Re: Query Performance

[Chuck Lewis <clewis@xxxxxxxxxx>]

Another question on query...

When you "Specify file selection" in query this IS (or isn't) the order in which
the files are processed ? I.E. the first file in the list is the "primary" file,
etc. ?

Thanks !

Chuck

James W Kilgore wrote:

> Chuck,
>
> AFAIK, even if you do use logicals, there's no guarantee that Query will
> use it.
>
> I think I've also read on this list that Query looks at a few of your
> logicals, not all of them, before it just goes ahead and builds one.
>
> Now the above seems to hold true if you are constantly changing your
> record selection.
>
> For more static queries, we STRDBG, change our logging level, run the
> query then check the job log.
> It makes logical file recommendations.
>
> HTH
>
> Chuck Lewis wrote:
> >
> > Hi Folks !
> >
> > We've got "novice" query users creating queries over a 3rd party
> > applications' data base. They do a fairly good job in selection logic
> > but have no real knowledge of Logical Files so they are using Physical
> > Files which are NOT keyed so I am REALLY questioning the efficiency of
> > some of these queries.
> >
> > I know there is something called the "Predictive Query Governor" - is
> > any using this or have you and is it helpful in the above scenario for
> > "ratting out" problems ?
> >
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