Re: CR Block copies, always 6 in 10.2.0.3?
Date: Tue, 25 Mar 2008 17:24:40 +0900
But occasionally you will see a larger number of CR copies. For example when
there is 60 processes updating a table with a NL operation (SAP, for example). One of the tests as I remember is that the buffer is not busy ('is not pinned'), then it will check the number of CR copies. If a CR copy is pinned it is not counted. So that is probably why you can speak of a soft limit.
Very impressive information.
If this is the case, we won't have any buffer lock contention for consistent read
unless physical read is involved.
This means that _db_block_max_cr_dba itself won't make any session wait or locked.