一般从v$active_session_history可以得到想要的信息，如果前面视图里已经不存在，那么可以通过
DBA_HIST_ACTIVE_SESS_HISTORY来获取需要的信息，看个小例子：
昨天某套库的CPU使用一度达到99%，作为维护人员，我们肯定要去关注，查找原因。在主机层面没有发现异常，
那么是数据库主机，问题定位在数据库上。
SELECT * FROM (
SELECT a.module
, a.sql_id
, a.session_state
, count(*)
, lpad(round(ratio_to_report(count(*)) over () * 100)||'%',10,' ') percent
FROM
dba_hist_active_sess_history a
WHERE
a.sample_time BETWEEN to_date('2012:08:01:15:00:00','YY-MM-DD:HH24:MI:SS')
AND to_date( '2012:08:01:15:40:00','YY-MM-DD:HH24:MI:SS')
GROUP BY
a.module
, a.sql_id
, a.session_state
ORDER BY
percent DESC
)
WHERE ROWNUM <= 30；
我很喜欢用如上的方式，按照某些条件来分组，来查看session对系统的影响程度，进而来分析：
MODULE SQL_ID SESSION_STATE COUNT(*) PERCENT
------------------------------------------------ ------------- ------------- ---------- -------------
PL/SQL Developer 1qbw09atztvzn ON CPU 7312 59%
PL/SQL Developer 8tg77v2fjyvus ON CPU 472 4%
JTC db-app-g17-c1b1-srv1 [email protected] 0a3db3m5h72rb ON CPU 220 2%
JTC db-app-g17-c1b1-srv2 [email protected] 0a3db3m5h72rb ON CPU 232 2%
JTC db-app-g17-c1b1-srv3 26446@pc-dbjadb17. 0a3db3m5h72rb ON CPU 197 2%
JTC db-app-g17-c1b1-srv4 26442@pc-dbjadb17. 0a3db3m5h72rb ON CPU 199 2%
PL/SQL Developer 9r57k363xqdvg ON CPU 236 2%
JTC db-app-g17-c1b2-srv1 [email protected] 0a3db3m5h72rb ON CPU 114 1%
JTC db-app-g17-c2b3-srv4 26404@pc-dbjadb17. 0a3db3m5h72rb ON CPU 67 1%
JTC db-app-g17-c2b4-srv2 [email protected] 0a3db3m5h72rb ON CPU 70 1%
JTC db-app-g17-c3b5-srv1 [email protected] 0a3db3m5h72rb ON CPU 75 1%
JTC db-app-g17-c3b5-srv3 26372@pc-dbjadb17. 0a3db3m5h72rb ON CPU 80 1%
JTC db-app-g17-c4b7-srv4 26417@pc-dbjadb17. 0a3db3m5h72rb ON CPU 63 1%
JTC db-app-g17-c4b7-srv3 26366@pc-dbjadb17. 0a3db3m5h72rb ON CPU 67 1%
JTC db-app-g17-c4b7-srv2 [email protected] 0a3db3m5h72rb ON CPU 65 1%
JTC db-app-g17-c4b7-srv1 [email protected] 0a3db3m5h72rb ON CPU 66 1%
JTC db-app-g17-c3b6-srv1 [email protected] 0a3db3m5h72rb ON CPU 62 1%
JTC db-app-g17-c3b5-srv4 26545@pc-dbjadb17. 0a3db3m5h72rb ON CPU 82 1%
JTC db-app-g17-c3b5-srv2 [email protected] 0a3db3m5h72rb ON CPU 81 1%
JTC db-app-g17-c2b4-srv3 26543@pc-dbjadb17. 0a3db3m5h72rb ON CPU 72 1%
JTC db-app-g17-c2b4-srv1 [email protected] 0a3db3m5h72rb ON CPU 62 1%
JTC db-app-g17-c2b3-srv3 26460@pc-dbjadb17. 0a3db3m5h72rb ON CPU 66 1%
JTC db-app-g17-c1b2-srv2 [email protected] 0a3db3m5h72rb ON CPU 113 1%
JTC db-app-g17-c1b2-srv4 26415@pc-dbjadb17. 0a3db3m5h72rb ON CPU 113 1%
JTC db-app-g17-c1b2-srv3 26523@pc-dbjadb17. 0a3db3m5h72rb ON CPU 119 1%
? @dbdacsb3 (TNS V1-V3) farj17af7zpq5 ON CPU 1 0%
? @dbdasso1 (TNS V1-V3) fa292z74w82s5 WAITING 1 0%
? @dbdasso1 (TNS V1-V3) ON CPU 2 0%
? @dbdasso1 (TNS V1-V3) WAITING 2 0%
? @dbjacsb1 (TNS V1-V3) 8zay3dhyxpk1s ON CPU 1 0%
30 rows selected那么我们再加入session_id来分组，哪些session在使用PLSQL DEVELOPER来执行该SQL.
MODULE SESSION_ID SQL_ID SESSION_STATE COUNT(*) PERCENT
---------------------------- ------------- ------------- ---------- -----------
PL/SQL Developer 336 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 460 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 566 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1053 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1661 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1774 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1980 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2156 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2435 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 4482 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 4400 8tg77v2fjyvus ON CPU 236 2%
PL/SQL Developer 4374 1qbw09atztvzn ON CPU 235 2%
PL/SQL Developer 4289 1qbw09atztvzn ON CPU 235 2%
PL/SQL Developer 3067 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2938 9r57k363xqdvg ON CPU 236 2%
PL/SQL Developer 2893 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2601 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2486 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 5699 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 5674 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 5570 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 5405 1qbw09atztvzn ON CPU 235 2%
PL/SQL Developer 5280 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2434 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 2057 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1871 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1709 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1505 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1437 1qbw09atztvzn ON CPU 236 2%
PL/SQL Developer 1059 8tg77v2fjyvus ON CPU 236 2%
30 rows selectedselect object_name,
owner object_owner,
status,
object_type,
created,
last_ddl_t object_type = :"SYS_B_0" and object_name not like :"SYS_B_1"
order by decode(ow owner, object_name;