Re: Join Logical File Problem. Venu

If your queries take too long to run because they're busy building access
paths, you may wish to consider the techniques our resident Query expert
uses.

        Lots and lots of intermediate files (as needed) to contain
intermediate results.

        Plus, never, never, never selecting a sort sequence until the last
possible moment,
        when your data's been combined and reduced to the few pieces you
really need.

You zip through your huge files, extracting just the data you need to work
files.  Don't sort!  Just extract.

Once your data's been minimized, you can start recombining it, and, if
small enough, sorting it.

Our expert has taken some nightmares that took 3 or 4 hours to run, and
made 'em run in 3 or 4 -minutes.-    Of course, he understands the data and
its relationships...  (:

--Paul E Musselman
PaulMmn@ix.netcom.com





>Venu,
>                  Ofcourse our files are too big.  As I mentioned "
>Building access path every time when I run OPNQRYF"
>which takes loooong time is our major problem. That is why we thought that
>to replace  Logical File instead of OPNQRYF.
>
>I have never mentioned that I would like to create 3 P.F for this problem.
>What I have mentioned that  is "Open Query is
>joining 3 different P.F ,  and using keyfield, ( Also I have typed the
>exact OPNQRYF command on CL , with dummy
>fille names and filed names  on  my  mail )" .
>
>For the problem of building access path dynamically which takes long time,
>for that I am trying to replace LF   over  OPNQRYF.
>
>Also,  I have mentioned that  " I am struck because joining LF does'nt
>allow me to use secondary file field as a Key field"
>where as  OPNQRYF does'nt have that restriction.
>
>I am very much clear about my problem Venu.
>
>Mr. David Duerr has suggested a solution by using  SQL VIEW.  I am going to
>try that today.
>
>
>- Raj
>
>From: VENU YAMAJALA <venu_yamajala@goodyear.com> AT Internet on 12-21-98
>      04:08 PM
>
>To:   <MIDRANGE-L@midrange.com> AT Internet@ccmail
>cc:    (bcc: Rajan Srinivasan/Servicing/SuperiorBank)
>Subject:  Re: Join Logical File Problem
>
>
>
>
>Hi Raj,
>
>I am not trying to give you an answer to your problem. But it seems you are
>a little confused!! The purpose of OPNQRYF and join logicals is almost
>similar. I normally prefer OPNQRYF if the file is not too big!! If the file
>is too big, I use join logicals. Replacing OPNQRYF with join logicals is
>not always necessary. It depends on the files we use for it.
>
>OPNQRYF generally looks for an exisitng access path. If it finds an access
>path, it uses otherwise, it builds the access path. Building access path
>dynamically is taking long time for you. You can avoid this time by already
>creating the access paths outside. Whether you create 19 different logicals
>or 3 different PFs, is your design issue. But to reduce the time, better
>make OPNQRYF use an existing access path.
>
>Hope this helps.
>
>Vg


+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to MIDRANGE-L@midrange.com.
| To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com.
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---