Thanks to everyone for replying to this. I am definitely going to get
the apps guys to change the JCL. I just haven't whether it would be to
change it to a sort, or create a second dataset. Will read the
recommendations between the lines of the DFSORT manual...

Regards

Herbie


-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On
Behalf Of Frank Yaeger
Sent: 22 Januarie 2008 03:50 nm
To: [email protected]
Subject: Re: DFSORT anomaly?

David Betten wrote on 01/22/2008 06:53:52 AM:
> I haven't seen any job output yet but I wanted to share this
information
> from DFSORT Application Programming Guide
>
> ***
> For a copy application, the SORTIN data set should not be the same as
the
> SORTOUT data set or any OUTFIL data set because this can cause lost or
> incorrect data or unpredictable results.
> ***
>
> Frank probably knows more about this but it makes sense to me why we
could
> have problems for COPY.  When we do a SORT, all of the records from
SORTIN
> need to be read before we can write anything to SORTOUT.  This is
because
> that last record read could potentially be the first record written.
> However, when we do a COPY, we can start writing to SORTOUT
immediately.
> I would just try changing your sort step to write a new dataset and
see
> what the results are.

Dave has it right.  I just got here and was going to write a similar
post.
You SHOULD NOT use the same data set for SORTIN and SORTOUT for a COPY
for
the reason Dave states that we are doing parallel read/write.  Depending
on
how the data is arranged, you may get away with it, but you're taking a
risk.
We can't guarantee that you won't lose records.  So just don't do it.

You can use the same data set for SORTIN and SORTOUT for a SORT because
we
don't do parallel read/write.  This is commonly known as a "suicide
sort"
because the "input" data set is overwritten so if something goes wrong
(e.g. an I/O error) you don't have the input data set anymore.  So you
would want to be sure you have a backup for the input data set if you do
a suicide sort.

Frank Yaeger - DFSORT Development Team (IBM) - [EMAIL PROTECTED]
Specialties: PARSE, JFY, SQZ, ICETOOL, IFTHEN, OVERLAY, Symbols,
Migration

 => DFSORT/MVS is on the Web at http://www.ibm.com/storage/dfsort/

----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
Elavon Financial Services Limited
Registered in Ireland: Number 418442
Registered Office: Block E, 1st Floor, Cherrywood Business Park, Loughlinstown, 
Co. Dublin, Ireland
Directors: Robert Abele (USA), John Collins,  Terrance Dolan (USA),  Pamela 
Joseph (USA), Declan Lynch, John McNally, Malcolm Towlson
Elavon Financial Services Limited, trading as Elavon, is regulated by the 
Financial Regulator

----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html

Reply via email to