Re: Creating Logicals before or after populating a file ?

[Richard Rosenbluth <rose400@xxxxxxxxxxx>]

The performance problem comes from having too many access paths to
maintain (*IMMED) rather than from too many logical files.

When a logical file is created it will implicitly share any existing
access path that has the necessary key structure. If none exists it will
create a new access path.  If you create your logicals from the most
complex key to the most simple, the logicals with the simple key will
share the access path with a logical that has a more complex key with
the same high order key fields.

The implicit sharing will not happen if the logical has a static
select/omit specified because the select/omit with require its own
access path.
 
-- 
Richard Rosenbluth
Rose Information Management Co.
mailto:rose400@pacbell.net
-------------------------------
Bill wrote:
> 
> Isn't there also a run-time performance advantage
> to building logicals in an order that is based on
> the keys involved?  Something about shared
> indexes?
> 
> I've been practicing this but don't recall the
> reason, stinking aging problem again!
> 
> Bill.
>
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