Re: Why separate pools? -- MIDRANGE-L

How does one make a determination on what is a "shared pool" and should be 
set to *CALC?

              Defined    Max   Allocated   Pool  -Paging Option--
Pool         Size (M)  Active  Size (M)     ID   Defined  Current
*MACHINE      1407.56   +++++     1407.56    1   *FIXED   *FIXED 
*BASE         6670.02    1337     6670.02    2   *CALC    *CALC 
*INTERACT     4871.39     458     4871.39    3   *FIXED   *FIXED 
*SPOOL         269.19      46      269.19    5   *FIXED   *FIXED 
*SHRPOOL1     5083.87      80     5083.87    4   *CALC    *CALC 

Rob Berendt
-- 
Group Dekko Services, LLC
Dept 01.073
PO Box 2000
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com





Vernon Hamberg <vhamberg@xxxxxxxxxxx> 
Sent by: midrange-l-bounces@xxxxxxxxxxxx
11/24/2004 01:50 AM
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Subject
Re: Why separate pools?






I stronlgy recommend that you set all shared pools to *CALC. This is 
expert 
cache, and it affects the I/O block size for transferring data from DASD. 
*FIXED forces this size to 4K (and maybe 16K for SQL indexes, or something 

like that), but it is possible to have a block size as large as 128K. 
Expert cache uses a sliding window (about 4 minutes, I think) for 
measuring 
disk I/O in regard to data files. The database engine reports its I/Os to 
expert cache, which changes the block size, depending on whether access to 

data is completely sequential (large block size, since everything is 
contiguous on disk), to completely random access, where records are 
accessed by key and are not located close together on disk.

There can be tremendous gains in I/O - the actual time to bring in a block 

of any size is essentially the same, so the more you can transfer in a 
request the better.

You can see some of these numbers in WRKDSKSTS. There are 3 columns that 
report request size - the one in the middle is average size for both reads 

and writes. To the right are separate columns for each operation.

HTH
Vern

At 12:43 PM 11/23/2004, you wrote:
>Regarding wrkshrpool, F11 paging options, *FIXED vs. *CALC.
>
>Two questions:
>
>1) If qpfradj is 2 or 3 and all the wrkshrpool paging options are *FIXED,
>doesn't the performance adjuster still continue to move ram between the
>pools with the page size remaining the same (*FIXED) across all pools (at
>4k ? - or whatever size the pages are)?
>
>2) If *FIXED is changed to *CALC,  isn't this what the manuals refer to 
as
>'expert cache'? And doesn't that mean the expert cache only affects the
>calculation of the page size within that pool, (which indirectly affects
>the amount of ram moved in/out of the pool)?
>
>
>Regards, Jerry
>
>Gerald Kern
>IBM Certified AS/400 RPG IV Developer & RPG IV Programmer
>MIS Project Leader, Lotus Notes/Domino Administrator
>The Toledo Clinic, Inc.
>4235 Secor Road
>Toledo, OH 43623-4299
>Phone 419-479-5535
>gkern@xxxxxxxxxxxxxxxx

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