How to speed up Batch process

atulbagewadikar · New User Joined: 15 Jun 2006 Posts: 26

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?

beruoist · New User Joined: 14 Nov 2007 Posts: 70 Location: mumbai

Hi Atul

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

Thanks in advance

Regards
Beruoist

monasu1998 · Active User Joined: 23 Dec 2005 Posts: 176 Location: India

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,

Ralph Zbrog · Posted: Fri Dec 11, 2009 1:55 pm

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.