Why oracle.exe using so much "Mem Usage" and "VM Size"?

Posted on 2006-04-28
Medium Priority
Last Modified: 2013-12-11
I have been noticing this recently in my computer: Eventhough I'm not running any application or program related to ORACLE, oracle.exe gives me high number of memory and virtual memory size.

The last time I checked the task manager right after I restarted my computer:
The "Mem Usage" is 97, 488
and the "VM Size" is 169, 888 K

I'm pretty new with using ORACLE. Is the mem usage and the VM size this big supposed to be normal?

Thanks in advance for the help.
Question by:rnicholus
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Expert Comment

ID: 16568499
Dear rnicholus,
 On windows environment Oracle.exe is the process having many subprocesses inside it (background processes and parallel thread processes) which responsible for user query response,  if you will shutdown oracle database the its service using shutdown command this will disappear.

Moreover its used memory size can be limited by decreasing database parameter sga_max_size and pga_aggregate_target.

Haider Ali Syed
Sr. IT Exective Databases

Author Comment

ID: 16581105
Hello Haider,

Thanks for the lead.
I'll get back to this asap.
LVL 48

Expert Comment

ID: 16595006
970 MB memory.
This depends of the SGA the DBA has assigned to this instance.
To see the real size of the SGA components either use OEM or
SQL> show sga

Total System Global Area  289406976 bytes
Fixed Size                  1260420 bytes
Variable Size             109053052 bytes
Database Buffers          171966464 bytes
Redo Buffers                7127040 bytes
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Author Comment

ID: 16601068

I have two questions now:
1. Is restarting the computer should actually help? Because it seems that it doesn't in my case.
2. Haider: I have tried to restart the OracleServiceSTARTDB and OracleOraHome92TNSListener a number of times but it doesn't help also. Is this what you mean?

Thanks for the help.
LVL 48

Assisted Solution

schwertner earned 150 total points
ID: 16603109
There is a famous old respectable expert here - Mark Geerlings. He also mentioned that they reboot the machine (not Oracle) once weekly. I also suffer on Windows 2000 2 years  (9i) this phenoma and couldn't find resolution. From November 2005 we have Windows XP Professional and Oracle and we have no complains. Oracle runs smoothly ...

Expert Comment

ID: 16617286
What you are seeing is normal, restarting oracle or the box will have no effect.
Oracle will grab the amount of SGA you have configured, (whether you run any programs or not, this gets pre-allocated) and the server processes will use this memory.

There would be some more memory requirements (PGA) once you start some programs that access the database.

If your other applications are suffering because of low memory you might want to reduce the SGA by changing init.ora parameters, but this might adversely affect your database performance.
LVL 48

Expert Comment

ID: 16628572
Investigate the size of the SGA. In Windows it should not be greater
the the half of the physical RAM.

Please publish the size of the SGA, number of instances on the box and the size of the RAM.

As said (I suffer 2 years) W2000 is not the best for Oracle servers (i met often 100% CPU usage).

Accepted Solution

haidersyed earned 900 total points
ID: 16628621
Ok after logging in as DBA user system or sys

give command
sql> Sho sga

smaple output is

Total System Global Area 1702363268 bytes
Fixed Size                   458116 bytes
Variable Size             654311424 bytes
Database Buffers         1056964608 bytes
Redo Buffers               10629120 bytes

sho parameter db_cache_size

(if oracle 9i is there)
for 8i

sho parameter db_buffer

This database sga is about 1.6 GB (from tatal global area size 1702363268 )

Now you can change it to any less value by

1- please backup your dbs and database folder to some location

for oracle 9i

2- log in as SYSDBA

3- Alter system set sga_max_size=1400M scope=spfile;
4- Alter system set db_cache_size= (any value less then returen from db_cahce_size ) scope=spfile

sql> shutdown immediate
sql > startup


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