RE: Efficient Code -- RPG400-L

>Well, DBU has DBUDBR, or F14 from the main DBU screen.

Nope. DBU shows you logicals, not indexes. Access path sharing causes these
to be different. DSPDBR is the same. 

DSPFD *ACCPTH is close, but as I just showed, an access path can have more
keys than it's owning logical file.

AFAIK, there is no display of the actual _access paths_ built over a
physical.

-Walden 


------------
Walden H Leverich III
President & CEO
Tech Software
(516) 627-3800 x11
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Quiquid latine dictum sit altum viditur.
(Whatever is said in Latin seems profound.)
 
-----Original Message-----
From: G Armour [mailto:garmour400r@xxxxxxxxx] 
Sent: Wednesday, February 18, 2004 11:53 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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