Option "notify no" also disabled query log?

[Drunkard Zhang]

Hi, all. I'm using bind-9.7.2-P3, and I want to get query log, I
pasted related configuration below:

options {
        directory "/var/";
        forward only;
        #listen-on port 53 { 10.198.2.249; 127.0.0.1; };
        forwarders {
                8.8.8.8;
        };
        pid-file "file-named.pid";
        dump-file "file-dumpfile";
        statistics-file "file-stat";
        max-cache-size 3000M;
        notify no;
        allow-query { any; };
        max-ncache-ttl 600;
        max-cache-ttl 86400;
        recursive-clients 1000000;
        tcp-clients 500000;
        interface-interval 0;
        cleaning-interval 3600;
        version "GW DNS";
        recursion yes;
};
channel query_log {
        syslog local1;
        severity info;
        print-category no;
        print-severity no;
        print-time no;
};
category queries { query_log; };

But there's no output in syslog, after change "notify no" to "notify
yes", logging via syslog works great. So I wondering is this a
intended behavior, or it's a bug. This was not mentioned in arm9.7, so
I'm asking here.