Here is what I add to the end of /usr/local/pgsql/data/postgresql.conf

Remember to HUP postmaster after doing this change.

#log_duration = on
#log_statement = all


syslog_facility = 'LOCAL0'
syslog_ident = 'postgres'
client_min_messages = error
log_min_messages = error
redirect_stderr = on
log_destination = 'stderr,syslog'

log_filename = 'postgresql-%Y-%m-%d_%H%M%S.log'
log_rotation_age = 86400
stats_command_string = on
log_line_prefix = '%m %d %p '