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Maximum Number of Records can be saved on Dasd

 
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aryanpa1

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Joined: 26 May 2007
Posts: 45
Location: Chennai

PostPosted: Thu May 07, 2009 10:16 pm    Post subject: Maximum Number of Records can be saved on Dasd
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Hi Team,

One of my new job is creating Millions of records in a single DASD file.I want to know what is the maximum no. of records I can place in this file. The count may go to 50 millions sometimes.

Record length is 300 bytes.

Can you please let me know the maximum no. of records I can store in this and the process how I can calculate this.

Thank you,
Pavan
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dick scherrer

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Joined: 23 Nov 2006
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Location: Inside the Matrix

PostPosted: Thu May 07, 2009 10:21 pm    Post subject:
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Hello,

Suggest you create a file with 5 million records using the recfm and blksize your "real" file will use. Then all you need to do is multiply.

One of my transaction files has around 8 million records that are 1052 bytes long and this file typically requires about 1 3390 volume.

If you search in the forum, there have been a few topics on space calculation.

I suspect that the largest possible file would be far more than you could afford to process. . .
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CICS Guy

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Joined: 18 Jul 2007
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Location: At my coffee table

PostPosted: Thu May 07, 2009 10:24 pm    Post subject:
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Take a look at SPACE parameter in a JCL
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aryanpa1

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PostPosted: Thu May 07, 2009 10:36 pm    Post subject:
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Quote:
I suspect that the largest possible file would be far more than you could afford to process. . .

Thanks Dick, Is 50 million records file can be processed easily
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Robert Sample

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Joined: 06 Jun 2008
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Location: East Dubuque, Illinois, USA

PostPosted: Thu May 07, 2009 10:46 pm    Post subject:
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If I did the math correctly, and you're not running large or extended sequential files under z/OS 1.10, you can fit about 719 million 300-byte records on a z?OS system.

Quote:
Is 50 million records file can be processed easily
another of those questions that can be answered
Yes, no, maybe
because it depends -- what do you consider "easily"? Has the JCL been optimized for buffers? Are there any constraints on the processing (for example, it is a daily process and you discover it's taking 32 hours)?
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aryanpa1

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PostPosted: Thu May 07, 2009 10:52 pm    Post subject:
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"Easily" in my sense , the time it is going to take for simple read of the file.
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CICS Guy

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PostPosted: Thu May 07, 2009 10:58 pm    Post subject:
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Robert Sample wrote:
z?OS system.
Typo or subtle hint?
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Robert Sample

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PostPosted: Thu May 07, 2009 10:58 pm    Post subject:
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Flat file, sequential read -- easy enough. How long (in elapsed time) it's going to take will depend upon the site. Factors that have a bearing include (but are not limited to) Workload Manager policy, number of active address spaces in the system, channel contention, disk contention, I/O speed, CPU speed, program processing, buffering, block size. The only way to know for sure is going to be run a significant test (say 10-100% of the file) during the normal expected window.
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Robert Sample

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Location: East Dubuque, Illinois, USA

PostPosted: Thu May 07, 2009 11:02 pm    Post subject:
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CICS guy ... typo, definitely typo. Sigh. Although subtle hint could work, too. Now, back to the LPAR I toasted this morning to see if it can be recovered or if it's time to restore from backup ...
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