查看负载：

SELECT * 
  FROM ( SELECT A.INSTANCE_NUMBER, 
               A.SNAP_ID, 
               B.BEGIN_INTERVAL_TIME + 0 BEGIN_TIME, 
               B.END_INTERVAL_TIME + 0 END_TIME, 
               ROUND(VALUE - LAG( VALUE, 1 , '0') 
                     OVER(ORDER BY A.INSTANCE_NUMBER, A.SNAP_ID)) "DB TIME" 
          FROM (SELECT B.SNAP_ID, 
                       INSTANCE_NUMBER, 
                       SUM(VALUE ) / 1000000 / 60 VALUE 
                  FROM DBA_HIST_SYS_TIME_MODEL B 
                 WHERE B.DBID = (SELECT DBID FROM V$DATABASE) 
                   AND UPPER (B.STAT_NAME) IN UPPER(('DB TIME' )) 
                 GROUP BY B.SNAP_ID, INSTANCE_NUMBER) A, 
               DBA_HIST_SNAPSHOT B 
         WHERE A.SNAP_ID = B.SNAP_ID 
           AND B.DBID = (SELECT DBID FROM V$DATABASE) 
           AND B.INSTANCE_NUMBER = A.INSTANCE_NUMBER) 
 WHERE TO_CHAR(BEGIN_TIME, 'YYYY-MM-DD') = TO_CHAR(SYSDATE , 'YYYY-MM-DD') 
 ORDER BY BEGIN_TIME; 

参考：http://blog.itpub.net/28602568/viewspace-1467897/

查看并发：

select count(*) from v$process where program='ORACLE.EXE(SHAD)';
select * from v$session;
select * from v$session where status='ACTIVE';--活动并发

参考：https://blog.csdn.net/haiross/article/details/41944493