re: Processing efficiency comparisons SQL vs OPNQRYF vs Logical files

Programming --
  Processing efficiency comparisons SQL vs OPNQRYF vs Logical files.


Dwight HoganCamp wrote:
>> If you are running models 7xx or before, you will improve your
>> machines performance drastically by avoiding using SQL in QINTER.

Bill Robins wrote:
>Is this because the Enterprise machines come with full Interactive CPW?  I
>believe even in this instance attention should be considered as to a batch
>job's Run Priority and Timeslice, the amount of memory allocated to the
>subsystem would be a factor as well.

Yes Exactly! For Several models, including ours IBM came up with the CPW
govenor called CFINT01, to monitor interactive jobs access to Disk. It is
triggered, if your CPW usage gets too close to what they designed the model
for. When it sabatages performance, until some time goes by without
CPW being exceeded. If it takes you too long getting it back down, it
requires a call to IBM to get it running right again. CFINT is only visible
from the Ops Navigator. The green screen environment never see it.

>> Performance falls apart when the CWP governor kicks in. We have had
>> enough hassles on our 730, we don't use SQL for anything more than we
>> absolutely have to in QINTER. On our single CPU processor it trashes
>> interactive performance, as it has on many systems I have worked on.
>> Around here the watchword is run all queries in the batch Queue and
>> make as many interactive I-O use LF.

Bill Robins wrote:
>To singularly mention SQL and not OpnQryF is hopefully just an oversight
>because they would impact the system equally.

Our shop was S/3 converted to Wang, converted back to AS/400 and as a result
we don't have many OPNQRYF in this shop, so it hasn't been the same problem
around here, but since it calls QQQQuery, I assume it probably could cause
problems with large files.

Dwight