select only 2-level domains.

select url from d_directories_backlinks where directory_id in (select entry_id from d_directories where lang='ja') and length(split_part(replace(get_host(url),'www.',''),'.',3))=0;

network monitoring tools

http://nethogs.sourceforge.net/

Just found these great tools. the nethogs allows to measure the b/w by process id that is really helpful.