use DBI; use threads; for my $id (1..150) {async {     $db=DBI->connect(qq(dbi:Oracle:host=f$id;sid=test),qq(system/student)) or return;     print qq(login & begin to unlock $idn);     $db->do(q(begin                 for i in (select 'alter user '||username||                                  ' account unlock identified by '||username act                            from dba_users                           where username not in ('SYS','SYSTEM','SCOTT')) loop                    execute immediate i.act;                  end loop;                  execute immediate 'grant connect, resource,                                     query rewrite,                                     DEBUG CONNECT SESSION,                                     DEBUG ANY PROCEDURE                                     to public';                end;)); }}; sleep 20;