Re: Snapshot too old during stress test... how to avoid

>From memory (of a course attended looong ago),
Oracle recommends one rollback segment for every three to four users.
Four rollback segments between thirty six processes does seem a little mean.

Garry

<rgaffuri_at_cox.net>
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04/06/03 13:59
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        Subject:        Snapshot too old during stress test... how to avoid

Im testing worst case scenarios right now. So Im doing batch updates,inserts,deletes and 'create table as' from a staging tablespace of approximately 5GBs to a master tablespace of approximately 11GBs.

Ive got my job queue processes set to 36 and Im running 36 at a time in the background in order to gather statistics and timing under worst case scenarios.

Im in 8.1.7.3 and I have increased the size of my RBS tablespace to 11GB for this test. I have 4 standard RBS with optimal size set to 1GB. Why would I get a snapshot too old? I would think that 11GBs of rollback would be big enough. Would increasing the number of Rollback segments avoid this even though I have the same amount of space in the tablespace?

In reality Im going to seriallize the process to avoid this and to improve performance, however, I want to stress the system.

any advice?

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Author: Garry Gillies
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