mysterious log output

I keep seeing the following log output around every 5 minutes:

2005-02-28 23:25:05 [8646] LOG: 00000: QUERY STATISTICS
DETAIL: ! system usage stats:
! 0.005023 elapsed 0.000000 user 0.000000 system sec
! [537.130000 user 44.860000 sys total]
! 0/0 [0/0] filesystem blocks in/out
! 0/4 [848810/1849693] page faults/reclaims, 0 [0] swaps
! 0 [0] signals rcvd, 0/0 [0/0] messages rcvd/sent
! 0/0 [0/0] voluntary/involuntary context switches
! buffer usage stats:
! Shared blocks: 0 read, 0 written, buffer hit
rate = 100.00%
! Local blocks: 0 read, 0 written, buffer hit
rate = 0.00%
! Direct blocks: 0 read, 0 written
LOCATION: ShowUsage, postgres.c:3199

The server is postgresql 7.4, running on debian linux. According to
postgres.c, it should be outputting due to GUC, however I verified that all
of the log_*_stats lines in the postgresql.conf are turned off and also
verified those GUC's are off in the show all; output... here's the relevant
bits.

log_connections | off
log_duration | off
log_error_verbosity | verbose
log_executor_stats | off
log_hostname | off
log_min_duration_statement | 5000
log_min_error_statement | info
log_min_messages | notice
log_parser_stats | off
log_pid | on
log_planner_stats | off
log_source_port | off
log_statement | off
log_statement_stats | off
log_timestamp | on

the only thing real sketchy about this is that it always seems to be on the
same pid (8646) and if I turn query logging on I see the following executed
right before this happens:

2005-03-01 00:25:08 [8646] LOG: 00000: statement: select
"_rv".cleanupEvent();
LOCATION: pg_parse_query, postgres.c:464

now according to the slony folks, there is nothing in slony that modifys the
logging output... so assuming that's true, anyone have any ideas on what
might be causing this logging?

--
Robert Treat
Build A Brighter Lamp :: Linux Apache {middleware} PostgreSQL