Re: CR Block copies, always 6 in 10.2.0.3?

I am not sure how this works but for example in Grid Control repository sometimes I see 400 CR copies for an unique index!

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On Mon, Mar 24, 2008 at 1:10 AM, amonte <ax.mount_at_gmail.com> wrote:



> Hi all

>

> I read from somewhere, I think the wait interface book where it states

> that the number of clone copies of data block is governed by

> _DB_BLOCK_MAX_CR_DBA which is set to 6. If there will be more than 6 copies

> then Oracle will wait for the buffer, this is what I dont get, wait?

>

> So I fired up 7 sessions and see what kind of wait is this! I updated the

> same table (EMP from scott tiger), 14 rows in same data block and each

> session updates a row, then each session fires a query agaisnt EMP. I

> noticed that the number of CR is never more than 6 despite having 7 updates

> concurrently and I dont see what is really going on. Does this mean whenever

> the 7th CR block is being cloned one of 6 previous CR is being overwritten

> or "destroyed"?

>

> I did the test in 10.2.0.3.

>

> TIA

>

> Alex

>

>

>


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