RE: Numerics PACKED, ODD format -- Always recommended?

[Bob Crothers <bcrothers@xxxxxxxxxxxxx>]

Karen,

Yes, it is best (from a performance point of view) to use odd 
length packed numeric data in your files.

However, I don't think I would go back and change stuff just for 
those performance reasons.  I've always believed in "If it Ain't 
broke, don't  fix it".

Yes you are sacrificing a few CPU cycles because of your zoned 
data. But if you are having performance problems, there are 
other areas that would probably be much better to focus on.

And a conversion like you are talking about sounds very 
dangerous.  For very little gain.

BTW, I would start using the Packed number for all new fields 
and files.  I would just leave your existing stuff alone.

Of course, this is just my opinion.

Regards,
Bob Crothers
Cornerstone Communications



-----Original Message-----
From:   Karen Bellecci [SMTP:KBellecci@osfa.state.la.us]
Sent:   Tuesday, March 10, 1998 3:29 PM
To:     MIDRANGE-L@midrange.com
Subject:        Numerics PACKED, ODD format -- Always recommended?

I understand, in defining DDS, the numeric format best suited 
(default) to AS400 is

PACKED, while Zoned requires translation into and out of Packed 
for every usage,
 and
an ODD number of places, whereas an Even number requires 4x as 
many instructions

We have almost completely til now used ZONED numeric, but in the 
interests of performance (doing things right) I would like to 
start using Packed Odd.  I wonder if anyone implements this so 
far as to make all numerics Packed Odd? -- even an 8-digit date 
which we previously used as Zoned 8, and all the 2-digit fields 
we have in a business database.  Are we asking for trouble?

Of course I know we will have to use RUNQRY *NONE to see the 
data now, instead of just Display (#5) on Work with Members 
using PDM screen.  And I suppose there will be overflow warnings 
when these larger fields are moved to some smaller counterpart. 
 But does anyone have a view on this?

Thanks. Karen Bellecci


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