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Memory Problem

 
karthiknarayan
Advisor

Memory Problem

I have a RP3440 machine with 16GB RAM.that runs 3 oracle databases and Tuxedo. The swap memory gets full to 100% suddenly.if i shutdown 2 oracle database it comes to 60%.But if i see all the process memory utilisation is is about 5Gb but in swapinfo it is 9GB utilised, why the memory is not freed up. please help
In Love with Life
6 REPLIES 6
Frank de Vries
Respected Contributor

Re: Memory Problem

Some basic checks:
What is your exact Oracle version ?
Version of OS (uname -a)
What are the SGA size of each DB ?

Can you give a breakdown of ipcs -m
when all db are running and
compare that with ipcs -m when only one is running.

Check the resisent memory of your process
and how they grow by doing a full listing
of top processes and rerun every 10 seconds:

UNIX95= ps -e -o pcpu -o time -o ruser -o sz -opid -o args|grep -v %CPU| sort -nr|tail -n +2|head -n 20

Also if you have access to metalink, it
could be wise to log a call on the forum,
because you could be dealing with an Oracle bug with malloc, and then you will need a patch.
Look before you leap
karthiknarayan
Advisor

Re: Memory Problem

My system swapinfo says that the Mem used is 9224476,but when i see the mem usage of all the process is ts 1234827, why the swapinfo shows extra mem utilised, if there is a mem leak how to sort it out
In Love with Life
A. Clay Stephenson
Acclaimed Contributor

Re: Memory Problem

You are reading something into the "memory" line of swapinfo that is not there. The memory line refers to pseudoswap which isn't really swap and really isn't memory usage either. It's simply a kernel bookkeeping hack that allows the machine to count 75% of physical memory as though it were swap space for process reservation calculation. This allows a machine to actually be able to run with less actual swapspace than physical memory.
If it ain't broke, I can fix that.
Frank de Vries
Respected Contributor

Re: Memory Problem

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Look before you leap
Calandrello
Trusted Contributor

Re: Memory Problem

Friend
he uses stm and he twirls one check in this memoria.
Jaime Bolanos Rojas.
Honored Contributor

Re: Memory Problem

Karthiknarayan,

Please keep in mind that applications like oracle will reserve a huge amount of memory for their use, and when that happens also a huge amount of swap will be reserved ( not used but reserved ).

The command I imagine you are using should be swapinfo -tam, if this is the case you should be concerned with the total line, than porcentange should never be close to a hundret porcent.

Also remember that for the same reason explained above, everytime that you reboot your machine, you will free up the memory, but as soon as the application starts it's going to reserved it again.

For more information on what is using your memory refer to this manual:

ftp://eh:spear9@hprc.external.hp.com/memory.htm

Regards,

Jaime.
Work hard when the need comes out.