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November 2001, Week 1

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Subject:
Re: COBOL
From:
"Shahan, Ray" <[log in to unmask]>
Reply To:
Shahan, Ray
Date:
Thu, 1 Nov 2001 13:50:30 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (59 lines) 
Mark Berkowitz writes:


        "Secondly, for real performance on a large array, assuming it is
already
        filled and is just being searched, try using the "SEARCH ALL" format
of
        SEARCH.  This binary search will seriously speed up searches.  A
table of
        5000 entries that is binary searched will only have to check at most
13"


Mark, FYI (I assume you already know this), the array must also be sorted to
do this, and of course, you must have an INDEXED BY clause.


> -----Original Message-----
> From: Michael Berkowitz [SMTP:[log in to unmask]]
> Sent: Thursday, November 01, 2001 1:12 PM
> To:   [log in to unmask]
> Subject:      Re: COBOL
>
> Shawn Gordon writes
>
>
> There is a very small difference, I did some performance tests years
> ago, but I got in the habit of using the INDEXED BY because of some of
> the convenient features of it, however some of the problems are that you
> can't display the index so there are situations where it is bothersome.
>
> On Thursday, November 1, 2001, at 10:55 AM, Shahan, Ray wrote:
>
> > Hey all,
> >
> > Does anyone know if there is any performance diff gained by using
> > INDEXED BY
> > over using a separate field as an index while accessing very large
> > arrays?
> -------------------------------------------------------
> Couple of things.  First you can display the index.  This enhancement was
> added in 5.5 along with secondary entry points, call by plabel, etc.  In
> fact I think Shawn actually commented on these in an Interact article.
>
> Secondly, for real performance on a large array, assuming it is already
> filled and is just being searched, try using the "SEARCH ALL" format of
> SEARCH.  This binary search will seriously speed up searches.  A table of
> 5000 entries that is binary searched will only have to check at most 13
> entries before it has a hit.
>
> Mike Berkowitz
> Guess? Inc.
>
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