通过案例学习调优之--Oracle ASH

应用环境：

操作系统： RedHat EL55

Oracle： Oracle 10gR2

案例场景：

SCOTT用户做事务处理，事务已经完成！

16:42:14 SYS@ prod>conn scott/tiger

Connected.

16:42:20 SCOTT@ prod>begin

16:42:23 2 for i in 1..1000000 loop

16:42:27 3 execute immediate 'insert into t1 values ('||i||')';

16:42:32 4 end loop;

16:42:36 5 end;

16:42:38 6 /

PL/SQL procedure successfully completed.

Elapsed: 00:08:35.77

16:51:14 SCOTT@ prod>commit;

Commit complete.

生成ASH报告：

16:55:43 SYS@ prod>@?/rdbms/admin/ashrpt

100

Current Instance

~~~~~~~~~~~~~~~~

DB Id DB Name Inst Num Instance

----------- ------------ -------- ------------

199802235 PROD 1 prod

Elapsed: 00:00:00.07

Specify the Report Type

~~~~~~~~~~~~~~~~~~~~~~~

Enter 'html' for an HTML report, or 'text' for plain text

Defaults to 'html'

Enter value for report_type: html

Type Specified: html

Instances in this Workload Repository schema

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

DB Id Inst Num DB Name Instance Host

------------ -------- ------------ ------------ ------------

* 199802235 1 PROD prod rh55

Defaults to current database

Using database id: 199802235

Defaults to current instance

Using instance number: 1

ASH Samples in this Workload Repository schema

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Oldest ASH sample available: 15-Aug-14 11:55:37 [ 4625 mins in the past]

Latest ASH sample available: 18-Aug-14 17:00:17 [ 1 mins in the past]

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

Enter value for begin_time: -10

Enter duration in minutes starting from begin time:

Defaults to SYSDATE - begin_time

Press Enter to analyze till current time

Enter value for duration:

Report duration specified:

Using 18-Aug-14 16:51:39 as report begin time

Using 18-Aug-14 17:01:40 as report end 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: