These views summarize wait events, grouped by event. By default, rows are sorted by descending total latency. Idle events are ignored.
          The waits_global_by_latency and
          x$waits_global_by_latency views
          have these columns:
- events- The event name. 
- total- The total number of occurrences of the event. 
- total_latency- The total wait time of timed occurrences of the event. 
- avg_latency- The average wait time per timed occurrence of the event. 
- max_latency- The maximum single wait time of timed occurrences of the event.