DB2 total memory allocation

meehange · #1 (**permalink**) 08-12-07, 21:23

DB2 8.2 AIX 5.3

Hey guys....what's the best way to determine the TOTAL amount of memory allocated for a DB/Instance?

I've been trying out db2mtrk -i -d -v -m but the total figure it gives me is way up in the hundreds of GBs so I'm not sure exactly how it arrives at that number.

Marcus_A · #2 (**permalink**) 08-13-07, 03:19

Can you post the output of db2mtrk here? You may not be reading it correctly.

meehange · #3 (**permalink**) 08-13-07, 22:00

Sure:

Code:

   Backup/Restore/Util Heap has max size of 4112384 bytes
   Package Cache has max size of 18253611008 bytes
   Catalog Cache Heap has max size of 18253611008 bytes
   Buffer Pool Heap has max size of 18253611008 bytes
   Buffer Pool Heap has max size of 18253611008 bytes
   Buffer Pool Heap has max size of 18253611008 bytes
   Buffer Pool Heap has max size of 18253611008 bytes
   Buffer Pool Heap has max size of 18253611008 bytes
   Buffer Pool Heap has max size of 18253611008 bytes
   Lock Manager Heap has max size of 44187648 bytes
   Database Heap has max size of 78905344 bytes
   Other Memory has max size of 12353536 bytes
   Total: 146168446976 bytes

So I read that as the total amount of memory configured is 146168446976 bytes which is 136 GB...no?

Marcus_A · #4 (**permalink**) 08-13-07, 23:32

You are using the -m parm, which shows the maximum values that could possibly be configured for each pool, not the actual values being used. Omit the -m parm and try again.

meehange · #5 (**permalink**) 08-14-07, 01:13

OK but will that give me "Currently in use" or "Currently configured"?

I want to know the maximum memory that DB2 could use based on the currently configured params....

Marcus_A · #6 (**permalink**) 08-14-07, 03:49

Quote:

Originally Posted by meehange

OK but will that give me "Currently in use" or "Currently configured"?

I want to know the maximum memory that DB2 could use based on the currently configured params....

Just leave off the the -m. Using the -m does not show the maximum that could be used with your current configuration, it shows the maximum memory that would be used if you set all the configurations and bufferpool sizes to their maximum values.

Of course, the amount of memory used could vary dynamically depending on the number of connections and other activity, but the overwhelming majority of the memory is usually for the bufferpools, which do not increase beyond the defined amount (and do not shrink so long as someone is connected to the database). The only exception might be if you are using automatic memory in Version 9.

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