resmgr:cpu quantum Top Event Issues Solved

What's the problem?

Via awr report, below top event was found. How to solve Top 1 event: resmgr:cpu quantum  ?

Top 5 Timed Foreground Events

• 
  

Event	Waits	Time(s)	Avg wait (ms)	% DB time	Wait Class
resmgr:cpu quantum	150,482	109,717	729	26.75	Scheduler
DB CPU		40,945		9.98
latch: cache buffers chains	192,607	35,567	185	8.67	Concurrency
log file sync	75,662	13,579	179	3.31	Commit
db file sequential read	128,196	3,371	26	0.82	User I/O

Host CPU (CPUs: 2 Cores: Sockets: )

What's the root cause?

ResourceManager:

Subject	10g	11g
Maintenance Window	2 windows, WEEK and  WEEKEND	Each day has its own  window
Resource manager	Not enabled per  default	Default resource plan  specified

SqlTunning Advisory:

Oracle Database 11g, bydefault, the Automatic Tunning Optimizer runs regularly during the Oraclescheduler Maintenance window, as the new automated maintenance task called theSQL Tunning Advisory task.

So this is a default behavior in Oracle 11g.

SOLUTION

1].To disable the resource manager you can use the below steps.

++ set thecurrent resource manager plan to null (or another plan that is not restrictive):

alter system set resource_manager_plan='' scope=both

++ change the active windows to use the null resource manager plan (or othernonrestrictive plan) using:

execute dbms_scheduler.set_attribute('WEEKNIGHT_WINDOW','RESOURCE_PLAN',''); and
execute dbms_scheduler.set_attribute('WEEKEND_WINDOW','RESOURCE_PLAN','');

For 11g,you need to change those too:

executedbms_scheduler.set_attribute('SATURDAY_WINDOW','RESOURCE_PLAN','');
execute dbms_scheduler.set_attribute('SUNDAY_WINDOW','RESOURCE_PLAN','');
execute dbms_scheduler.set_attribute('MONDAY_WINDOW','RESOURCE_PLAN','');
execute dbms_scheduler.set_attribute('TUESDAY_WINDOW','RESOURCE_PLAN','');
execute dbms_scheduler.set_attribute('WEDNESDAY_WINDOW','RESOURCE_PLAN','');
execute dbms_scheduler.set_attribute('THURSDAY_WINDOW','RESOURCE_PLAN','');
execute dbms_scheduler.set_attribute('FRIDAY_WINDOW','RESOURCE_PLAN','');

++ Then, for each window_name (WINDOW_NAME from DBA_SCHEDULER_WINDOWS),run:

SQL> execute dbms_scheduler.set_attribute('<windowname>','RESOURCE_PLAN','');

补充如何获得awr report：

pwd

/home/oracle

export ORACLE_SID=xx

sqlplus / as sysdba

SQL> @?/rdbms/admin/awrrpt.sql

Current Instance

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

  DB Id    DB Name      Inst Num Instance

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

 165375853 WAPI2               1 wapi2

Specify the Report Type

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

Would you like an HTML report, or a plain text report?

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

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

* 165375853         1 WAPI2        wapi2        oradbhasvr00

                                               1

Using  165375853 for database Id

Using          1 for instance number

Specify the number of days of snapshots to choose from

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

Entering the number of days (n) will result in the most recent

(n) days of snapshots being listed.  Pressing <return> without

specifying a number lists all completed snapshots.

Enter value for num_days: 1

Listing the last day's Completed Snapshots

                                                       Snap

Instance     DB Name        Snap Id    Snap Started    Level

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

wapi2        WAPI2            13418 02 Aug 2013 00:00      1

                             13419 02 Aug 2013 01:00      1

                             13420 02 Aug 2013 02:00      1

Specify the Begin and End Snapshot Ids

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

Enter value for begin_snap: 13418

Begin Snapshot Id specified: 13418

Enter value for end_snap: 13420

End   Snapshot Id specified: 13420

Specify the Report Name

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

The default report file name is awrrpt_1_13418_13420.html.  To use this name,

press <return> to continue, otherwise enter an alternative.

Enter value for report_name: wapi2.html

....

然后在当前目录下获得图章诊断报告wapi2.html。