If you only want the last 2,000 records or so, why not just close the file and
reopen it every 3,000 or so records?
Bill
> Date: Mon, 28 Jan 2008 15:41:03 +0100> From: [EMAIL PROTECTED]> Subject: Re:
> Keep only the tail of the dataset> To: [email protected]> > Hi> > I mean
> the program is ready and working , so no program > modification, and it shoud
> happen "in flight"> For example keep only the last part of the trace.> >
> McKown, John wrote:> > >>-----Original Message-----> >>From: IBM Mainframe
> Discussion List > >>[mailto:[EMAIL PROTECTED] On Behalf Of Miklos Szigetvari>
> >>Sent: Monday, January 28, 2008 2:10 AM> >>To: [email protected]>
> >>Subject: Keep only the tail of the dataset> >>> >>> >> Hi> >>> >> Searching
> for a method to keep/access only the tail of a dataset.> >> An application
> writes internal traces , several million > >>lines. I would > >>like to keep
> only the last part of the trace.> >>Any simple method to achive this ?>
> >>(Currently I can think to pipe under USS , and write a small > >>program to
> > >>wrap around )> >>> >>-- > >>Miklos Szigetvari> >> > >>> >> >If you want a
> "wrap around" type log, then I think that the easiest way> >to do so would be
> to have a preformatted BDAM or VSAM RRDS dataset. I'd> >personally go with
> the RRDS. Have the first record be dedicated to> >keeping the "next" record
> number to write. Also, have the maximum record> >number in there. Now have
> your subroutine simply increment the record> >number and wrap around from the
> max to 1 (skipping 0). You could either> >update record 0 upon every write
> (high overhead) or only periodically. I> >would also keep a timestamp in
> every record so that you could use SORT> >to put the records in order. This
> is about as simple as I can think of> >off-hand.> >> >--> >John McKown>
> >Senior Systems Programmer> >HealthMarkets> >Keeping the Promise of
> Affordable Coverage> >Administrative Services Group> >Information Technology>
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