Re: System 38 PF and LF

[Dave Shaw <dshaw1@xxxxxxxxxxx>]

-----Original Message-----
From: Henrik Krebs <Henrik.Krebs@Scout.Net>
To: MIDRANGE-L@midrange.com <MIDRANGE-L@midrange.com>
Date: Wednesday, June 10, 1998 6:35 PM
Subject: Sv: System 38 PF and LF


>Dave Shaw <dshaw1@InfoAve.Net> wrote
>
>
>> Also, I believe that S/38 logicals default to FIFO order for
>> records with duplicate keys, whereas the AS/400 default is
>> essentially an indeterminate order (this broadens the opportunities
>> for sharing of access paths).
>
>No.
>The 'official answer' was 'unpredictable'. In practice I've seen *ARRIVAL
>only. So I guess, that there is no difference between PF and PF38's for
>that matter.

I don't remember if there's a difference in PF's.  I don't believe there was
anything significant, although I'm not sure if the 1-TB max access path size
is supported o PF38's.  I was specifically discussing LF's.  Is there a
difference in meaning between "indeterminate" and "unpredictable" in this
context?

A specific example of where the difference in LF behavior occurs is if you
have an LF defined with two key fields, and then create another LF with one
key field the same as the first key field of the first LF.  S/38 will
default to FIFO (*ARRIVAL) sequence for the duplicate keys and build a new
access path for the second LF, AS/400 will default to sharing the access
path created for the first LF and not create a second one.

Dave Shaw, General Nutrition, Greenville, SC (just down the road from BMW -
Bubba Makes Wheels :)
The opinions expressed may not be my employer's unless I'm sufficiently
persuasive...


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