Bind log stopped with log rotation configuration on ubuntu hardy

Today I found the bind query log had stopped for over 24 hours.

-rw-r--r-- 1 bind bind 20971580 2009-08-17 12:58 query.log

When looking for the reason, the logging configuration was checked but
everything is ok there.

logging {
channel query.log {
file "/var/log/named/query.log" versions 30 size 20m;
severity debug 3;
print-time yes;
print-category yes;
};
category queries { query.log; };
}

Finally it is found that here is something wrong with the apparmor
configuration, which have to be fixed.

Just add the following
/var/log/named/ rw,
to
/etc/apparmor.d/usr.sbin.named
and reload bind with
rdnc reload