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Question on Multiple DB Positioning

 
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cybertaurean

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Joined: 22 Dec 2008
Posts: 85
Location: US

PostPosted: Wed Mar 17, 2010 12:58 pm    Post subject: Question on Multiple DB Positioning
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Hi All,

I do have the following DB structure which I need to sweep through -

Code:
                                              +01-------1+
                                              + SEGMENT1 +
                                              +----------+
                                                   |
     ---------------------------------------------------------------------------------
     |              |                              |                                 |
+02-------1+   +03-------1+                   +04-------1+                      +08-------1+
+ SEGMENT2 +   + SEGMENT3 +                   + SEGMENT4 +                      + SEGMENT8 +
+----------+   +----------+                   +----------+                      +----------+
                                                   |                                 |
                                   ------------------------------------              |
                                   |               |                  |              |
                             +05-------1+    +06-------1+       +07-------1+    +09-------1+
                             + SEGMENT5 +    + SEGMENT6 +       + SEGMENT7 +    + SEGMENT9 +
                             +----------+    +----------+       +----------+    +----------+



In case I plan to use multiple DB positioning (avoid repositions), will the code have better performance?. I will be reading SEGMENT1, SEGMENT2, SEGMENT3, SEGMENT4 and SEGMENT6.

Regards,
Sumesh
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manikawnth

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Joined: 07 Feb 2007
Posts: 61
Location: Mumbai

PostPosted: Wed Mar 17, 2010 2:50 pm    Post subject:
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How will u be reading these segments?
Just the first occurrence or u sweep thru all the occurences of these segment types.
Are the segments qualified?
The performance depends on the functionality you want thus determining the approach.
Will you be reading all the segments back and forth or just read once and leave!!!
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Sandy Zimmer

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Joined: 13 Jun 2007
Posts: 826
Location: Wilmington, DE

PostPosted: Wed Mar 17, 2010 6:50 pm    Post subject:
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Multiple PCBs within the same PSB for the same DBD - multiple positioning - is sometimes tricky. Think carefully about your process and why you need more than 1 position. If you can tell us detail about your process, we can help you decide.
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Sandy Zimmer

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Joined: 13 Jun 2007
Posts: 826
Location: Wilmington, DE

PostPosted: Thu Mar 18, 2010 6:10 pm    Post subject:
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Take a look at this post...

http://ibmmainframes.com/viewtopic.php?p=228661#228661
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cybertaurean

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Joined: 22 Dec 2008
Posts: 85
Location: US

PostPosted: Fri Mar 19, 2010 1:33 pm    Post subject: Reply to: Question on Multiple DB Positioning
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Hi All,

Apologies for the late reply.

Yes, I would want to sweep through the entire DB.

Say, I plan to use path call for SEGMENT4 and SEGMENT6 in the DB shown above, would it be better to have multiple positioning in place?

Regards,
Sumesh
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Sandy Zimmer

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Joined: 13 Jun 2007
Posts: 826
Location: Wilmington, DE

PostPosted: Fri Mar 19, 2010 4:21 pm    Post subject:
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Well, you still have not explained your process. What do you think multiple positioning has to do with your planned path call?
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manikawnth

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Joined: 07 Feb 2007
Posts: 61
Location: Mumbai

PostPosted: Mon Mar 22, 2010 11:13 am    Post subject:
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Hi Cyber,
Same concern here too...
Still i dint understand ur process?
List down step by step from which segment u want to start and the complete retrieval process and where u want to end.

Multiple positioning is useful only when u r in forward retrieval process and u want to refer a segment which is back to the current position.
Still you may not require the multiple positioning if it could be solved by some command codes.

Kindly elaborate your entire sweep sequence.

Thanks,
Manikanth
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