ASH汇报的产生-学习小结
ASH报告的产生
You can examine the current Active Session Hist ory (ASH) data in the V$ACTIVE_SESSION_HISTORY view
and historical data in the DBA_HIST_ACTIVE_SESS_HISTORY view
<1>V$ACTIVE_SESSION_HISTORY
one sample every 1 seconds
<2>DBA_HIST_ACTIVE_SESS_HISTORY
one sample every 10 seconds
查看当前活跃回话的ash data 信息
select * from V$ACTIVE_SESSION_HISTORY；
SAMPLE_ID SAMPLE_TIME
---------- ------------------------------
430857 18-3月 -13 08.20.06.998 下午
430782 18-3月 -13 08.18.51.965 下午
430781 18-3月 -13 08.18.50.965 下午
430780 18-3月 -13 08.18.49.969 下午
430779 18-3月 -13 08.18.48.965 下午
430778 18-3月 -13 08.18.47.965 下午
430737 18-3月 -13 08.18.06.966 下午
430734 18-3月 -13 08.18.03.967 下午
430731 18-3月 -13 08.18.00.967 下午
430728 18-3月 -13 08.17.57.967 下午
430722 18-3月 -13 08.17.51.967 下午
。。。。。
查看ash data的历史信息：
SQL> select * from DBA_HIST_ACTIVE_SESS_HISTORY;
SNAP_ID DBID INSTANCE_NUMBER SAMPLE_ID SAMPLE_TIME
---------- ---------- --------------- ---------- -------------------------------
154 2546074315 1 407670 16-3月 -13 07.55.56.716 下午
161 2546074315 1 422430 18-3月 -13 06.00.41.425 下午
161 2546074315 1 425330 18-3月 -13 06.49.01.498 下午
159 2546074315 1 419670 18-3月 -13 05.14.38.109 下午
159 2546074315 1 419670 18-3月 -13 05.14.38.109 下午
159 2546074315 1 419670 18-3月 -13 05.14.38.109 下午
159 2546074315 1 419670 18-3月 -13 05.14.38.109 下午
159 2546074315 1 419670 18-3月 -13 05.14.38.109 下午
159 2546074315 1 419680 18-3月 -13 05.14.48.109 下午
159 2546074315 1 419970 18-3月 -13 05.19.38.153 下午
158 2546074315 1 416070 17-3月 -13 03.00.24.075 下午
。。。。。。。
ash内存的使用：
The memory for the ASH come s from the System Global Area (SGA), and it is fixed for
the lifetime of the instance. It represents 2 MB of memory per CPU. The ASH cannot exceed a
maximum bound of five percent of the shared pool size , or five percent of the SGA_TARGET.
在sqlplus 下使用脚本产生ash 报告：
脚本默认位置： $ORACLE_HOME/rdbms/admin/ashrpt.sql
以下为windows server 2003下测试：
SQL> @?/rdbms/admin/ashrpt.sql -------------- @表示执行sql脚本 ；? 表示$oracle_home
Current Instance
~~~~~~~~~~~~~~~~
DB Id DB Name Inst Num Instance
----------- ------------ -------- ------------
2546074315 MAX 1 max
Specify the Report Type
~~~~~~~~~~~~~~~~~~~~~~~
Enter 'html' for an HTML report, or 'text' for plain text
Defaults to 'html'
输入 report_type 的值: html
Type Specified: html
Instances in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DB Id Inst Num DB Name Instance Host
------------ -------- ------------ ------------ ------------
* 2546074315 1 MAX max MAX
Defaults to current database
Using database id: 2546074315
Defaults to current instance
Using instance number: 1
ASH Samples in this Workload Repository schema
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
行将被截断
行将被截断
行将被截断
行将被截断
Oldest ASH sample available: 13-3月 -13 16:39:48 [ 7429 mins in the pa
Specify the timeframe to generate the ASH report
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Enter begin time for report:
-- Valid input formats:
-- To specify absolute begin time:
-- [MM/DD[/YY]] HH24:MI[:SS]
-- Examples: 02/23/03 14:30:15
-- 02/23 14:30:15
-- 14:30:15
-- 14:30
-- To specify relative begin time: (start with '-' sign)
-- -[HH24:]MI
-- Examples: -1:15 (SYSDATE - 1 Hr 15 Mins)
-- -25 (SYSDATE - 25 Mins)
Defaults to -15 mins
输入 begin_time 的值:
Report begin time specified:
Enter duration in minutes starting from begin time:
Defaults to SYSDATE - begin_time
Press Enter to analyze till current time
输入 duration 的值:
Report duration specified:
行将被截断
Using 18-3月 -13 20:17:24 as report begin time
Specify Slot Width (using ashrpti.sql) for 'Activity Over Time' section
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Explanation:
-- In the 'Activity Over Time' section of the ASH report,
-- the analysis period is divided into smaller slots
-- and top wait events are reported in each of those slots.
-- Default:
-- The analysis period will be automatically split upto 10 slots
-- complying to a minimum slot width of
-- 1 minute, if the source is V$ACTIVE_SESSION_HISTORY or
-- 5 minutes, if the source is DBA_HIST_ACTIVE_SESS_HISTORY.
Specify Slot Width in seconds to use in the 'Activity Over Time' section:
Defaults to a value as explained above:
Slot Width specified:
Specify Report Targets (using ashrpti.sql) to generate the ASH report
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-- Explanation:
-- ASH Report can accept "Report Targets",
-- like a particular SQL statement, or a particular SESSION,
-- to generate the report on. If one or more report targets are
-- specified, then the data used to generate the report will only be
-- the ASH samples that pertain to ALL the specified report targets.
-- Default:
-- If none of the report targets are specified,
-- then the target defaults to all activity in the database instance.
Specify SESSION_ID (eg: from V$SESSION.SID) report target:
Defaults to NULL:
SESSION report target specified:
Specify SQL_ID (eg: from V$SQL.SQL_ID) report target:
Defaults to NULL: (% and _ wildcards allowed)
SQL report target specified:
Specify WATI_CLASS name (eg: from V$EVENT_NAME.WAIT_CLASS) report target:
[Enter 'CPU' to investigate CPU usage]
Defaults to NULL: (% and _ wildcards allowed)
WAIT_CLASS report target specified:
Specify SERVICE_HASH (eg: from V$ACTIVE_SERVICES.NAME_HASH) report target:
Defaults to NULL:
SERVICE report target specified:
Specify MODULE name (eg: from V$SESSION.MODULE) report target:
Defaults to NULL: (% and _ wildcards allowed)
MODULE report target specified:
Specify ACTION name (eg: from V$SESSION.ACTION) report target:
Defaults to NULL: (% and _ wildcards allowed)
ACTION report target specified:
Specify CLIENT_ID (eg: from V$SESSION.CLIENT_IDENTIFIER) report target:
Defaults to NULL: (% and _ wildcards allowed)
CLIENT_ID report target specified:
Specify the Report Name
~~~~~~~~~~~~~~~~~~~~~~~
The default report file name is ashrpt_1_0318_2032.html. To use this name,
press <return> to continue, otherwise enter an alternative.
输入 report_name 的值: 《 需要填入ash报告的文件名可添加目录 eg：d:/ashrpt_1_0318_2032.html 或者 /tmp/ashrpt_1_0318_2032.html》
Returns most active SQL in the past minute
查找最近活跃度最高的sql语句：
SELECT sql_id, count(*),
round(count(*)/sum(count(*)) over (), 2) pctload
FROM v$active_session_history
WHERE sample_time > sysdate -1/24/60 and
session_type <> 'BACKGROUND'
GROUP BY sql_id
ORDER BY count(*) desc;
当有多个数据库是可以使用以下脚本：
SQL> define dbid = '';
SQL> define inst_num = '';
SQL> define report_type = 'html';
SQL> define begin_time = '09:00';
SQL> define duration = 480;
SQL> define report_name = '/tmp/sql_ashrpt.txt';
SQL> define slot_width = '';
SQL> define target_session_id = '';
SQL> define target_sql_id = 'abcdefghij123';
SQL> define target_wait_class = '';
SQL> define target_service_hash = '';
SQL> define target_module_name = '';
SQL> define target_action_name = '';
SQL> define target_client_id = '';
SQL> @?/rdbms/admin/ashrpti