Subject RE: [IB-Architect] Next ODS change (was: System table change)
Author Ann Harrison
At 12:53 AM 11/8/2000 -0400, Claudio Valderrama C. wrote:
> >
> > Other things to consider for the ODS change include:
> >
> > 1) Drop page checksum
>It seems they are already abandoned.

Right. So why carry the space around in the page header?

> > 2) Add page generation at bottom of page for a consistency check.
>Explain, please.

Every page has a generation number which reflects the number of
times it has been written. That's part of the overall write ahead
log work Charlie did. One problem I worry about from time to time
is partial page writes - due to bad alignment part but not all of
a page is written when the system crashes. The checksum used to
catch that. A cheaper alternative is to keep a copy of the page
generation number at the bottom of the page.