Portal | Manuals | References | Downloads | Info | Programs | JCLs | Master the Mainframes
IBM Mainframe Computers Forums Index
 
Register
 
IBM Mainframe Computers Forums Index Mainframe: Search IBM Mainframe Forum: FAQ Memberlist Usergroups Profile Log in to check your private messages Log in
 

 

VSAM file to be used by more than 1000 jobs in a day

 
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM
View previous topic :: :: View next topic  
Author Message
i.jagath

New User


Joined: 21 May 2010
Posts: 3
Location: USA

PostPosted: Thu Aug 20, 2015 10:36 pm    Post subject: VSAM file to be used by more than 1000 jobs in a day
Reply with quote

Please suggest which is the best way to make a VSAM file available for read/update by 1000 jobs. All these jobs run daily and are file triggered. Files are copied into the mainframe at 5 min intervals from a FTP server i.e. there is a huge possibility that 10 files arrive on mainframe and 10 jobs get triggered and they are trying to get exclusive access of the VSAM.

The problem that we are facing with one approach i.e. if we used DISP=SHR and share options 3, there is an issue with sequence integrity and also one job gets hold of the vsam and other jobs abend.

Any recommendation on what should be the approach best suited for our needs.
Back to top
View user's profile Send private message

RahulG31

Active User


Joined: 20 Dec 2014
Posts: 331
Location: USA

PostPosted: Thu Aug 20, 2015 11:45 pm    Post subject: Reply to: VSAM file to be used by more than 1000 jobs in a day
Reply with quote

Are all the jobs update jobs?

And how long is each job supposed to run? Can they finish in 5-10 mins or they may take hours to complete?

Can you have 10 separate VSAM files created from the original and merge them later?

I think the important question is how many jobs are going to update the VSAM and how many are read only.
Back to top
View user's profile Send private message
i.jagath

New User


Joined: 21 May 2010
Posts: 3
Location: USA

PostPosted: Thu Aug 20, 2015 11:50 pm    Post subject: Reply to: VSAM file to be used by more than 1000 jobs in a day
Reply with quote

All the jobs does the same thing read and update the VSAM.

Most of the jobs will run in less than 5 min but some jobs take upto 2 hours.
Back to top
View user's profile Send private message
RahulG31

Active User


Joined: 20 Dec 2014
Posts: 331
Location: USA

PostPosted: Thu Aug 20, 2015 11:57 pm    Post subject: Reply to: VSAM file to be used by more than 1000 jobs in a day
Reply with quote

And can you divide the VSAM into, say 10 parts, and use each part in approx. 100 jobs which use those particular records. Is it a possibility?

Secondly, do you have anything such as update timestamp in VSAM?
Back to top
View user's profile Send private message
i.jagath

New User


Joined: 21 May 2010
Posts: 3
Location: USA

PostPosted: Fri Aug 21, 2015 12:37 am    Post subject: Reply to: VSAM file to be used by more than 1000 jobs in a day
Reply with quote

splitting the VSAM is not a possiblity. We are in code freeze for our project and this change will not be approved. I am looking at smaller approach.

and there is no update timestamp.
Back to top
View user's profile Send private message
Rohit Umarjikar

Senior Member


Joined: 21 Sep 2010
Posts: 1610
Location: NY,USA

PostPosted: Fri Aug 21, 2015 1:49 am    Post subject:
Reply with quote

Quote:
i.e. if we used DISP=SHR and share options 3, there is an issue with sequence integrity


What do you mean by this?

Quote:
and also one job gets hold of the vsam and other jobs abend.


Try for Negative dependency between the jobs during the scheduling?
Back to top
View user's profile Send private message
Nic Clouston

Global Moderator


Joined: 10 May 2007
Posts: 1715
Location: UK

PostPosted: Fri Aug 21, 2015 2:29 am    Post subject:
Reply with quote

You could make all the jobs run in the same class - and allow no other jobs to run in that class. Then set the machine up so that there is only one initiator processing that class.
Back to top
View user's profile Send private message
dneufarth

Active User


Joined: 27 Apr 2005
Posts: 236
Location: Cincinnati OH USA

PostPosted: Fri Aug 21, 2015 7:36 am    Post subject:
Reply with quote

Nic,

You would think that a "serial" initiator would be standard in all shops just for things like this. Guess it was the norm in the past, but not anymore.

Dave
Back to top
View user's profile Send private message
Terry Heinze

JCL Moderator


Joined: 14 Jul 2008
Posts: 1238
Location: Richfield, MN, USA

PostPosted: Fri Aug 21, 2015 7:50 pm    Post subject:
Reply with quote

Record Level Sharing (RLS) could be PART of the solution. Are you using it?
Back to top
View user's profile Send private message
David Robinson

Active User


Joined: 21 Dec 2011
Posts: 175
Location: UK

PostPosted: Tue Aug 25, 2015 1:36 pm    Post subject: Reply to: VSAM file to be used by more than 1000 jobs in a day
Reply with quote

Surely the easiest way is just to use your scheduler to ensure only one job can run at a time?
Back to top
View user's profile Send private message
Garry Carroll

Active Member


Joined: 08 May 2006
Posts: 990
Location: Dublin, Ireland / Edinburgh, Scotland

PostPosted: Tue Aug 25, 2015 3:34 pm    Post subject:
Reply with quote

If the jobs can run concurrently and require update access, maybe consider using the CICS EXCI interface to have CICS perform the I/O and ensure datga integrity?

Garry.
Back to top
View user's profile Send private message
Pete Wilson

Active User


Joined: 31 Dec 2009
Posts: 437
Location: London

PostPosted: Tue Sep 08, 2015 2:42 am    Post subject:
Reply with quote

You could explore the use of VSAM Record Level Sharing (RLS) for the file.

It involves a possible new Storclas definition and possible Coupling Facility structure definition.

(damn..just saw Terry already suggested!)
Back to top
View user's profile Send private message
View previous topic :: :: View next topic  
Post new topic   Reply to topic    IBMMAINFRAMES.com Support Forums -> JCL & VSAM All times are GMT + 6 Hours
Page 1 of 1

 

Search our Forum:

Similar Topics
Topic Author Forum Replies Posted
No new posts Add PD field from 2nd file to PD in 1st Sushant Garje DFSORT/ICETOOL 6 Thu Dec 01, 2016 4:32 pm
No new posts File Aid to File Manager conversion murali3955 IBM Tools 4 Thu Nov 24, 2016 3:41 pm
No new posts How to convert the VBM file to VB or... Sulabh Agrawal JCL & VSAM 4 Fri Nov 18, 2016 1:04 pm
No new posts CICS Roll back partially - Need to re... dwijadas CICS 4 Wed Nov 16, 2016 4:30 pm
No new posts Problem in writing Output file vickey_dw COBOL Programming 5 Mon Nov 14, 2016 11:14 pm


Facebook
Back to Top
 
Mainframe Wiki | Forum Rules | Bookmarks | Subscriptions | FAQ | Tutorials | Contact Us