High CPU usage of "named" process and slow response time is observed

Issue

• named process consumes a lot of CPU and slow response time is observed

  $ ps -auxwwwm | (head -1; grep -w ^named)
  USER         PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  named      49484  505  3.9 3017968 643136 ?      -    01:23 2706:17 /usr/sbin/named -u named -c /etc/named.conf
  named          -  0.0    -      -     - -        Ssl  01:23   0:00 -
  named          - 14.8    -      -     - -        Ssl  01:23  79:32 -
  named          - 14.8    -      -     - -        Ssl  01:23  79:44 -
  named          - 14.8    -      -     - -        Ssl  01:23  79:42 -
  named          - 14.8    -      -     - -        Ssl  01:23  79:47 -
   :
  

  In the example above, the process consumes 5 CPUs.