DB2 Instance Memory and dbptnmem

If you are using DB2 9.5 and need to track the memory usage of an instance , then db2pd -db2ptnmem displays the output of current memory and the highwater mark of the memory segments.

It is worth mentioning that with DB2 9.5 the INSTANCE_MEMORY becomes the memory allocation delimiter. If set at AUTOMATIC , at start up DB2 calculates
a certain percentage of Physical RAM , including some memory for an overflow buffer.If you are not setting it to AUTOMATIC , then set a value that alows DB2 to leaves space for other applications.

After the install of DB2 9.5 do an output of INSTANCE_MEMORY to view current configutation. The unit of measure is in 4K pages:

$db2 get dbm cfg | grep INSTANCE_MEMORY

Size of instance shared memory (4KB)  (INSTANCE_MEMORY) = AUTOMATIC(1048576)

When looking at the output of db2pd -dbptnmem  , note that Mem Used includes Cached.

$db2pd -dbptnmem

Database Partition 0 -- Active -- Up 0 days 15:02:00

Database Partition Memory Controller Statistics

Controller Automatic: Y
Memory Limit:         4194304 KB
Current usage:        4188544 KB
HWM usage:            4189760 KB
Cached memory:        113472 KB

Individual Memory Consumers:

Name             Mem Used (KB) HWM Used (KB) Cached (KB)
========================================================
APPL-REPORTER             1152        160000        1024
APPL-WAREHOUS             8768        160000        4608
DBMS-db2tdw              36928         43136         128
FMP_RESOURCES             1152          1152           0
PRIVATE                  32384         34496        8384
DB-WAREHOUS            2009664       2408320         896
DB-REPORTER            2098368       2098368       98432

 Ref:Jack Vamvas(http://www.dba-db2.com)