[WIP] Double-write with Fast Checksums

Folks,

Please find attached a new revision of the double-write patch. While
this one still uses the checksums from VMware, it's been
forward-ported to 9.2.

I'd like to hold off on merging Simon's checksum patch into this one
for now because there may be some independent issues.

Questions? Comments? Brickbats?

Cheers,
David.
--
David Fetter <david(at)fetter(dot)org> http://fetter.org/
Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter
Skype: davidfetter XMPP: david(dot)fetter(at)gmail(dot)com
iCal: webcal://www.tripit.com/feed/ical/people/david74/tripit.ics

Remember to vote!
Consider donating to Postgres: http://www.postgresql.org/about/donate