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怎样利用ash监控会话

2017-06-13 14:28 288 查看
ash是很有效的监控工具之中的一个。1秒抓一次
select max(sample_time)over(),min(sample_time)over() from dba_hist_active_sess_history;  --8天
select max(sample_time)over(),min(sample_time)over() from v$active_session_history;  --当天

首先先了解几个视图:
V$ACTIVE_SESSION_HISTORY: 是ASH的核心。用以记录活动SESSION的历史等待信息。每秒採样一次。这部分内容记录在内存中,期望值是记录一个小时的内容。
WRH#_ACTIVE_SESSION_HISTORY : 是V$ACTIVE_SESSION_HISTORY在AWR的存储地。
V$ACTIVE_SESSION_HISTORY: 中的信息会被定期(每小时一次)的刷新到负载库中,并缺省保留一个星期用于分析。
DBA_HIST_ACTIVE_SESS_HISTORY: 视图是WRH#_ACTIVE_SESSION_HISTORY视图和其它几个视图的联合展现,通常通过这个视图进行历史数据的訪问。

------------------------------------
--V$ACTIVE_SESSION_HISTORY的监控:--
------------------------------------

------------session:1-----------------

SQL> @big

SID
----------
131

Elapsed: 00:00:00.00
drop table big
*
ERROR at line 1:
ORA-00942: table or view does not exist

Elapsed: 00:00:00.03
Elapsed: 00:00:00.31
Elapsed: 00:00:00.34
Elapsed: 00:00:00.29
Elapsed: 00:00:00.73
Elapsed: 00:00:01.75
Elapsed: 00:00:10.59
Elapsed: 00:00:24.62
Elapsed: 00:00:00.01

BIG_M
----------
522
Elapsed: 00:00:00.36

COUNT(*)
----------
4650368
Elapsed: 00:00:26.70

------------session:2-----------------

SQL> @getash_sid
Enter value for sid: 131

SESSION_ID NAME                                                             P_NAME          P_VALUE      SQL_ID    WAIT_TIME CURRENT_OBJ# CURRENT_FILE# CURRENT_BLOCK#
---------- ---------------------------------------------------------------- --------------- --------------- ------------- ---------- ------------ ------------- ---------
131 db file sequential read                                          file#           1            d2wbn28rdk8z4     0          547             1           3604
block#          53206
blocks          1

131 db file sequential read                                          file#           1            d2wbn28rdk8z4     0           -1             0              0
block#          3009
blocks          1

131 db file scattered read                                           file#           4            03b71c07nsc1a     0          134             1           1064
block#          4845
blocks          8

131 log buffer space                                                                 0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch completion                                                       0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           6046
0
0

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4           4995
block#          4995
blocks          5

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           7170
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4           7170
0
0

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4           8578
block#          8578
blocks          126

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          12802
block#          12802
blocks          126

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4          12930
0
0

131 db file sequential read                                          file#           1            aq32z6wjx1s4h     0        65921           201           3585
block#          2854
blocks          1

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          14084
block#          14084
blocks          124

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          18436
block#          18436
blocks          128

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          19972
block#          19972
blocks          128

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          21252
block#          21252
blocks          124

131 db file parallel read                                            files           1            aq32z6wjx1s4h     0        76851             4          23424
blocks          29
requests        29

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4          24320
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4          24320
0
0

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          25856
block#          25856
blocks          128

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          27652
block#          27652
blocks          124

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          29312
block#          29312
blocks          32

131 Disk file operations I/O                                         FileOperation   2            aq32z6wjx1s4h     0        76851             4          29952
fileno          0
filetype        2

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          30724
block#          30724
blocks          124

131 db file scattered read                                           file#           4            aq32z6wjx1s4h     0        76851             4          34530
block#          34530
blocks          14

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4          35716
0
0

131 log file switch (checkpoint incomplete)                                          0            aq32z6wjx1s4h     0        76851             4          35716
0
0

131 Disk file operations I/O                                         FileOperation   5            aq32z6wjx1s4h     0        76851             4          37632
fileno          0
filetype        2

131 db file sequential read                                          file#           4            fqcxb1n33642x     0            9             1          86832
block#          4999
blocks          1

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          10344
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          17409
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          22083
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          28549
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          34733
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          39217
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          45114
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          48836
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0            9             1          86832
block#          52391
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4           5196
block#          5196
blocks          6

131 db file sequential read                                          file#           4            fqcxb1n33642x     0        76851             4           8261
block#          8261
blocks          1

131 db file sequential read                                          file#           4            fqcxb1n33642x     0        76851             4          11318
block#          11318
blocks          1

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          14489
block#          14489
blocks          56

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          17935
block#          17935
blocks          50

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          21195
block#          21195
blocks          20

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          25170
block#          25170
blocks          2

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          28453
block#          28453
blocks          34

131 db file sequential read                                          file#           4            fqcxb1n33642x     0        76851             4          33067
block#          33067
blocks          1

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          36991
block#          36991
blocks          13

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          41616
block#          41616
blocks          21

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          44055
block#          44055
blocks          8

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4           2723
block#          2723
blocks          44

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          50056
block#          50056
blocks          9

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          53658
block#          53658
blocks          102

131 db file scattered read                                           file#           4            fqcxb1n33642x     0        76851             4          56580
block#          56580
blocks          128

131 db file sequential read                                          file#           4            fqcxb1n33642x     0        76851             4          60256
block#          60256
blocks          1

64 rows selected.

Elapsed: 00:00:00.40
SQL> @getsql_sqlid
Enter 1 for curr sql, 2 for hist sql,default 1:

Enter value for sqlid: fqcxb1n33642x

SQL_FULLTEXT
---------------------------------------------------------------------------------------------
select count(*) from big
Elapsed: 00:00:00.00
Elapsed: 00:00:00.00
SQL> @getobj_id
Enter value for dblink:
Enter value for obj_id: 76851

OWNER                OBJECT_NAME                    OBJECT_TYPE         CREATED             STATUS
-------------------- ------------------------------ ------------------- ------------------- -------
SCOTT                BIG                            TABLE               2014-11-20 15:56:23 VALID

1 row selected.

Elapsed: 00:00:00.01
SQL> @getobj_fb
Enter value for file_id: 4
Enter value for block_id: 60256

OWNER           SEGMENT_NAME         SEGMENT_TY
--------------- -------------------- ----------
SCOTT           BIG                  TABLE

1 row selected.

Elapsed: 00:00:00.37

--------------------------@脚本--------------------

--@big

@sid
set feedback off
drop table big;
create table big as select * from dba_objects;
insert into big select * from big;
/
/
/
/
/
commit;
select SUM(bytes) / 1024 / 1024  big_M  from dba_segments where segment_name = 'BIG';
select count(*) from big;
set feedback on

--@getash_sid
col p_name for a15
col p_value for a15
select SESSION_ID,
NAME,
P1TEXT||chr(10)||P2TEXT||chr(10)||P3TEXT p_name,
p1||chr(10)||p2||chr(10)||p3 p_value,
sql_id,
WAIT_TIME,
CURRENT_OBJ#,
CURRENT_FILE#,
CURRENT_BLOCK#
from v$active_session_history ash, v$event_name enm
where ash.event# = enm.event#
and SESSION_ID = &sid
order by sample_time;

----------------------------------------
--DBA_HIST_ACTIVE_SESS_HISTORY的监控:--
----------------------------------------

--查当前时间
select to_char(sysdate,'yyyy-mm-dd hh24:mi:ss') from dual;

--依据时间找到snap_id(8天内,1小时前),由于基表很大,利用snap_id的索引才干高速查询
select distinct snap_id from dba_hist_snapshot b where to_date('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss') between b.begin_interval_time and b.end_interval_time;

--top instance
select /*+parallel(a,8)*/instance_number,count(*) from dba_hist_active_sess_history a where a.snap_id=67421 group by instance_number;

--top event
select /*+parallel(a,8)*/event,count(*) from dba_hist_active_sess_history a
where a.snap_id=67421
and instance_number=2
and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss')
and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss')
group by event
order by count(*) desc;

--top user
select /*+parallel(a,8)*/user_id,(select username from dba_users b where b.user_id=a.user_id) username,count(*) from dba_hist_active_sess_history a
where a.snap_id=67421
and instance_number=2
and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss')
and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss')
group by user_id
order by count(*) desc;

--top sql
select /*+parallel(a,8)*/sql_id,count(*) from dba_hist_active_sess_history a
where a.snap_id=67421
and instance_number=2
and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss')
and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss')
group by sql_id
order by count(*) desc;

--   select SQL_TEXT from dba_hist_sqltext where sql_id='49p4hfj6azw19';

--top program
select /*+parallel(a,8)*/program,count(*) from dba_hist_active_sess_history a
where a.snap_id=67421
and instance_number=2
and sample_time>=to_timestamp('2014-11-20 14:07:12','yyyy-mm-dd hh24:mi:ss')
and sample_time<=to_timestamp('2014-11-20 14:08:12','yyyy-mm-dd hh24:mi:ss')
group by program
order by count(*) desc;
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