RE: Oracle processes using more than 350Mb memory

You didn't mention what platform / OS you're running (always include that info!), but based on your mention of 'top', I'm going to guess it's a flavor of unix.  

top doesn't accurately represent the size of an Oracle process, cause all oracle processes attach to the SGA's shared memory segments, so, they all report a larger amount of memory than that individual process is actually consuming. If you have a 1/2 GB SGA, and there are 100 oracle processes, using reporting tools like top, you may think Oracle processes are consuming 51200MB of RAM. On a box w/ 2GB of RAM, clearly, that can't be right. That's cause that 512MB of RAM dedicated to the SGA got counted in every oracle process's memory map, but it's shared, it's only in memory once.  

On Solaris (and probably other flavors of unix), try: pmap -x <pid of oracle process>  

Look at the pmap output, and discard the line(s) where the shared memory is counted. That will give you a better idea of per process memory usage.  

Hope that helps,  

-Mark  

PS There was very recently a lengthy thread about the inadequacies of memory accounting under Linux. If you're on Linux, you may want to search the archives for that thread.  

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Mark J. Bobak

Senior Oracle Architect

ProQuest Information & Learning

There is nothing so useless as doing efficiently that which shouldn't be done at all. -Peter F. Drucker, 1909-2005  

From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Vijaya Vardhineni Sent: Thursday, October 12, 2006 7:41 PM To: oracle-l_at_freelists.org
Subject: Oracle processes using more than 350Mb memory

Hi
  On one of our database servers, we just have only one Oracle 9.2.0.6 database with the following memory parameters.  

pga_aggregate_target=104857600
shared_pool_size = 117440512
db_cache_size=251658240
large_pool_size=16777216
java_pool_size=67108864  

Top shows that some of the oracle processes are taking more than 350Mb memory. These are not the back ground processes associated with the instance. Database server has only 2Gb RAM. Can someone explain me what could be causing such a high memory usage.  

Regards
Vijay  

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http://www.freelists.org/webpage/oracle-l Received on Thu Oct 12 2006 - 19:06:48 CDT