分享两个SQL，这两个SQL只是基础原型，大家自己自定义条件去做一些调整。主要是在前面讲过的dba_hist_active_sess_history相关sql上总结出来的比较实用的sql。

DBA_HIST_ACTIVE_SESS_HISTORY

DBA_HIST_ACTIVE_SESS_HISTORY displays the history of the contents of the in-memory active session history of recent system activity. This view contains snapshots of V$ACTIVE_SESSION_HISTORY. See "V$ACTIVE_SESSION_HISTORY" for further interpretation details for many of these columns (except SNAP_ID, DBID, and INSTANCE_NUMBER).

查看故障时间段等待事件、问题sql id及会话访问次数

--alter session set nls_date_format='yyyy-mm-dd hh24:mi:ss'; 
select trunc(sample_time, 'mi') tm, sql_id, nvl(event,'CPU'),count(distinct session_id) cnt 
 from dba_hist_active_sess_history 
 where sample_time between to_date('2019-08-22 14:00:00') and 
 to_date('2019-08-22 14:30:00') 
 group by trunc(sample_time, 'mi'), sql_id,nvl(event,'CPU') 
 order by cnt desc; 

查看该sql相关的等待事件及对应的会话访问次数

select sql_id, nvl(event, 'CPU'), count(distinct session_id) sz 
 from dba_hist_active_sess_history a, dba_hist_snapshot b 
 where sample_time between to_date('2019-08-22 14:00:00') and 
 to_date('2019-08-22 15:00:00') 
 and sql_id = '4ksvn2rgjnhcm' 
 and a.snap_id = b.snap_id 
 and a.instance_number = b.instance_number 
 group by sql_id, nvl(event, 'CPU') 
 order by sz desc;