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