Re: CISC to RISC and Excessive Logical I/O

["Mark Phippard" <MarkP@xxxxxxxxxxxxxxx>]

Tom,

Do a DSPFD on the PF and all of its associated LF's and look at the Access
Path Size (ACCPTHSIZ) parameter.  If the PF and LF's do not have the same
value in this field, it can cause performance problems.  For best
performance, IBM recommends you change the value to *MAX1TB on all files.

Maybe the PF came over with *MAX4GB and the LF's have been created on the
RISC box with the new default of *MAX1TB?

Hope this helps.

Mark Phippard




                                                                                
                                    
                    "Law, Tom"                                                  
                                    
                    <actlaw@NMHG.com>          To:     MIDRANGE-L 
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                    owner-midrange-l@mi        Subject:     CISC to RISC and 
Excessive Logical I/O                  
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                    06/20/01 09:08 AM                                           
                                    
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We are doing a CISC to RISC conversion from version 3.2 to 4.5.  We are
having some slow response times in some transactions.  We were finding that
DB CPU was getting upwards of 100%.  When looking at the traces (PEX,
performance, smtrace, DBmonitor), we found that simple transactions were
getting upwards of 100,000 to over a 1,000,000 logicals I/O's with less
than
320 SYNC reads.  The same functions on the CISC systems were usually less
than a 1,000 and no problems.

Data was restored to the RISC systems using the backup created from the
UPGRADE2 function on the CISC box.  I used the RSTLIB command for the data
libraries.  The data looks correct after the restore.  The only thing I can
think of that is common among different transactions is that the logicals
are not correct.  Could the logicals be the culprit?

We have had IBM look at the problem, but so far it can't be explained.

Any info would be greatly appreciated.

Thanks

Thomas A. Law Jr.

Sr. Systems Programmer

NACCO Materials Handling Group, Inc.
Americas MIS - Danville
1813 E. Voorhees St.
Danville, IL. 61832
217-443-7622
217-443-7657 Fax
217-444-9936 Pager
E-mail: actlaw@nmhg.com

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