Re: SCN scheme 3

Since no-one else has answered, I'll
take a guess.

Historically OPS used to have two options for synchronising SCNs across multiple
instances, 'broadcast on commit' and 'Lamport'. The default was Lamport, but if you modified the max_commit_propagation_delay downwards from its default value of 700 (centiseconds) then at some low value (possibly about 10) the database would switch to 'broadcast on commit'.

I guess Oracle have come up with a clever new (lazy ?) way of maximising the degree of synchronisation whilst minimising the delay at any one instance, and called it 'Scheme 3'.

Have you modified the value of max_commit_propagation_delay or any other parameter which looks like a timing parameter to make this happen ? Or are you on some platform with a super-low latency for messaging ?

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

  The educated person is not the person   who can answer the questions, but the   person who can question the answers -- T. Schick Jr

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• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: 28 March 2003 21:18

> List, does anybody know what this means:
>
> SCN scheme 3
>
> It occurs it the alert log upon startup.
> thanks,
>
> David Ehresmann
>

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Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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