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Home -> Community -> Mailing Lists -> Oracle-L -> Re: private memory used by oracle process in AIX ??
Hi Prem,
Are you aware regarding UNIX virtual memory mechanisms?
I am asking because from vmstat, ps, top and others OS tools, which
aggregate memory utilization information (RSS, VSZ etc) we can’t see for
sure how many Memory utilizing each process.
This is because VSZ figure include not just privet memory areas, but also
shared memory (like SGA) and TEXT (code). RSS represent VSZ process memory
which in RAM at the moment (other part swapped).
The way how different OS-es show RSS, VSZ figures differs from one OS to
other, but principles preserve.
.
Some OS-es have tools which allows to see in details all memory areas. For
example:
Solaris - /usr/proc/bin/pmap
Linux - cat /proc/<pid>/maps
Unfortunately I unaware of such tool on AIX. PS If you will find one, please share this information.
I you are interesting to investigate dipper, how UNIX manage and reflect information about memory utilization, then I would recommend to read “The SolarisMemorySystem Sizing,ToolsandArchitecture” from Sun. Document about Solaris, but main concepts are the same for UNIXes.
Any body, please correct me, in case I am wrong,
Best regards,
Jurijs
9268222
PS One way how you can try to calculate the MEM utilizations by each Oracle process (with known approximately), is to select sorted list of all DB processes memory utilization (VSZ), take the smallest one and subtract the figure from others processes VSZ. This method assume, that smallest process use all shared memory as others DB processes, but privet part is insignificant. Doesn’t work if you using JVM.
"Prem Khanna J" <premj_at_rediffmail.com>
Sent by: oracle-l-bounce_at_freelists.org
09.07.2004 08:05
Please respond to oracle-l
To: oracle-l_at_freelists.org
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Subject: private memory used by oracle process in AIX ??
Hi All,
the env is oracle 9.2.0.4/AIX5.2
# ps v 1495162
PID PGIN SIZE RSS LIM TSIZ TRS %CPU %MEM COMMAND
1495162 40 9068 32272 xx 48602 23204 0.0 1.0 ora_pmon
which will give me the private memory of the above process :
RSS - TRS
or
(RSS - TRS )*4
RSS & TRS are reported in kb. whereas an AIX memory page is 4096 bytes.
doc 123754.1 seems to be confusing.
it says to mulitply the difference by 4 , where as it doesn't in the
example shown in the doc.
can someone guide me which is the right way ?
Regards,
Prem.
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