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db2_awe and more than 4GB memory on Windows

P: n/a
Hi!

This may seems to be a stupid question but I can't figure out how
configuration of more than 4 GB memory on Windows works.

dbset db2_awe=1,<number of physical pages>, <number of address windows>
The first parameter is bufferpool id.

I have 15 databases in my instance each with a bufferpool with id = 1

Since this parameter is set on the instance level my question is:

Will all bufferpools with id 1 benefit from this?

If not - which database will be affected?

I can't see any improvments anywhere

Nov 12 '05 #1
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9 Replies


P: n/a
thomasb wrote:
Hi!

This may seems to be a stupid question but I can't figure out how
configuration of more than 4 GB memory on Windows works.

dbset db2_awe=1,<number of physical pages>, <number of address windows>
The first parameter is bufferpool id.

I have 15 databases in my instance each with a bufferpool with id = 1

Since this parameter is set on the instance level my question is:

Will all bufferpools with id 1 benefit from this?

If not - which database will be affected?

I can't see any improvments anywhere

Thomas,

I think got that one right.

Personally I'm not a fan of AWE. IMHO AWE is a kludge in Windows to
begin with....

--
Serge Rielau
DB2 SQL Compiler Development
IBM Toronto Lab
Nov 12 '05 #2

P: n/a
thomasb wrote:
Hi!

This may seems to be a stupid question but I can't figure out how
configuration of more than 4 GB memory on Windows works.


afaik windows doesn't support > 4GB mem. Or is it a 64bit windows
version? (Don't know about that).

-R-
Nov 12 '05 #3

P: n/a
Jurgen Haan wrote:
thomasb wrote:
Hi!

This may seems to be a stupid question but I can't figure out how
configuration of more than 4 GB memory on Windows works.


afaik windows doesn't support > 4GB mem. Or is it a 64bit windows
version? (Don't know about that).

-R-

Not quite, you can go to up to 64 GB on Windows 2003 Data Center.
Haven't tried it though.
--
Anton Versteeg
IBM Netherlands
Nov 12 '05 #4

P: n/a
Anton Versteeg wrote:
Not quite, you can go to up to 64 GB on Windows 2003 Data Center.
Haven't tried it though.


Provided you run it on a ia64 I assume?
x86 does not allow adressing > 4GB mem... Or does windows use a trick to
bypass buswidth?

-R-
Nov 12 '05 #5

P: n/a
Jurgen Haan wrote:
Anton Versteeg wrote:
Not quite, you can go to up to 64 GB on Windows 2003 Data Center.
Haven't tried it though.

Provided you run it on a ia64 I assume?
x86 does not allow adressing > 4GB mem... Or does windows use a trick to
bypass buswidth?

-R-

No, that's on 32-bit hardware and yes Windows does some tricks.
If I am correct you loose about 1GB of the memory under 4GB.
And for the average 32-bit application it won't be easy to address the
storage over 4GB.

--
Anton Versteeg
IBM Netherlands
Nov 12 '05 #6

P: n/a
Anton Versteeg wrote:
No, that's on 32-bit hardware and yes Windows does some tricks.
If I am correct you loose about 1GB of the memory under 4GB.
And for the average 32-bit application it won't be easy to address the
storage over 4GB.


LOL.. Didn't know that.. Thanks :)

-R-
Nov 12 '05 #7

P: n/a
Finally found out how to activate memory above 4 GB on a Windows 2003
AdSrv box but run into another strange (for me) problem.

db2_awe=2,2000000,250000

I want to lock 8GB of memory through a 1GB window for bufferpooll #2
(The parameter is set at instance level)

Create bufferpool bigbp

CREATE BUFFERPOOL BIGBP IMMEDIATE SIZE 1000000 PAGESIZE 4 K ;

Stop and start the dabase manager

Around 700 MB of memory is used

Connect to the database with bufferpool BIGBP

8,7 GB of memory is allocated

OK I have a 4 GB big BP and have wasted 8 GB of memory

hmmm!!!

DROP BUFFERPOOL BIGBP;

CREATE BUFFERPOOL BIGBP IMMEDIATE SIZE 2000000 PAGESIZE 4 K ;

Error!!!!!!

[IBM][CLI Driver][DB2/NT] SQL0644N Invalid value specified for
keyword "SIZE" in statement "BUFFERPOOL". SQLSTATE=42615

So I can allocate the memory but don't use it! Strange!

Can't find any information in the administrator's manual about an
upper limit for the SIZE parameter.

I'm confused!

Any input in this matter is appreciated

Nov 12 '05 #8

P: n/a
Ian
thomasb wrote:
Finally found out how to activate memory above 4 GB on a Windows 2003
AdSrv box but run into another strange (for me) problem.

db2_awe=2,2000000,250000


When you use DB2_AWE, the registry variable sets the size of the
bufferpool with the ID you specified. Using DB2_AWE _overrides_ the
size of the bufferpool that is defined in the catalog.

So assuming that the bufferpool with bufferpoolid = 2 has 4K page
size, the bufferpool will have a size of 7.6 Gb , accessed through
an AWE window of ~976 Mb (regardless of the value of npages in
syscat.bufferpools).

Nov 12 '05 #9

P: n/a
Ian skrev:
When you use DB2_AWE, the registry variable sets the size of the
bufferpool with the ID you specified. Using DB2_AWE _overrides_ the
size of the bufferpool that is defined in the catalog.

So assuming that the bufferpool with bufferpoolid = 2 has 4K page
size, the bufferpool will have a size of 7.6 Gb , accessed through
an AWE window of ~976 Mb (regardless of the value of npages in
syscat.bufferpools).


Aha!!

Thanks Ian!

I thought it was kind of a two step process. First allocate memory and
then define the bufferpool inside that memory container

Nov 12 '05 #10

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