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AMM memory allocation with Huge amount of System Memory [message #653469]

Wed, 06 July 2016 13:55

preet_kumar
Messages: 204
Registered: March 2007

Senior Member

I am using 12c EE on x86_64 CentoOS.
Total available RAM on system is 512GB and Oracle is configured with AMM(Automatic Memory Management).There are currently 2000 applications connecting to the Database.
The number of processes configures is 8000 and the resource_limit shows the number of process does not exceed.

select * from v$resource_limit

Resource Name Current_Util Max_Util Initial_Al Limit_Val Con_Id
--------------------------------------------------------------------------
processes 2000 2300 8000 8000 0

The Tempfs(Shared Moemory) allocated is 300GB
Memory_Max_Target and Memory_Target is 300GB

If i understand correctly out of this 300GB the Oracle divides it between SGA and PGA and the current SGA usage is 200GB.
Now i notice that new application unable to connect and the Alert log shows the below message

kkjcre1p: unable to spawn jobq slave process
Process m000 died
Process J000 died

This is clearly a issue with insufficient Memory but my question is if i should allocate more memory to Oracle by increasing Memory_Max_Target or should i reduce Memory_Max_Target and free more memory for Operating System ?

The second option other than AMM is Hugepages but i hope i find a solution from experts here with AMM.

Thanks.

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Re: AMM memory allocation with Huge amount of System Memory [message #653470 is a reply to message #653469]

Wed, 06 July 2016 13:59

John Watson
Messages: 8960
Registered: January 2010
Location: Global Village

Senior Member

Quote:

kkjcre1p: unable to spawn jobq slave process
Process m000 died
Process J000 died

This is clearly a issue with insufficient Memory

No, it is not clearly that. More likely you need to raise your kernel limits, or the ulimit for the Oracle owner

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Re: AMM memory allocation with Huge amount of System Memory [message #653471 is a reply to message #653470]

Wed, 06 July 2016 14:37

preet_kumar
Messages: 204
Registered: March 2007

Senior Member

The Kernel Limit is set as per the Oracle docs

/etc/sysctl.conf

fs.file-max = 6815744
kernel.sem = 250 32000 100 128
kernel.shmmni = 4096
kernel.shmall = 1073741824
kernel.shmmax = 4398046511104

Below the limit for Oracle user
/etc/security/limits.conf
oracle soft nproc 16384
oracle hard nproc 16384

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Re: AMM memory allocation with Huge amount of System Memory [message #653475 is a reply to message #653471]

Wed, 06 July 2016 15:11

John Watson
Messages: 8960
Registered: January 2010
Location: Global Village

Senior Member

I've just had a look at your posting history, and I've noticed that you never give any feedback. Or even say "thank you" to people who try to assist.

Goodbye.

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Re: AMM memory allocation with Huge amount of System Memory [message #653476 is a reply to message #653475]

Wed, 06 July 2016 15:30

preet_kumar
Messages: 204
Registered: March 2007

Senior Member

Please note that at the end of post i have mentioned "Thanks"
Yes i will definitely appreciate if an expert provides a solution to the posting instead of providing vague solution which i can find even with simple google search and don't have to post it here.

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Re: AMM memory allocation with Huge amount of System Memory [message #653477 is a reply to message #653476]

Wed, 06 July 2016 15:38

Roachcoach
Messages: 1576
Registered: May 2010
Location: UK

Senior Member

Not using huge pages on a system that size is a recipe for disaster. I've never seen good results with AMM on a remotely busy production system.

Your process count is also far too high, most likely. Review these videos on connection pooling and management. https://blogs.oracle.com/databaseinsider/entry/oracle_s_real_world_performance

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