RE: Efficient Code

[<Rick.Chevalier@xxxxxxxxxxxxxxx>]

I haven't been following this real close so I apologize if this is redundant.

The OS/400 command DSPDBR (Display database relations) will show the logical 
files build over a given physical.  Doesn't provide any information other than 
the name though.

Rick

> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx]On Behalf Of G Armour
> Sent: Wednesday, February 18, 2004 10:53 AM
> To: RPG programming on the AS400 / iSeries
> Subject: RE: Efficient Code
> 
> 
> > I wonder if there is a way to see the indexes on a system.
> 
> Well, DBU has DBUDBR, or F14 from the main DBU screen.
> 
> On systems without DBU, you have to build your own using 
> DSPDBR & DSPFD *ACCPTH &
> *SELECT.
> 
> IIRC, iSeries Navigator has something related to this.  I'm 
> too low on memory to
> check it out at the moment.  
> 
> What is *really* needed, IMO, is a report you can run to 
> identify the logicals that
> can be "rebuilt" to take advantage of access path sharing.  
> Plug in a physical file
> name, get back a listing of logicals that can be optimized like this.
> 
> If someone has already created the wheel....   <g>
> 
> GA
> 
> --- "Walden H. Leverich III" <WaldenL@xxxxxxxxxxxxxxx> wrote:
> > Nope, just double checked on V5R2. If you create them in 
> the wrong order (A,
> > A+B, A+B+C) there is no sharing. 
> > 
> > Keep in mind too, you don't need to recreate the logical, 
> just the index, so
> > a RMVM/ADDLFM works.
> > 
> > Given:
> > LF_A - Keyed Field1
> > LF_B - Keyed Field1, Field2
> > LF_C - Keyed Field1, Field2, Field3
> > 
> > If you create them in the wrong order (LF_A then _B then 
> _C) LF_A owns
> > index_A and LF_B owns index_B and LF_C owns index_C.
> > 
> > If you then you RMVM/ADDLFM on LF_B it will share the index 
> from LF_C -
> > makes sense.
> > 
> > Additionally, if you then delete LF_C the index ownership 
> will revert to
> > LF_B. So far so good. 
> > 
> > If you then recreate LF_C it will share the index in LF_B. 
> So, when the
> > index moved from LF_C to LF_B when you deleted _C it 
> retained it's full key
> > structure even though it was owned by a LF that didn't need 
> the structure. 
> > 
> > I wonder if there is a way to see the indexes on a system.
> > 
> > Also, remember FIFO, LIFO, FCFO are all considered "keys", 
> to get sharing
> > you need to leave the ordering unspecified.
> > 
> > -Walden
> 
> 
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