GSAM file shows more records after abend.

IBM's Hierarchical DBMS and Transaction Manager (IMS DC).
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Shriram
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GSAM file shows more records after abend.

Post by Shriram » Fri Jun 17, 2016 3:20 pm

Hi
Iam running an IMS DB program with check-point restart logic in it. The Job abended after 588th record. Check-point is issued after 100 records. Output file is a GSAM file. I was expecting that my output file to have only 500 records but I don't know why it shows 588 records! Why this happnes? Why all the records are written to the output and not just 500?




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Re: GSAM file shows more records after abend.

Post by nicc » Fri Jun 17, 2016 3:34 pm

Perhaps your coding is wrong.


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Anuj Dhawan
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Re: GSAM file shows more records after abend.

Post by Anuj Dhawan » Fri Jun 17, 2016 4:47 pm

"It's working as designed"! :)

With Check-point restart all the records which are processed successfully will be written to the output however, when you restart the program will start processing from 501[sup]st[/sup] record.


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Re: GSAM file shows more records after abend.

Post by Shriram » Sat Jun 18, 2016 9:15 am

But then how about those 88 records?? What will happen to them?



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Re: GSAM file shows more records after abend.

Post by Anuj Dhawan » Sat Jun 18, 2016 10:48 am

They are processed again from the input and written to output. In the case of abend you are not sure about the integrity of the data and you restart from the last successful execution even if it means processing some records again, but you know all is working as you intended it to.


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enrico-sorichetti
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Re: GSAM file shows more records after abend.

Post by enrico-sorichetti » Sat Jun 18, 2016 5:25 pm

GSAM files will be in an unpredictable state until ALL the IMS recovery actions have been done.


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Shriram
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Re: GSAM file shows more records after abend.

Post by Shriram » Mon Jun 27, 2016 2:10 pm

enrico-sorichetti wrote:GSAM files will be in an unpredictable state until ALL the IMS recovery actions have been done.
You mean this is the rason that i see those extra records?




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Re: GSAM file shows more records after abend.

Post by enrico-sorichetti » Mon Jun 27, 2016 6:06 pm

You mean this is the rason that i see those extra records?
yes.


cheers
enrico
When I tell somebody to RTFM or STFW I usually have the page open in another tab/window of my browser,
so that I am sure that the information requested can be reached with a very small effort 8-)


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Shriram
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Re: GSAM file shows more records after abend.

Post by Shriram » Thu Jun 30, 2016 3:05 pm

Now because the abend has happened so the GSAM is in unpredictable state. But then such unpredictable state does not come that's why we write check-point restart logic. If it's not being taken care then what's the benefit of the check-point restart in the program?




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Re: GSAM file shows more records after abend.

Post by enrico-sorichetti » Thu Jun 30, 2016 3:32 pm

If it's not being taken care
IMS has all the things in place to provide data integrity and consistency across failures

If You do nothing DBs state will be unpredictable

If, on the other side,
You , Your operations, Your support, Your whatever f****** name You call it do what the IBM manuals tell to do

the data bases will be updated only once, the input GSAM DB records will be processed only once, the output GSAM DB will not contain any duplicate records.


it is almost time to lock the topic :evil:


cheers
enrico
When I tell somebody to RTFM or STFW I usually have the page open in another tab/window of my browser,
so that I am sure that the information requested can be reached with a very small effort 8-)


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Shriram
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Re: GSAM file shows more records after abend.

Post by Shriram » Mon Jul 04, 2016 12:23 pm

Thanks!



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