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Re: delayed block cleanout (?) for active tx

From: Alberto Dell'Era <alberto.dellera_at_gmail.com>
Date: Thu, 21 Jun 2007 17:56:57 +0200
Message-ID: <4ef2fbf50706210856r4070dd79jc0399abb60c77220@mail.gmail.com>


On 6/21/07, *snipped name* wrote:
> The CR copy of the block should only be made if it's not available. If the CR
> copy created initially is still available, the second one should not have been
> created, right?

But the second one has to be consistent to a different (more recent) point in time (higher scn), hence it has to inspect the current block to check whether any modification has been performed in the meanwhile (the active tx could have committed, even). Then, it may reuse the same CR copy perhaps.

I've just re-checked everything and even after N selects, the generated redo size comes out as exactly 157612 every time.

BTW The reason I'm performing this quest is that I have an application that is generating excessive redo, and the only (apparent) change is that one critical tx is taking much more time - and other sessions are selecting the modified block.

-- 
Alberto Dell'Era
"the more you know, the faster you go"
--
http://www.freelists.org/webpage/oracle-l
Received on Thu Jun 21 2007 - 10:56:57 CDT

Original text of this message

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