RE: DSPFD & dates

[Vern Hamberg <vhamberg@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Agreed, Scott. And some logicals may be used only at year end.

In our database/ASSESSMENT (slightly shameless promotion) we analyze unused 
logicals. Our recommendation is to change maintenance to "rebuild" or 
"delay" on rarely used logicals. We don't recommend ever deleting a logical 
unless you are very sure about it.

Also, logicals can be used by the optimizer to determine the lowest cost to 
do a query. These may not get used but help in the decision. Whereas, if 
the optimizer needs to build a temporary index, it will use it, even if the 
query takes longer.

HTH

Vern

At 01:46 PM 6/18/2003 -0700, you wrote:
> Well, one thing I noticed is that running DSPFD will update the
> extract date/time(s) but not the last used :)  I know that
> running a program that uses the file will update the 'last used'
> but I don't know if SQL or OPNQRYF updates this if the logical
> is used as an index to perform a query.  I almost don't think
> they do but this could be tested easily enough.  I would be
> careful deleting logicals that you think aren't used because
> they may be avoiding building indexes on the fly in places.  I
> know this because someone here once was being helpful and
> cleaned up unused logicals, performance of some jobs/programs
> just became terrible.  So be careful :)
>
> Scott Mildenberger