On Tue, Dec 27, 2011 at 8:05 PM, Heikki Linnakangas <heikki.linnakan...@enterprisedb.com> wrote: > On 25.12.2011 15:01, Kevin Grittner wrote: >> >> I don't believe that. Double-writing is a technique to avoid torn >> pages, but it requires a checksum to work. This chicken-and-egg >> problem requires the checksum to be implemented first. > > > I don't think double-writes require checksums on the data pages themselves, > just on the copies in the double-write buffers. In the double-write buffer, > you'll need some extra information per-page anyway, like a relfilenode and > block number that indicates which page it is in the buffer.
How would you know when to look in the double write buffer? -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
