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Browse contents of an active dataset?

 
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mogens
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PostPosted: Tue Oct 10, 2006 6:36 am    Post subject: Browse contents of an active dataset? Reply with quote

I have allocated a sequential dataset with DISP=SHR because I want to be able to browse the contents while my long running job is writing into it. But entering b(rowse) to this dataset in ISPF 3.4 fails with
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kolusu
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PostPosted: Tue Oct 10, 2006 8:45 am    Post subject: Reply with quote

mogens,

Your job hasn't started writting to the dataset. The allocation you see is initial allocation of the dataset when the dsn is first opened.

Kolusu
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semigeezer
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PostPosted: Tue Oct 10, 2006 6:58 pm    Post subject: Reply with quote

the dscb isn't rewritten until the data set is closed (or maybe goes into extents)
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mogens
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PostPosted: Wed Oct 11, 2006 2:29 am    Post subject: Reply with quote

Thankyou for your input.

To kolusu's answer:

Quote:

Your job hasn't started writting to the dataset.


Sorry, but this is not true. It is a newly allocated dataset that started out with allocated tracks and allocated extents of 1. And I can these two figures increase while my job is running.

To semiqeezer's answer:

Quote:

(or maybe goes into extents)


This does not help either. Even after additional extents has been added it still says
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taltyman
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PostPosted: Wed Oct 11, 2006 12:20 pm    Post subject: Reply with quote

might try free=close
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bablack
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PostPosted: Mon Oct 16, 2006 1:18 pm    Post subject: Reply with quote

DISP=SHR will not let you read a dataset which is being created. A NEW dataset will get an exclusive (EXC) ENQ on the DSNAME, which will lock out any SHR ENQs.
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mogens
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PostPosted: Wed Oct 18, 2006 3:12 am    Post subject: Reply with quote

Quote:

might try free=close


as no close of the dataset takes place while my job is running I don't believe this will help.

Quote:

DISP=SHR will not let you read a dataset ...


"DISP=SHR" DOES LET let me access (read) the dataset. I do not get "dataset in use" but I get the message that the dataset is empty. Probably because he cannot see the data written into the dataset by my long running job.

But can I somehow circumvent this ... ?
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Deepthi
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PostPosted: Mon Jun 04, 2007 9:45 pm    Post subject: Reply with quote

HI,

I am stuck up with some questions and it would be great if someone could help me out on this.

1. A VSAM file opened in an IO mode in one program can be opened in the Input mode in another at the same time. Is this right? If this is right, then will the updations or insertions from the program opening this file in the IO mode be accessible to the program which is browsing the file in the Input mode simultaneously.

2. Will deletion of records also be possible at that situation? Please confirm.

Thanks,
Deepthi
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expat
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PostPosted: Tue Jun 05, 2007 2:00 am    Post subject: Reply with quote

mogens

Quote:
"DISP=SHR" DOES LET let me access (read) the dataset. I do not get "dataset in use" but I get the message that the dataset is empty. Probably because he cannot see the data written into the dataset by my long running job.

But can I somehow circumvent this ... ?

OK, what is the big attraction of seeing what is being written at any particular time.

Are the buffers still in cache and not yet written, is the dataset in the NVS cache of the DASD subsystem ? 14 tracks is hardly a great amount.


Deepthi

Please start your iwn post and not tag onto another unrelated post.

What do you think the answers to your questions are ?
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dbzTHEdinosauer
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PostPosted: Tue Jun 05, 2007 3:32 am    Post subject: Reply with quote

mogens,

Sorry for the delay in posting an answer. Had to sign-off, drink a cup of coffee and relax so that I would not be a rude as you have been.

You utilize the svc99 routines, yet appear to know very little of what is going on in MVS.

1. if you have to sit there and in real-time see what your program is doing, try using BLOCK SIZE = 1 in the program and 0 or 1 buffers in your jcl dd statement.

2. The number of buffers used for the file in your job (JCL parm on DD statement, each site has their own defaults) could very well contain all the data. Until the buffers are filled and require writing to dasd or a close is issued the buffers are not flushed.

viewing a DS as it is being populated by a process is nonsensical.
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Bill Dennis
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PostPosted: Tue Jun 05, 2007 7:54 am    Post subject: Reply with quote

mogens,
I thnk the problem is that the dataset starts out as empty. Try allocating NEW and writing a header-type record so the DSCB knows it isn't empty. Close and reallocate as SHR to re-write it and I bet you can browse it while it's being written. Be sure not to code RLSE on the SPACE.
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Mervyn
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PostPosted: Tue Jun 05, 2007 8:31 am    Post subject: Reply with quote

Guys, Mogens hasn't posted since October last year. There's not too much point in scolding him now.
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Deepthi
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PostPosted: Tue Jun 05, 2007 8:36 am    Post subject: Reply with quote

Hi Expat,

I have created a new thread! (Vsam read/update).
And I believe the answers to the questions are

1. YES
2. NO.
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