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No of DB2 calls reduced-significant performance improvement?

 
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yogalakshmi

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Joined: 20 Sep 2007
Posts: 17
Location: cheenai

PostPosted: Thu Feb 05, 2009 11:44 am    Post subject: No of DB2 calls reduced-significant performance improvement?
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Hi,
Consider this program flow. A calls B,C,D,E & F.All Sub programs B,C,D,E& F query a table say,TABA using the same predicate but for different columns.
i.e,
A-> Select Col3,Col4,Col5 From TABA where Col1 = :predicate-1
B-> Select Col6,Col7,Col8 From TABA where Col1 = :predicate-1
and so on..
Now, If i combine all these 5 queries and convert it into a single query which select all columns reqd by these 5 programs and have the result in common storage so that all program can access the columns, what will be the impact in performance point of view. Will there be any improvement in performance?
TABA has approximately 130 cols, 25 M rows & 1526 pages.

Thank You in advance.
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Bharath Bhat

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Joined: 20 Mar 2008
Posts: 283
Location: chennai

PostPosted: Thu Feb 05, 2009 11:54 am    Post subject:
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Yes. It will improve the performance since you are reducing 5 DB2 calls to 1.
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sushanth bobby

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Joined: 29 Jul 2008
Posts: 1013
Location: India

PostPosted: Thu Feb 05, 2009 5:03 pm    Post subject:
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Hi,

Yes, i also agree that it will improve the performance.

If that 5 programs are independent programs and have different purposes, then the logic used in that five programs need to be brought into this main program also. Then, in this case programming concept of REUSABILITY is lost, COMPLEXITY of main program increases.

Sushanth
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yogalakshmi

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Location: cheenai

PostPosted: Thu Feb 05, 2009 5:12 pm    Post subject: Reply to: No of DB2 calls reduced-significant performance im
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Thanks sushanth & Bharath for your replies.

Sushanth,
Yes.I should consider the COMPLEXITY of the main progrmam because as of now its work is to call other programs and return the response.
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