Connecting Tech Pros Worldwide Help | Site Map

DB2 - forcing a table to cache all data in the buffer pool.

  #1  
Old November 3rd, 2008, 08:55 PM
Patrick Finnegan
Guest
 
Posts: n/a
Is there a DB2 setting that will force a table to be cached in
the
buffer pool? We have four tables that we want to cache completely
in
the buffer pool to ensure that all the data is read from memory.
The
buffer pool ratio should be close to 100%. It's about 80% at the
moment.

Would a "select all" statement cache everything in the table?
  #2  
Old November 3rd, 2008, 09:35 PM
Ian
Guest
 
Posts: n/a

re: DB2 - forcing a table to cache all data in the buffer pool.


Patrick Finnegan wrote:
Quote:
Is there a DB2 setting that will force a table to be cached in
the
buffer pool? We have four tables that we want to cache completely
in
the buffer pool to ensure that all the data is read from memory.
The
buffer pool ratio should be close to 100%. It's about 80% at the
moment.
>
Would a "select all" statement cache everything in the table?
There is no setting for pinning a table into the bufferpool.
I fail to see why you would need to do this -- when you get
into the job of trying to outsmart the DBMS, something is
usually wrong.

Regardless, if your bufferpools are large enough, pinning will
effectively happen. You may need to put each table into
a separate tablespace, and assign each tablespace to its own
unique bufferpool.

  #3  
Old November 3rd, 2008, 10:05 PM
Serge Rielau
Guest
 
Posts: n/a

re: DB2 - forcing a table to cache all data in the buffer pool.


Ian wrote:
Quote:
Patrick Finnegan wrote:
Quote:
>Is there a DB2 setting that will force a table to be cached in
>the
>buffer pool? We have four tables that we want to cache completely
>in
>the buffer pool to ensure that all the data is read from memory.
>The
>buffer pool ratio should be close to 100%. It's about 80% at the
>moment.
>>
>Would a "select all" statement cache everything in the table?
>
There is no setting for pinning a table into the bufferpool.
Well, there is. You describe it below.
Quote:
put each table into
a separate tablespace, and assign each tablespace to its own
unique bufferpool.
Just make sure the BP size >= tablespace size

Cheers
Serge

--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab
  #4  
Old November 4th, 2008, 08:05 AM
Patrick Finnegan
Guest
 
Posts: n/a

re: DB2 - forcing a table to cache all data in the buffer pool.


On Nov 3, 9:58*pm, Serge Rielau <srie...@ca.ibm.comwrote:
Quote:
Ian wrote:
Quote:
Patrick Finnegan wrote:
Quote:
Is there a DB2 setting that will force a table to be cached in
the
buffer pool? *We have four tables that we want to cache completely
in
the buffer pool to ensure that all the data is read from memory.
The
buffer pool ratio should be close to 100%. *It's about 80% at the
moment.
>
Quote:
Quote:
Would a "select all" *statement cache everything in the table?
>
Quote:
There is no setting for pinning a table into the bufferpool.
>
Well, there is. You describe it below.put each table into
Quote:
a separate tablespace, and assign each tablespace to its own
unique bufferpool.
>
Just make sure the BP size >= tablespace size
>
Cheers
Serge
>
--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab
Thanks. I will try that.

  #5  
Old November 4th, 2008, 11:55 AM
Serge Rielau
Guest
 
Posts: n/a

re: DB2 - forcing a table to cache all data in the buffer pool.


The discussion so far was about pinning a table in the bufferpool.
What you describe here is a way to pinning buffer pool in memory.
Two different kinds of page faults.

Cheers
Serge

--
Serge Rielau
DB2 Solutions Development
IBM Toronto Lab
Closed Thread


Similar Threads
Thread Thread Starter Forum Replies Last Post
MESSAGE : Unable to find donor to satisfy minSize constraint nimjerry answers 0 March 6th, 2008 03:55 PM
DB2 crash?!? Jurgen Haan answers 14 November 12th, 2005 10:39 AM
Direct reads & In memory Database Alex Greem answers 10 November 12th, 2005 09:00 AM
Meaning of direct_writes in tablespace snapshot Jean-Marc Blaise answers 13 November 12th, 2005 08:56 AM
Configuring Multiple Instances DB2 WINNT Mike answers 11 November 12th, 2005 07:27 AM