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.
***--*
*Mark J. Bobak*
*Senior Oracle Architect*
***P****ro****Q****uest 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@xxxxxxxxxxxxx [mailto:
oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Vijaya Vardhineni
*Sent:* Thursday, October 12, 2006 7:41 PM
*To:* oracle-l@xxxxxxxxxxxxx
*Subject:* Oracle processes using more than 350Mb memory
Hi
On one of our database servers, we just have only one Oracle 9.2.0.6database
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
