Re: Optimal COMMIT frequency towards Batch DMLs

Like many, many questions on this list, this one also 'depends'. This really depends on your business needs and on your resources (mostly space for large enough rollback segs or undo space). I'm usually inclined to limit commits when possible. If I've got a job which updates records and my rollback space and segment size will accommodate it, I will first entertain the idea of updating all affected records in one set. However, I realize I must be prepared to tolerate a lengthy rollback in the event of a failure. So, depending on the circumstances, I may do this update in sets based on date or some other criteria.
You may also have multiple sets of data which get updated based on different criteria and you may want to commit after each set if you want set A to remain even if set B has problems. You may also have a job where it is all or nothing where all changes must be rolled back if any fail.
Committing too frequently can also become troublesome. I've seen a procedure which committed for each iteration of a loop and caused itself ORA-01555 errors.

I'd say there's probably not a rule or a document which will say with any certainty how frequent commits should be in batch. However, what I would recommend is to search for a paper on what takes place when data is committed (or one really good source is Jonathon Lewis' book "Practical Oracle 8i", committing data is covered very early in his book / how it affects data blocks, blocks in redo, blocks in rollback, etc.) and that should 'guide' you on making a decision for each of your batch jobs depending on the circumstances. One thing for certain is that the more frequently a job commits, the more work it is doing and avoiding extra work is good where the database is concerned.

>>> VIVEK_SHARMA_at_infosys.com 04/21/03 10:21AM >>>

How may the Optimal COMMIT frequency in Batch DML Operations be determined ?

What is the Spirit behind the same ?

Any Links , Docs please ?

Thanks

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