查看oracle数据库里哪些语句耗时最长或者效率最低

CPU：
select *
from (select v.sql_id,
v.child_number,
v.sql_text,
v.elapsed_time,
v.cpu_time,
v.disk_reads,
rank() over(order by v.cpu_time desc) elapsed_rank
from v$sql v) a
where elapsed_rank 5 --100 0000微秒=1S
AND S.PARSING_SCHEMA_NAME = USER
AND TO_CHAR(S.LAST_LOAD_TIME, 'YYYY-MM-DD') =
TO_CHAR( SYSDATE, 'YYYY-MM-DD' )
AND S.COMMAND_TYPE IN (2 , 3, 5, 6 , 189)
ORDER BY "执行时间'S'" DESC;

/* SQL中 COMMAND_TYPE意义:
2：INSERT
3：SELECT
6：UPDATE
7：DELETE
189：MERGE
详情可通过查找V$SQLCOMMAND视图 */

V$SQLAREA 官网解释：http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3064.htm#REFRN30259
V$SQLCOMMAND 官网解释：http://docs.oracle.com/cd/E11882_01/server.112/e40402/dynviews_3066.htm#REFRN30632