RE: Usage of Indexes and its Effects on an RPG Program

Nope not a bug, read through the archives for the RPG list and you'll
see more info but basically READE can't take advantage of record
blocking the way READ can.

On the flip side, READE always compares keys correctly, whereas READ +
your own compare routine will not.  For instance if you have a case
insensitive sort field, or some other alternative sorting sequence.

But Scott Klement pointed out that since the OP is updating every
record, READ wouldn't be able to use record blocking anyway.  So for the
OP in this instance, READP and READ would perform the same.


HTH,

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121
  

> -----Original Message-----
> From: midrange-l-bounces@xxxxxxxxxxxx 
> [mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Rich Duzenbury
> Sent: Wednesday, December 14, 2005 12:58 PM
> To: Midrange Systems Technical Discussion
> Subject: RE: Usage of Indexes and its Effects on an RPG Program
> 
> 
> > On a wider note, it sounds like you are trying to improve 
> performance.
> > I've been preaching here a couple times in the last few 
> weeks about the
> > hazards of using READE over a large data set, since it 
> doesn't read from
> > a block of records in memory, but actually hits the file 
> for every read.
> 
> It sounds like you are describing a bug.  I can't think of a single
> reason why READE should not perform nearly as well as READ, other than
> the overhead of the key comparisons.  
> 
> How badly does it perform, in comparison to a READ? 
> 
> If it's not been implemented properly by IBM than we should file a bug
> report.  Has anyone filed a PMR on this matter?
> 
> Regards,
> Rich
> 
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