excessive memory utilization after upgrade to 11G

Memory Footprint For Dedicated Server Processes More Than Doubled After 11g Upgrade On AIX Platform [ID 1246995.1]

Applies to:
Oracle Server - Enterprise Edition - Version: 11.2.0.1 and later   [Release: 11.2 and later ]
IBM AIX on POWER Systems (64-bit)
Symptoms
o  After upgrade to Oracle release 11g (11.2.0.1.0 or 11.2.0.2.0),  the machine hung due to excessive memory utilization increase for each dedicated server process.

o svmon on oracle OS process id shows size of USLA, User-Space Loader Assistant, heap of about 7M bytes  running Oracle release 11.2.0.1.0 on AIX platform:

svmon -P PID  - where PID is an Oracle process id

Oracle Release ->  (work USLA heap times 4k pages size)

11.2.0.1.0 -> 7M bytes
11.1.0.7.0 -> 60KB
10.2.0.4.0 -> 420KB




Changes
Upgrade to Oracle release 11g (11.2.0.1.0 or 11.2.0.2.0)  from an earlier release 10g or 9i running on AIX platform.
Cause
This is bug 10211065 which is set to duplicate of base bug 9796810 and 10190759:

Bug 10211065.-P Base Bug 9796810
Abstract: MEMORY FOOTPRINT FOR DEDICATED SERVER PROCESSES MORE THAN DOUBLED AFTER 11G UGP

Bug 9796810.-P Base Bug 10190759
Abstract: 11G SERVER PROCESSES CONSUMING MUCH MORE MEMORY THAT 10G OR 9I

Bug 10190759.-P
Abstract:  PROCESSES CONSUMING ADDITIONAL MEMORY DUE TO 'USLA HEAP'

Oracle process consumes significantly more memory compared to earlier
releases. Utilizing the svmon command on AIX it can be seen that most of
this memory additional memory is under "Work USLA Heap" category.


Solution
If you find the memory footprint on your oracle processes has significantly
increased compared to previous releases and you are running on the AIX
platform you have likely encountered this issue.

To verify if you are hitting this issue, you can collect following information:

a) Choose one PID for a oracleSID process then execute:

svmon -P PID
genld -ld | more | /PID
procldd PID
procmap PID

b)  cd $ORACLE_HOME/bin
ls -lL oracle
ldd oracle


The additional memory seen allocated to oracle processes in the 11.2 release
is a consequence of the additional link options added to the oracle link
line, -bexpfull and -brtllib. The two link options were specifically added
in 11.2.0.1 to support the online patching feature.

Changes in the make file have been implemented such that you
can relink without these options (-bexpfull and -brtllib) to avoid
additional memory overhead incurred by adding these options.
These changes are available via a one-off patch.

To check for Patch Availability from My Oracle Support:

1) Enter Patch Name or Number: 10190759
2) Enter Platform: IBM AIX on POWER Systems (64-bit)

Note that the default behavior to install the patch, opatch apply, or link oracle
is WITHOUT the options brtllib and bexpfull:

make -f ins_rdbms.mk 'EXP_OPTS=$(EXP_OPTS_OFF)' ioracle
or
make -f ins_rdbms.mk ioracle


To relink oracle with these options you can execute the following on the command line to accomplish this:

make -f ins_rdbms.mk 'EXP_OPTS=$(EXP_OPTS_ON)' ioracle


The fix provided here is only seen as interim solution for the problem until such time
as a fix is provided for the run time loader on AIX by IBM.




References
BUG:10190759 - PROCESSES CONSUMING ADDITIONAL MEMORY DUE TO 'USLA HEAP'
BUG:10211065 - MEMORY FOOTPRINT FOR DEDICATED SERVER PROCESSES MORE THAN DOUBLED AFTER 11G UGP
BUG:9796810 - 11G SERVER PROCESSES CONSUMING MUCH MORE MEMORY THAT 10G OR 9I