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How to speed up Batch process

 
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atulbagewadikar

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Joined: 15 Jun 2006
Posts: 26

PostPosted: Tue Feb 03, 2009 5:41 am    Post subject: How to speed up Batch process
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Hi,

What should one go for, for speeding up batch Natural process if dealing with multiple ADABAS files. PREFETCH/MULTIFETCH is the way, but is there any other way to achieve the same?
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beruoist

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Joined: 14 Nov 2007
Posts: 70
Location: mumbai

PostPosted: Tue Feb 03, 2009 1:44 pm    Post subject:
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Hi Atul

What is PREFETCH/MULTIFETCH ?...can you please share

Thanks in advance

Regards
Beruoist
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monasu1998

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Joined: 23 Dec 2005
Posts: 176
Location: India

PostPosted: Sun May 24, 2009 3:32 pm    Post subject:
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Hi Atul,

The PRE-FETCH and MULTI-FETCH are used with database access statements to improve performance and reduce I/O process.

The records fetched will be kept in a buffer area, so that the repeatative access to same data will be read from the buffer not from the database.

Thanks,
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Ralph Zbrog

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Joined: 21 Nov 2009
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Location: California

PostPosted: Fri Dec 11, 2009 1:55 pm    Post subject: Reply to: How to speed up Batch process
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To clarify, Prefetch & Multi-fetch do not reduce I/O, and do not deal with "repeatable access to same data."

They are methods by which Adabas will read-ahead for sequential commands. For each physical call to Adabas, multiple records are returned to Natural, thereby reducing inter-region communication between Adabas and Natural. Adabas and Natural do essentially the same amount of work as without Prefetch/Multi-fetch. It's the overhead that is reduced.

When applied properly, Prefetch/Multi-fetch can reduce elapsed time by as much as 80%. When applied improperly, elapsed times can increase by an order of magnitude.

The best scenario is a single, long file access; for example, a data extract or report.

If multiple file accesses are nested, the benefits of Prefetch/Multi-fetch will be reduced or even eliminated.
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