Why the prioriy changes automatically when the job runs for

vinodmohrir · New User Joined: 07 Nov 2009 Posts: 1 Location: india

Is the priority changes automatically when the job runs for long time?

Robert Sample · Posted: Fri Nov 13, 2009 2:15 am

The site support group can implement WLM rules and exits to control what happens to long-running jobs.

MBabu · Posted: Fri Nov 13, 2009 2:37 am

The reason is that TSO is intended for short transactions like pressing the enter key go see a new screen, editor changes, and that sort of thing. Some sites do longer tasks like compiles in TSO but even then they are fairly short. The idea is that if you are going to run long running jobs that do not require sub second response time, those workloads are similar to batch and most sites define performance rules accordingly. Long running TSO transactions tend to get lower priority.

Robert Sample · Posted: Fri Nov 13, 2009 4:09 am

MBabu, I have to comment that your entire post is about TSO whereas the T/S just mentioned "job" -- which could be started task, submitted batch job, TSO address space, or even OMVS process depending upon the precise definition being used for "job". WLM does allow for multiple levels of responsiveness for batch jobs just as with TSO sessions. And I have been at shops that used system exits to lower priority of executing batch jobs if they exceeded certain parameters. Without a better definition from the T/S about what is being called a "job", it is probably misleading to refer to nothing but TSO.

Pedro · Posted: Fri Nov 13, 2009 5:26 am

At our site, some long running batch jobs are held back during the day and run at night. The preference during the day is for TSO users. I think some long running batch jobs are slowed down so they do not compete for resources against TSO users.

As Robert said, it is a setting that the support personnel set.