.2.25).
I've COPYed some tcpip logs into a table created as such:

create table ipstats (time timestamp, src inet, dst inet, npackets int8,
nbytes int8);

Big:
select count(*) from ipstats;

count
----------
99173733

When i do two selects some from that table multiple times, the the
backend doing the selects is getting killed by signal 9.

The select pair look like:
select sum(nbytes) from ipstats where dst = '10.10.10.170';
select sum(nbytes) from ipstats where src = '10.10.10.170';

This is what the serverlog says:

LOG: server process (pid 20308) was terminated by signal 9
LOG: terminating any other active server processes
LOG: all server processes terminated; reinitializing shared memory and
semaphores
FATAL: The database system is starting up
LOG: database system was interrupted at 2003-12-03 23:21:49 CET
FATAL: The database system is starting up
LOG: checkpoint record is at 3/9095BC20
LOG: redo record is at 3/9095BC20; undo record is at 0/0; shutdown TRUE
LOG: next transaction id: 8716399; next oid: 141842933
LOG: database system was not properly shut down; automatic recovery in
progress
LOG: ReadRecord: record with zero length at 3/9095BC60
LOG: redo is not required
LOG: database system is ready

When i attach a gdb to the process it doesn't help, it exits immediatly
anyways.
This i believe is because SIG_KILL is "unstoppable"...

Any ideas as of what to do?

Regards
Magnus