session lock feedback

hi everyone
i want to give feedback when query takes long and user session locked, i mean like "you should wait until query ends"  i have tried but no results for me 
i have get_lock function in those pages

• Session_database_driver.php 
  
• Session_memcached_driver.php
  
• session_redis_driver.php
  
• Session_driver.php
  

i have tried which function works when session locks but i dont find.
i guess "SELECT GET_LOCK('".$arg."', 300) AS ci_session_lock")->row()->ci_session_lock" is locked my session but i did comment that line nothing is affected
thanks for suggestions