RE: Embedded SQL Logical file use

Jim,

Thanks for the info.

As I recall, when I started on the 400, IBM was recommending that
logicals be specified.

Then at some point, that changed.

>From what you're saying, the recommendation now is try it.<grin>

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

> -----Original Message-----
> From: rpg400-l-bounces@xxxxxxxxxxxx 
> [mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Jim Franz
> Sent: Friday, March 31, 2006 10:06 AM
> To: RPG programming on the AS400 / iSeries
> Subject: Re: Embedded SQL Logical file use
> 
> I spoke to the DB2 developers at Common on this specific question.
> The use of a logical file in a select in a sqlrpgle will 
> cause the "classic"
> sql optimizer to evaluate that logical first, but the 
> optimizer may or may 
> not select that view.
> I have been able to demonstrate at v5r3 that in one instance, 
> using the 
> logical  in a select
> did greatly boost performance. Logical did not have 
> select/omit criteria.
> Check the use of the QAQQINI  query options to see if 
> anything fits your 
> needs. I have
> not explored this, but it was a recommendation from the developers.
> 
> For another thread - some very interesting new performance 
> features in 
> v5r4....
> 
> Jim Franz
> 
> 
> ----- Original Message ----- 
> From: "Mark Allen" <scprideandms@xxxxxxxxx>
> To: "RPG programming on the AS400 / iSeries" <rpg400-l@xxxxxxxxxxxx>
> Sent: Thursday, March 30, 2006 8:27 AM
> Subject: Re: Embedded SQL Logical file use
> 
> 
> > check the archives , seems there weas a discussion while 
> back on a setting
> > for the Optimizer to "fix" this?
> >
> > On 3/29/06, Kyle Collie <kcollie@xxxxxxxxx> wrote:
> >>
> >> We have an SQLRPG module that is opening a cursor based on a S/O
> >> logical. Everytime the program is run the query optimizer 
> is checking
> >> for a better file to use and is eventually just coming 
> back and using
> >> the initial S/O logical that we specified in the select 
> statement. Is
> >> there a way to force the logical and prevent that 
> processing time that
> >> is wasted when it tries to find a better index?
> >>
> >> The time it takes up is about 1 minute 20 seconds.
> >>
> >> Thanks in advance,
> >>
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