Hi Beena,

Prior to Viper II (9.5), db2mtrk using the high-water mark is your
best bet, but will not include all memory consumed by the instance.
As well, the results may be misleading - you will not necessarily hit
the high watermark for all heaps at the same time, and some heaps will
come and go during operation (i.e. each new connection that comes in
will require a new application heap).

If you're on Viper II or later though, there is a new table function
that will tell you exactly what you want - admin_get_dbp_mem_usage().
That will tell you the most memory the instance is allowed to consume,
the current memory that is being consumed by the instance, and the
peak/high watermark of memory consumed by the instance since db2start.

Cheers,
Liam.