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configuration advisor on buffer pool size

hi, we are using db2 udb v8.1 on windows, i try to use the
configuration advisor to get recommendation on the parameter setting,
at first, i give the target memory for DB2 is 80% of the physical
memory, it gives me a recommendation on bufferpool size, so i accept
the change, later on , i found that i gave too much memory to DB2, so
i change the target lower, but the recommendation doesn't change the
buffer pool size accordingly, why is that? thanks
Nov 12 '05
36 4372
xixi,

if you want to change the db cfg buffpage parameter you have to update

db2 update db cfg for <db-name> using buffpage <size in 4k pages>

and then update the ibmdefaultbp in the CC to -1.

I think you have to stop and start the instance or disconnect all.

regards,
Joachim Müller

"xixi" <da****@yahoo.c om> schrieb im Newsbeitrag
news:c0******** *************** ***@posting.goo gle.com...
no, i am not creating a new bufferpool, i am change the bufferpool
size of ibmdefaultbf. in control center, you can have option to change
the size, and i saw the size changed immediately , but not under
configuraion parameter buffpage. i still don't understand why they
aren't consistent, i have to restart the instance in order to change
buffpage parameter to make the same as i alter the size of
ibmdefaultbf.

Nov 12 '05 #31
so if i only use control center to change the ibmdefaultbf size by
alter, is that enough? do i need to change the buffpage parameter by
doing update db cfg to let them consistent?

"Joachim Mueller" <jom0309@[--spam--]douglas-informatik.de> wrote in message news:<c7******* ***@news.dtag.d e>...
xixi,

if you want to change the db cfg buffpage parameter you have to update

db2 update db cfg for <db-name> using buffpage <size in 4k pages>

and then update the ibmdefaultbp in the CC to -1.

I think you have to stop and start the instance or disconnect all.

regards,
Joachim Müller

"xixi" <da****@yahoo.c om> schrieb im Newsbeitrag
news:c0******** *************** ***@posting.goo gle.com...
no, i am not creating a new bufferpool, i am change the bufferpool
size of ibmdefaultbf. in control center, you can have option to change
the size, and i saw the size changed immediately , but not under
configuraion parameter buffpage. i still don't understand why they
aren't consistent, i have to restart the instance in order to change
buffpage parameter to make the same as i alter the size of
ibmdefaultbf.

Nov 12 '05 #32
so if i only use control center to change the ibmdefaultbf size by
alter, is that enough? do i need to change the buffpage parameter by
doing update db cfg to let them consistent?

"Joachim Mueller" <jom0309@[--spam--]douglas-informatik.de> wrote in message news:<c7******* ***@news.dtag.d e>...
xixi,

if you want to change the db cfg buffpage parameter you have to update

db2 update db cfg for <db-name> using buffpage <size in 4k pages>

and then update the ibmdefaultbp in the CC to -1.

I think you have to stop and start the instance or disconnect all.

regards,
Joachim Müller

"xixi" <da****@yahoo.c om> schrieb im Newsbeitrag
news:c0******** *************** ***@posting.goo gle.com...
no, i am not creating a new bufferpool, i am change the bufferpool
size of ibmdefaultbf. in control center, you can have option to change
the size, and i saw the size changed immediately , but not under
configuraion parameter buffpage. i still don't understand why they
aren't consistent, i have to restart the instance in order to change
buffpage parameter to make the same as i alter the size of
ibmdefaultbf.

Nov 12 '05 #33
Ian
xixi wrote:
so if i only use control center to change the ibmdefaultbf size by
alter, is that enough? do i need to change the buffpage parameter by
doing update db cfg to let them consistent?


The BUFFPAGE database config parameter is a holdover from DB2 V2.1. It
is used to define the size (number of pages) of any bufferpool IF and
only if the NPAGES value in SYSCAT.BUFFERPO OLS is -1. This applies to
_all_ bufferpools where NPAGES = -1, not just IBMDEFAULTBP.

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Nov 12 '05 #34
Ian
xixi wrote:
so if i only use control center to change the ibmdefaultbf size by
alter, is that enough? do i need to change the buffpage parameter by
doing update db cfg to let them consistent?


The BUFFPAGE database config parameter is a holdover from DB2 V2.1. It
is used to define the size (number of pages) of any bufferpool IF and
only if the NPAGES value in SYSCAT.BUFFERPO OLS is -1. This applies to
_all_ bufferpools where NPAGES = -1, not just IBMDEFAULTBP.

-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----
Nov 12 '05 #35
"xixi" <da****@yahoo.c om> wrote in message
news:c0******** *************** ***@posting.goo gle.com...
so if i only use control center to change the ibmdefaultbf size by
alter, is that enough? do i need to change the buffpage parameter by
doing update db cfg to let them consistent?

Ignore the buffpage parm, and just set each bufferpool the size you want it
with alter bufferpool (or use control center). Just leave buffpage the way
it is.
Nov 12 '05 #36
"xixi" <da****@yahoo.c om> wrote in message
news:c0******** *************** ***@posting.goo gle.com...
so if i only use control center to change the ibmdefaultbf size by
alter, is that enough? do i need to change the buffpage parameter by
doing update db cfg to let them consistent?

Ignore the buffpage parm, and just set each bufferpool the size you want it
with alter bufferpool (or use control center). Just leave buffpage the way
it is.
Nov 12 '05 #37

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