Linking to a subfile (was Subphyla question)

Merol Newman meroln@specialist.co.uk
Thu, 2 Mar 2000 10:48:24 -0000


Hello Matt

I only joined yesterday, and I don't think I'll have time to read anything most
days, let alone reply! And little did I think I would have anything useful to
say - I joined to pick other people's brains. But somewhere in the flood of
messages I think one programmer said his report took 45 minutes to link to
record 1 of the subfile on Unix. Could it be because Unix can't find record 1,
and so doesn't use the buffer as described?

It should be:-      record 1 on Vax VMS
                    record 0 on HP MPE (HP3000, HP/XL)
                    record 0 on Unix

I've been using this method for years, including at various times all three
platforms, and never found any performance problems.
 
Merol Newman
E-mail: meroln@specialist.co.uk <mailto:meroln@specialist.co.uk>

I've just found the relevant bit:-

 G'day Matt
>
> I have to challenge you on what you said about "Quiz will read the
> subfile
> record once".  I 'fixed' a report for a client last year on a
> HP/UX box
> where a report was taking 45 minutes to run.  This report was
> reading a
> table and linking to record 1 of a subfile.  It read the subfile for
> each
> occrrence on the primary file.
>
> I replaced the logic using an environment variable and a CHOOSE on the
> primary file instead.  This reduced the run time to only 5 minutes.
>
> Blue


> >
> > Actually you can link to the subfile from your data file. Try this:
> >
> > ACCESS datafile LINK TO RECORD 1 OF *subfile
> >
> > SELECT IF dateitem of subfile = dateitem of datafile
> >
> > Quiz will read the subfile record once and keep it in memory
> > through the
> > entire run, so it should be quite effecient.
> >
> > You didn't say what machine you are on, but the above works
> > for VAX and
> > UNIX
> > (I believe). If you are on an HP3000, substitute a zero for the "1" in
> > the
> > ACCESS statement.
> >
> > Matt
> >


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