text: 
  
  /* wait event latency  last minute
  
     output looks like
  
     AVG_IO_MS
    ----------
         8.916
  
  */
  
  select 10*time_waited/nullif(wait_count,0) avg_io_ms -- convert centi-seconds to milliseconds
  from   v$waitclassmetric  m
         where wait_class_id= 1740759767 --  User I/O
  /
  
  