Re: Page Checksums + Double Writes

Alvaro Herrera <alvherre@commandprompt.com> wrote:
> If you get away with a new page format, let's make sure and
> coordinate so that we can add more info into the header.  One
> thing I wanted was to have an ID struct on each file, so that you
> know what DB/relation/segment the file corresponds to.  So the
> first page's special space would be a bit larger than the others.
Couldn't that also be done by burning a bit in the page header
flags, without a page layout version bump?  If that were done, you
wouldn't have the additional information on tables converted by
pg_upgrade, but you would get them on new tables, including those
created by pg_dump/psql conversions.  Adding them could even be made
conditional, although I don't know whether that's a good idea....
-Kevin