RE: PF with lotsa LFs

["Reeve Fritchman" <reeve@xxxxxxxxxx>]

I have 100 (+/-) access paths over my freight bill (order) header (varying
in size from 100,000 to 2,000,000 records); all except 5 are used for
interactive processing (tracing, lookups, grouping freight bills into
various sequences for auditing, etc).  One LF has 28 formats over two other
PF's as well as the main file; the M$-types don't believe the subsecond
response (even on dog machines) on this monster lookup program.

Some LF's used for batch processing control processing status for certain
time-sensitive jobs where performance is an issue.

I have an LF over the freight bill date; we use that in conjunction with
batch OPNQRYF to select records for reporting or to copy a set of records
into a smaller PF (a daily reporting work file) with zillions of funky
logicals (a byproduct of this technique is that all the reports run on data
isolated from random user changes, and you can rerun the reports any time
under the file is rebuilt).

Overall, I can't imagine a reason I'd create another LF for batch
processing; with the newer machines, OPNQRYF zips through large DB's.  I
don't use embedded SQL or interactive OPNQRYF, and I've never seen a
performance problem.  But make sure you have your database recovery system
value set the wait you want it, and make sure you CHGRCYAP *MIN.  Journal
your PF's, too; it doesn't have anything to do with big LF's but you should
do it if you're not already.

Just my $0.02 USD/$0.03 CAD...

Regards,
Reeve

-----Original Message-----
From: rpg400-l-admin@midrange.com [mailto:rpg400-l-admin@midrange.com]On
Behalf Of Tom Daly
Sent: Friday, February 08, 2002 11:32 AM
To: 'rpg400-l@midrange.com'
Subject: PF with lotsa LFs


Anyone ever have a file with 100+ logicals?

The design choice I'm facing is either fewer LFs but more complicated
inquiry programs & potential performance penalties vs. having many logicals
with simpler and quicker programs (less file reads).

Any wisdom on this?  Pitfalls?  Considerations?


Thanks...

Tom

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