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how to change the bufferpool size correctly?

P: n/a
hi, we are using db2 udb v8.1 on windows, normally i would use control
center to change bufferpool size since i know the change will be
effect immediately for version 8.1, so i right click bufferpool, do
alter, change the size (to a smaller one), after that , i use the
configuration parameter to check the bufferpool size, it still show
the old value, i close the control center and reopen , still the same,
so is that i must stop the instance in order to pick up the right
value?
Nov 12 '05 #1
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10 Replies


P: n/a
A bufferpool change won't take effect until a time when there are no
active connections. Is there a refresh option in the Control Center?

xixi wrote:
hi, we are using db2 udb v8.1 on windows, normally i would use control
center to change bufferpool size since i know the change will be
effect immediately for version 8.1, so i right click bufferpool, do
alter, change the size (to a smaller one), after that , i use the
configuration parameter to check the bufferpool size, it still show
the old value, i close the control center and reopen , still the same,
so is that i must stop the instance in order to pick up the right
value?


Nov 12 '05 #2

P: n/a
A bufferpool change won't take effect until a time when there are no
active connections. Is there a refresh option in the Control Center?

xixi wrote:
hi, we are using db2 udb v8.1 on windows, normally i would use control
center to change bufferpool size since i know the change will be
effect immediately for version 8.1, so i right click bufferpool, do
alter, change the size (to a smaller one), after that , i use the
configuration parameter to check the bufferpool size, it still show
the old value, i close the control center and reopen , still the same,
so is that i must stop the instance in order to pick up the right
value?


Nov 12 '05 #3

P: n/a
Blair Adamache <ba*******@2muchspam.yahoo.com> wrote in message news:<c6**********@hanover.torolab.ibm.com>...
A bufferpool change won't take effect until a time when there are no
active connections. Is there a refresh option in the Control Center?


Not strictly true. Changes to the size of a buffer pool default to being IMMEDIATE
unless otherwise specified, or (in the case of an increase in size), the db
shared set isnt big enough to contain the new size.
hi, we are using db2 udb v8.1 on windows, normally i would use control
center to change bufferpool size since i know the change will be
effect immediately for version 8.1, so i right click bufferpool, do
alter, change the size (to a smaller one), after that , i use the
configuration parameter to check the bufferpool size, it still show
the old value, i close the control center and reopen , still the same,
so is that i must stop the instance in order to pick up the right
value?


You make reference to 'configuration parameter' - I presume that you are looking
at the value of BUFFPAGE? This wouldnt change - you havent modified it. BUFFPAGE
only affects buffer pools which have a size listed of -1. See the documentation
for more information

hj
Nov 12 '05 #4

P: n/a
Blair Adamache <ba*******@2muchspam.yahoo.com> wrote in message news:<c6**********@hanover.torolab.ibm.com>...
A bufferpool change won't take effect until a time when there are no
active connections. Is there a refresh option in the Control Center?


Not strictly true. Changes to the size of a buffer pool default to being IMMEDIATE
unless otherwise specified, or (in the case of an increase in size), the db
shared set isnt big enough to contain the new size.
hi, we are using db2 udb v8.1 on windows, normally i would use control
center to change bufferpool size since i know the change will be
effect immediately for version 8.1, so i right click bufferpool, do
alter, change the size (to a smaller one), after that , i use the
configuration parameter to check the bufferpool size, it still show
the old value, i close the control center and reopen , still the same,
so is that i must stop the instance in order to pick up the right
value?


You make reference to 'configuration parameter' - I presume that you are looking
at the value of BUFFPAGE? This wouldnt change - you havent modified it. BUFFPAGE
only affects buffer pools which have a size listed of -1. See the documentation
for more information

hj
Nov 12 '05 #5

P: n/a
so does that means i shouldn't manually change the buffpage parameter
to the same as ibmdefaultbf size?
Nov 12 '05 #6

P: n/a
so does that means i shouldn't manually change the buffpage parameter
to the same as ibmdefaultbf size?
Nov 12 '05 #7

P: n/a
> so does that means i shouldn't manually change the buffpage parameter
to the same as ibmdefaultbf size?


Unless you want to change the size of all bufferpools which have a size of -1
(ie, use BUFFPAGE as the size), then there's no reason to change BUFFPAGE when
you alter the size of ibmdefaultbp

hj
Nov 12 '05 #8

P: n/a
> so does that means i shouldn't manually change the buffpage parameter
to the same as ibmdefaultbf size?


Unless you want to change the size of all bufferpools which have a size of -1
(ie, use BUFFPAGE as the size), then there's no reason to change BUFFPAGE when
you alter the size of ibmdefaultbp

hj
Nov 12 '05 #9

P: n/a
the change of buffpage parameter default is 250, then after i load the
database data, i do a configuration advisor, it recommend change the
buffpage to new value, so i accept it and saw the change affected
buffpage parameter and ibmdefaultbf size, if as you said, buffpage
prameter change only affect bufferpools with a size of -1, why the
configuration adviseo change buffpage parameter? this makes me
confusing since i have thought alter bufferpool size and update db cfg
buffpage is same thing.

go****@zipperup.org (Hildy Johnson) wrote in message news:<2e**************************@posting.google. com>...
so does that means i shouldn't manually change the buffpage parameter
to the same as ibmdefaultbf size?


Unless you want to change the size of all bufferpools which have a size of -1
(ie, use BUFFPAGE as the size), then there's no reason to change BUFFPAGE when
you alter the size of ibmdefaultbp

hj

Nov 12 '05 #10

P: n/a
the change of buffpage parameter default is 250, then after i load the
database data, i do a configuration advisor, it recommend change the
buffpage to new value, so i accept it and saw the change affected
buffpage parameter and ibmdefaultbf size, if as you said, buffpage
prameter change only affect bufferpools with a size of -1, why the
configuration adviseo change buffpage parameter? this makes me
confusing since i have thought alter bufferpool size and update db cfg
buffpage is same thing.

go****@zipperup.org (Hildy Johnson) wrote in message news:<2e**************************@posting.google. com>...
so does that means i shouldn't manually change the buffpage parameter
to the same as ibmdefaultbf size?


Unless you want to change the size of all bufferpools which have a size of -1
(ie, use BUFFPAGE as the size), then there's no reason to change BUFFPAGE when
you alter the size of ibmdefaultbp

hj

Nov 12 '05 #11

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