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Performance Issue

PostPosted: Thu Jul 15, 2010 7:54 pm
by gali prasad
Dear all,

My application has below SORT utility in JCL and basically SORT is used here to copy large data from large VSAM file to a flat file as a backup purpose

//S010 EXEC PGM=SORT
//SORTIN DD DSN=Large vsam file,DISP=SHR,
// AMP=(AMORG,'BUFND=20')
//SORTOUT DD DSN=flat file,
// DISP=(NEW,CATLG,DELETE),
// UNIT=CART,LABEL=EXPDT=99000,VOL=(,,,99),
// DCB=PRD.T.LRECL150
//*
//SYSIN DD DSN
SORT FIELDS=COPY

Above process is nearly taking more time to run and please suggest me if any improvements can be done or else any utility that can replace above.

Thankyou very much,
Prasadg

Re: Performance Issue

PostPosted: Thu Jul 15, 2010 10:43 pm
by NicC
IDCAMS REPRO - it was invented for working with VSAM files
ADRDSSU - it was invented for taking backups

Re: Performance Issue

PostPosted: Thu Jul 15, 2010 11:57 pm
by Robert Sample
Why do people have trouble providing necessary details? For example, we back up 2 VSAM files totaling 37,000 cylinders (11 mod 3 disk packs or about 30 gigabytes) in 43 minutes using ADRDSSU -- going to tape. That gives you size and time values for comparison purposes -- details that are needed by responders!

How big is a "large" VSAM file to you? How much time is the SORT step taking?

Re: Performance Issue

PostPosted: Fri Jul 16, 2010 11:35 am
by gali prasad
Hello Robert,

I will check jobs and will let you know information.

Thanks for your response.

Re: Performance Issue

PostPosted: Sat Jul 17, 2010 12:42 am
by Bill Dennis
Also, are the output tapes real or virtual? What media type? 3490, 3590, 3592?

Re: Performance Issue

PostPosted: Mon Jul 19, 2010 11:23 am
by gali prasad
Dear Robert,

The VSAM file has around 3240860 records and its consuming time of nearly one minute.

Please let me know if any advice.

Thankyou.

Re: Performance Issue

PostPosted: Mon Jul 19, 2010 12:55 pm
by dick scherrer
Hello,

Why do you believe 1 minute is too much?

Re: Performance Issue

PostPosted: Mon Jul 19, 2010 2:36 pm
by gali prasad
Dear Dick,

The job runs nearly for 2 minutes in some cases, based on size of file and I want to know if there is any suggestion that can improve my performance if my input VSAM file crosses 100 millions.

Hope you understand my issue.

Thankyou very much,

Re: Performance Issue

PostPosted: Mon Jul 19, 2010 3:33 pm
by NicC
2 MINUTES! For 3 MILLION records? I would start thinking about other methods if it approaches 30-45 minutes. You will be retired by then!

Re: Performance Issue

PostPosted: Mon Jul 19, 2010 5:06 pm
by Robert Sample
Please tell me you are kidding us about being worried about performance. If you are backing up 100 million records, one hour elapsed time is not by any means unusual or out of line. If you want to reduce this time, you will have to work with your site support group to schedule the job to run when the system workload is at a minimum; nothing else will help you.