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##                    How to implement Oracle Instance Caging 
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Instance Caging allows to dynamically limit the amount of CPUs used by each database instance. 
This option is specifically thought for shared environments where the database administrator
has to guarantee resources to all the instances running on the same hardware.



-- Enable Resource Manager:

ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = 'REAL_TIME_PLAN';

--or

ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = 'FORCE:REAL_TIME_PLAN';

FORCE option prevents that the scheduler window activates a different plan during the job execution.

(for more info about Resource Manager visit ResourceManager)



-- Enable Instance Caging:

ALTER SYSTEM SET CPU_COUNT=4 SCOPE=BOTH SID='*';


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##                    Instance Caging Test
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Hardware SUN 8 Cores 64 Threads
One test database capped to 16 CPU - 25% of total hardware capacity.


ALTER SYSTEM SET RESOURCE_MANAGER_PLAN = 'default_plan';
ALTER SYSTEM SET cpu_count=16 scope=both sid='*';

The load generator opens 70 sessions producing intencive CPU activity, which as shown by the reports below
do not exceed the 25% od the total server capacity (%Usr column).


  
   Core Utilization for Integer pipeline
Core,Int-pipe  %Usr     %Sys     %Usr+Sys
-------------         -----     -----    --------
     0,0              21.92      3.99     25.91
     0,1              24.58      2.08     26.66
     1,0              23.16      2.27     25.43
     1,1              24.06      2.64     26.71
     2,0              22.73      3.03     25.76
     2,1              23.47      3.02     26.49
     3,0              23.56      2.86     26.42
     3,1              24.71      2.87     27.58
     4,0              23.53      2.07     25.60
     4,1             24.87      2.92     26.79
     5,0             24.98      2.87     27.85
     5,1             24.76      3.81     28.57
     6,0             23.53      4.11     27.64
     6,1             23.99      3.14     27.13
     7,0             24.72      3.55     28.26
     7,1             22.62      3.59     26.21
-------------        -----        -----    ------
    Avg           22.36      3.05     25.41


If on the Wait Events is present "resmgr:cpu quantum", it means that Instance Caging throttled the amount of CPUs available to the system.

INST_ID  SID      SQL_ADDR                       EVENT           WAIT_CLASS              STATE                 WAIT_MICRO    REMAING   TOT_TIME  LAST_WAIT
-------       ------      ----------------               ------------------------------ ---------------                     ------------------                     ----------            ----------          ----------        ----------
      1       676      000000047ECC5BD0   resmgr:cpu quantum     Scheduler       WAITED KNOWN TIME       11599                                11599      43834
      2       624      000000047D7D38D0    resmgr:cpu quantum     Scheduler       WAITED KNOWN TIME       11599                                11599      43834
      2       395      000000047BCA97A8   resmgr:cpu quantum     Scheduler       WAITING                            11669                     -1         11668          0
      1       300      000000047C8D6B38    resmgr:cpu quantum     Scheduler       WAITED KNOWN TIME       11677                                 11677        589
      2       317      00                                 resmgr:cpu quantum     Scheduler       WAITED KNOWN TIME       11677                                  11677        589
      1       649      000000047ECC5BD0   resmgr:cpu quantum     Scheduler       WAITING                            14445                     -1          14444          0
      2       676      000000047D7D38D0    resmgr:cpu quantum     Scheduler       WAITING                            14445                     -1          14444          0
      1       148      000000047C8D6B38    resmgr:cpu quantum     Scheduler       WAITING                             14827                     -1          14826          0
      2     1413      000000047D7D36E0    resmgr:cpu quantum      Scheduler       WAITED KNOWN TIME       18824                                  18824      98023
      1      148      000000047ECC4010     resmgr:cpu quantum      Scheduler       WAITED KNOWN TIME       18824                                  18824      98023
      1       149     000000047C8D6B38    resmgr:cpu quantum       Scheduler       WAITING                             19122                     -1          19121          0
      1        69      000000047C8D6B38    resmgr:cpu quantum       Scheduler       WAITING                             19177                     -1          19176          0
      2        51      000000047BCA97A8   resmgr:cpu quantum        Scheduler       WAITING                             19177                     -1           19176          0
      2     1106     000000047BCA97A8   PX Deq: Signal ACK RSG    Other        WAITING                              112660                  7340         120000          0





 

 
   
 
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