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From "RPost" <rp0...@pacbell.net>
Subject Re: Derby architecture/design documents
Date Mon, 07 Feb 2005 02:44:36 GMT
> "Dibyendu Majumdar" wrote:

> Although Derby uses LogInstant, it does not save this with the page data.
Instead, a page version >number is stored. The page version number is also
stored in the log records associated with the page

Mike's comments "As you say in derby all the log records are associated with
a page, and thus have a page version number. That page version number in the
log is compared with the page version number of the page during redo to
determine if the log record needs to be applied."

Does this mean that the page number is stored both in the 'in memory' image
of the page and also in the version of the page written to disk?

Are changes to pages ever written to disk before the changes are actually
committed? For example, if the page cache is full?



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