Re: Slow rollbacks are hampering application

I'm not sure what is happening here. Under normal conditions, if user A performs a DML operation, the block data is copied into the rollback segments and the block's header updated with the rollback block's address. If user B was to select this changed data, the read consistent image would be read from the rollback segment (referenced by the address held in the data block).

If the transaction is rolled back, the rollback data is copied back to the data block and the block header is then updated. So the read consistant image is available until the header is updated, then the data block's data is available.

Based upon this understanding, I'm not sure how you would get these symptoms, unless the message is being sent by your application?

It is worth noting that rollbacks are inherantly slower, as Oracle (and practice) dictates that the vast majority of transactions commit data rather than rollback.

If you want further information on the rollback processing of an Orace database, Oracle has several white paper' on the subject which are available via their web-site.

Best of luck

Nick

Rian Hawkins wrote in message <8RsR2.2726$kr1.50097_at_news7.ispnews.com>...
>We have a form written in Visual C++ 5.0 using ODBC in Oracle 7.3.3 running
>on NT server 4.0
>When records are deleted, then the operator hits Cancel, the deletes are
>rolled back. The problem is that the operator goes back into the screen
and
>the "Cancelled Deleted" records haven't come back yet. The customer
>discovered this during testing and want it fixed despite the admittedly
rare
>occasion this might happen.
>
>Is there a way to determine when the rollback is finished?
>
>Thanks in advance for any help
>
>Rian Hawkins
>Sys Admin
>Comptek Federal Systems
>
>
>
Received on Sat Apr 17 1999 - 19:37:50 CDT