Pgsql taking a *lot* of CPU time (unkillable).

Hello,

I'm currently running PostgreSQL 7.4.6 under NetBSD 2.0 (Release), but
with a custom kernel. I can start it, and it performs normally, i.e. I
can access my databases and such. Now I'm primarily using it with the
GNUCash PostgreSQL backend.

After I've finished using it, and leaving it to itself for a while, it
starts to consume all CPU time for, apparently, no good reason
(because it's not doing anything).

I started it thusly:
/usr/pkg/bin/postmaster -i -D /usr/pkg/pgsql/data/

And the following output appeared:

LOG:  database system was interrupted at 2005-01-14 13:52:42 CET
LOG:  checkpoint record is at 0/2329AA0
LOG:  redo record is at 0/2329AA0; undo record is at 0/0; shutdown FALSE
LOG:  next transaction ID: 46264; next OID: 142900
LOG:  database system was not properly shut down; automatic recovery in progress
LOG:  record with zero length at 0/2329AE0
LOG:  redo is not required
LOG:  database system is ready

ps auxww | grep pgsql shows:
pgsql    15786 94.8  0.3  4380   568 p2 R+    4:13PM   5:13.13
/usr/pkg/bin/postmaster -i -D /usr/pkg/pgsql/data/ (postgres)
pgsql    24309  0.0  0.0  5368     4 p2 IW+   4:13PM   0:00.01
postmaster: stats buffer process    (postgres)
pgsql    25177  0.0  0.0  4420     4 p2 IW+   4:13PM   0:00.01
postmaster: stats collector process    (postgres)
pgsql    29008  0.0  0.0     0     0 p2 ZW+        -   0:00.00 (postgres)

Top gives:
15786 pgsql     64    0  4380K  568K RUN        5:56 93.80% 93.80% postgres

Now, the program won't respond to kill, or to a ctrl+c on the command
line, I have to kill it with -9.

I've tried to run it with a higher debug level, but this does not give
any useful information, except for a sequence of (of course, while
performing query's with gnucash, a lot of query information is shown,
but after quitting it and leaving postmaster to itself only this is
shown):

DEBUG:  proc_exit(0)
DEBUG:  shmem_exit(0)
DEBUG:  exit(0)
DEBUG:  child process (PID 24738) exited with exit code 0

With varying PID's. After a while, this stops, and everything hangs as
described above. The only thing to remark is that it does not seem to
happen when running with -d 5 (but I'm not really sure).

As said, I'm running NetBSD 2.0, with my own kernel, on the i386
platform. I hope this gives someone enough information to make a guess
about the cause, although I realise the problem is quite vague.

Berteun