× The internal search function is temporarily non-functional. The current search engine is no longer viable and we are researching alternatives.
As a stop gap measure, we are using Google's custom search engine service.
If you know of an easy to use, open source, search engine ... please contact support@midrange.com.



Peter,

That's really interesting.....

I'm wondering if there's some problem in your testing procedure.  For
instance, do you always run the 'select' version before the 'omit' version.
Thus the omits gets to take advantage of the data already being in memory. 

I know I've seen some instructions before somewhere on how to do performance
comparisons.  Don't remember any specifics, but it did mention clearing out
memory pools between runs.

HTH,
Charles


> -----Original Message-----
> From: Peter Colpaert [mailto:Peter.Colpaert@xxxxxxxxxxxx]
> Sent: Wednesday, May 12, 2004 5:03 AM
> To: RPG400-L@xxxxxxxxxxxx
> Subject: Difference between Select and Omit in LF
> 
> 
> Hi group,
> 
> has anybody besides me noticed an enormous difference in 
> performance when 
> the following two logical files are read in the exact same 
> RPGLE program - 
> native SETLL and READ, no SQL:
> 
> A          R PSMAST                    PFILE(PSMAST)
> A* 
> A          K PSPACD 
> A          K PSCSNO 
> A          K PSCTNO 
> A* 
> A          S PSATFG                    COMP(EQ 'A') 
> A          S PSSTCD                    COMP(LT '30')
> 
> as opposed to
> 
> A          R PSMAST                    PFILE(PSMAST)
> A* 
> A          K PSPACD 
> A          K PSCSNO 
> A          K PSCTNO 
> A* 
> A          O PSATFG                    COMP(NE 'A') 
> A          O PSSTCD                    COMP(GE '30')
> 
> The 'omit' version seems about 10 times faster.  I haven't 
> actually timed 
> it, but the omit gives subsecond response, whereas the select 
> takes upto 5 
> seconds to retrieve approximately 35 records.
> 
> For what it's worth, the displayed data is of course 
> identical in both 
> versions of the file. I don't even need to recompile the 
> program when I 
> switch LF versions.
> 
> Is this performance difference normal, or am I missing something?
> 
> Thanks,
> 
> Peter Colpaert
> iSeries Application Developer
> 
> Honda Europe NV
> Langerbruggestraat 104
> B-9000 GENT
> Belgium
> Peter.Colpaert@xxxxxxxxxxxx
> Tel: +32 9 2501 334
> Fax: +32 9 2501 231
> ----------
> Real programmers don't document. If it was hard to write, it 
> should be 
> hard to understand.
> ----------
> 
> 
> The information contained in this communication is 
> confidential and may be legally privileged. It is intended 
> solely for the use of the individual or the entity to whom it 
> is addressed and others authorised to receive it. If you have 
> received it by mistake, please let the sender know by e-mail 
> reply and delete it from your system.
> If you are not the intended recipient you are hereby notified 
> that any disclosure, copying, distribution or taking any 
> action in reliance of the contents of this information is 
> strictly prohibited and may be unlawful.
> Honda Europe NV is neither liable for the proper and complete 
> transmission of the information contained in this 
> communication nor for any delay in its receipt.    
> _______________________________________________
> This is the RPG programming on the AS400 / iSeries (RPG400-L) 
> mailing list
> To post a message email: RPG400-L@xxxxxxxxxxxx
> To subscribe, unsubscribe, or change list options,
> visit: http://lists.midrange.com/mailman/listinfo/rpg400-l
> or email: RPG400-L-request@xxxxxxxxxxxx
> Before posting, please take a moment to review the archives
> at http://archive.midrange.com/rpg400-l.
> 

As an Amazon Associate we earn from qualifying purchases.

This thread ...

Follow-Ups:

Follow On AppleNews
Return to Archive home page | Return to MIDRANGE.COM home page

This mailing list archive is Copyright 1997-2024 by midrange.com and David Gibbs as a compilation work. Use of the archive is restricted to research of a business or technical nature. Any other uses are prohibited. Full details are available on our policy page. If you have questions about this, please contact [javascript protected email address].

Operating expenses for this site are earned using the Amazon Associate program and Google Adsense.