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rsantosh · Beginner Joined: 20 Dec 2014 Posts: 44 Topics: 10

Hello, I have a JCL which has 1st step as wait of 5 minutes. In the next step it reads a file. When I run the job and try to create the same file when the job is in wait period of 5 minutes and next step has not started executing, I sill get dataset contention. Does the job locks the dataset even though the step where it is used has not started executing?
Step01 makes the job wait for 5 minutes. While job is in wait status (STEP02 hasn't started yet) i tried to create HLQ.TEST but received contention. We have JES2. Will I get same issue with JES3?

kolusu · Posted: Thu Oct 16, 2025 10:49 pm Post subject:

rsantosh,

DISP=SHR will NOT cause an exclusive lock. Some other job/user is holding the job. When you received contention message , issue the command shown below and press enter. It will show the EXCLUSIVE lock in RED

rsantosh · Beginner Joined: 20 Dec 2014 Posts: 44 Topics: 10

I submitted the job and while it was in wait status, I issues the ddlist e command. The job didn't have exclusive lock on HLQ.TEST but when I tried to create the dataset with 3.2 I received below message, the jobname shown by the message is the same job which I submitted and was in wait step.

rsantosh · Beginner Joined: 20 Dec 2014 Posts: 44 Topics: 10

Just to add the job ended with JCL error because the data set HLQ.TEST was not found. Due to contention I couldn't create the data set Regards, Santosh
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Regards, Santosh

kolusu · Posted: Fri Oct 17, 2025 11:00 pm Post subject:

rsantosh,

Is your system part of sysplex ? If so you need to ensure that the dataset is NOT shared across systems. Assuming you have authorization for /D XCF command from SDSF and it will show you names.
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rsantosh · Beginner Joined: 20 Dec 2014 Posts: 44 Topics: 10

Hello Kolusu, I checked, the LPAR is part of sysplex. How can I check if dataset is not shared across systems? If it is shared, will SHR not work the way it is supposed to work?
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Regards, Santosh

kolusu · Posted: Mon Oct 20, 2025 11:00 pm Post subject:

rsantosh,

If an LPAR is holding the dataset exclusively , then it means someone coded DISP=OLD or they creating the dataset and the task is still running. So you need to find out the job/task that is issuing the exclusive lock.

Search for the dataset name across the proclib/JCL libraries.
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rsantosh · Beginner Joined: 20 Dec 2014 Posts: 44 Topics: 10

Hello Kolusu, There is no other task/job holding the dataset I coded. I am not using any generic dataset name. For testing purpose I used my TSO ID only so that no one else can use it.
Instead of 3.2, I submitted below job in order and 2nd job showed the error message.
Job # 1

kolusu · Posted: Sat Oct 25, 2025 8:04 am Post subject:

rsantosh,

Does the dataset already exist? If so looks like zeke is creating the EXCLUSIVE ENQ on the dataset even though it has DISP=SHR.

I am not sure wait 300 is in seconds or minutes. Assuming wait is in seconds and the job-1 is in a wait/suspended state for 5 mins , job-2 should be able to run and create the dataset. If it is NOT then you need to check if zeke is creating the exclusive locks
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rsantosh · Beginner Joined: 20 Dec 2014 Posts: 44 Topics: 10

kolusu · Posted: Mon Oct 27, 2025 9:33 am Post subject:

rsantosh,

Since the dataset does NOT exist, Job1 created an ENQ on the dataset name as soon as it starts executing, even thought the first step is a wait.

The 2nd job is in a wait state as it needs to create the dataset and update the catalog with the information. It is here that job2 will be waiting for the exclusive lock and hence the wait.

Once the wait is cleared, JOB1 will end with a JCL error as the dataset does NOT exist.

BTW what exactly are you trying to achieve here ? May be depending on the requirement, there might be an alternative.
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