Re: PF with lotsa LFs

[rob@xxxxxxxxx]

Let me retype this again:

>From the November 1998, Volume 1, Number 1 copy of AS/400 Experts Journal,
in an article by Skip Marchesani:

Access Paths are a Good Thing!
There is a myth in the AS/400 community that is no longer true.  That is:
Access paths (logical files) on a file are resource intensive, have a
negative impact on performance, and should only be used where absolutely
necessary.

This is no longer true in today's environment on the AS/400!
This myth stems from the S/38 and was the guideline that IBM was giving
customers at that time.  The Rochester development lab began to change the
algorithms for access path maintenance in Version 2 of OS/400 and finished
the task in V3R1.  Access paths (logical files) are no longer the
resource/performance hog they used to be on the S/38.

In today's environment of decision support, data warehouse, and
client/server applications queries are a fact of life.  It is perfectly
acceptable to build an access path on a file to optimize query performance.
So if someone tells you it's bad design to have access paths on a file for
query optimization, tell them to get out of the dark ages and get into the
21st century.


Rob Berendt
--
"They that can give up essential liberty to obtain a little temporary
safety deserve neither liberty nor safety."
Benjamin Franklin



                    Tom Daly
                    <Tdaly@sddsystems       To:     "'rpg400-l@midrange.com'" 
<rpg400-l@midrange.com>
                    .com>                   cc:
                    Sent by:                Fax to:
                    rpg400-l-admin@mi       Subject:     PF with lotsa LFs
                    drange.com


                    02/08/2002 11:31
                    AM
                    Please respond to
                    rpg400-l






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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