Re: Question on REDO & SCN

On Thu, 24 Nov 2005 16:07:43 +0000, Jonathan Lewis wrote:

> It is this change that is 'just another block
> change' and therefore described by a bit of redo,
> which the manuals (incorrectly) call the 'commit record'.

But there must be something to distinguish this record from the "normal" change records. How would recovery process know which transaction has committed? When applying redo ("roll forward") finishes, uncommitted changes are rolled back. Without a clear delimiter, it is a bit unclear how can recovery know which ones should be rolled back? I believe that there must be some kind of flag saying "I am a commit record for transaction id=...".

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