Re: %lookup vs. chain

["Booth Martin" <Booth@xxxxxxxxxxxx>]

This step is unclear to me.  The control file has a key? That key is in each
of the million-plus records? How often will the value of the Control File
Key change?  I understand that the changes may occur randomly but if the
control file has a relativly lower record count then many of the chains
might be going for the same record just returned.

Is it possible that the greater gain might be to save the Contol File Key,
and only chain if the Control File Key is different?

---------------------------------------------------------
Booth Martin   http://www.MartinVT.com
Booth@MartinVT.com
---------------------------------------------------------

-------Original Message-------

From: midrange-l@midrange.com
Date: Friday, November 22, 2002 09:08:58 AM
To: 'midrange-l@midrange.com'
Subject: %lookup vs. chain

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I'm just noticing that as I spin through some large files that I'm chaining
out a million times (actually more) to a control file to check a flag. In
the initial subroutine I'm setting up an array that I could easily store
this flag in. I'm wondering what the opinion is as far as performance-wise
which is more efficient, doing the %lookup() on the array or chain to the
file?

Thanks in advance.

Mike
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