RE: Inconsistent performance

The little note at the bottom of that link:
<snip> IBM i intends to remove the SQE_NATIVE_ACCESS control in the release after IBM i 7.3.</snip>
Came true.
https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_74/rzaq9/rzaq9osDBSQENativeAccess.htm

-----Original Message-----
From: MIDRANGE-L <midrange-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of Diego Kesselman
Sent: Tuesday, April 30, 2019 9:57 AM
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxxxxxxxx>
Subject: Re: Inconsistent performance

I guess is SQE Native Access

https://www.ibm.com/support/knowledgecenter/en/ssw_ibm_i_72/rzaq9/rzaq9osDBSQEvsCQE.htm

Try setting a QAQQINI on QUSRSYS with SQE_NATIVE_ACCESS =*NO

El mar., 30 de abr. de 2019 08:52, Paul Roy <Paul.Roy@xxxxxx> escribió:

Hello,

Since a few weeks after installing cumpack 18249 at V7R2, we face
inconsistent performance problems...
the same job can take from 3 to 40 minutes in equivalent situation...
the difference from the component report looks in the number of
physical I/O... and the CPU.
job A : 580000 logical I/O ... 222500 Sync I/O ... 117500 Async I/O
perm write 95654 CPU 766 sec (0,29%) duration 25 minutes
job B : 570500 logical I/0 ... 73000 Sync I/O ... 27000 Async
I/O perm write 19051 CPU 8 sec (0,003%) duration 3 minutes

we have 10 jobs started in parallel (each one is handling 1/10 of the
db selected on the last digit of the contract number - the selection
is made with an OPNQRYF ) so the volume and the process in roughly the same in all
jobs. The same process takes 6 CPU sec one day and 600 CPU secs the other
day... this was running smoothly before and the duration is now
unpredictable.

I do not understand what can cause the difference.
What can explain the difference ... same process same number of
logical I/O but much more physical disk I/O...

any suggestion welcome

Thanks

Paul


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