Bufferpool size Problem

[Christian Berg]

Hi,

I have got a problem with resizing the bufferpool of a DB2 v.8.2
instance.

The DB2 runs on an AIX 5.x platform.

Problem is that an "ALTER BUFFERPOOL ..." command is not persistent if
the database is stopped with the db2stop and restarted with the
db2start command.

The bufferpool which I try to resize is the IBMDEFAULTBP.

Another problem that occurs is that all DB instances use the same
large bufferpoolsize when allocating memory although their size is set
to default value (1000 pages - IBMDEFAULTBP).

I once set that value of IBMDEFAULTBTP to 131072 and now every
Bufferpool on that DB2 instance seems to use that value despite the
actual setting of the DB-instances.

I see no way on how to change the value of the bufferpool and this
leads the AIX to crash if many instances are activated because all the
memory is allocated.

Hope someone can help me ...

Greetings
Christian Berg

[Jsoh]

> Problem is that an "ALTER BUFFERPOOL ..." command is not persistent if

the database is stopped with the db2stop and restarted with the
db2start command.
That is most assuredly not the case. First of all, ALTER BUFFERPOOL is
an SQL statement, not a command. Are you sure that are committing the
ALTER BUFFERPOOL statement?

In fact, the only way that I can duplicate this behavior is if I issue
an ALTER BUFFERPOOL statement, not commit it, and then do a 'db2stop
force' in another window. In that case, the transaction gets rolled
back, and the bufferpool remains at its original size.
Another problem that occurs is that all DB instances use the same
large bufferpoolsize when allocating memory although their size is set
to default value (1000 pages - IBMDEFAULTBP).

I once set that value of IBMDEFAULTBTP to 131072 and now every
Bufferpool on that DB2 instance seems to use that value despite the
actual setting of the DB-instances.

Err. Thats not right either. Bufferpools are (by definition)
database-local objects.

Changing the size of IBMDEFAULTBP via ALTER BUFFERPOOL will have zero
effect on the size of any other database on the instance. Even if you
were changing the BUFFPAGE database configuration parameter to change
the size of the bufferpool, that still wouldnt have an effect on other
db's in the instance.

jsoh