Re: Checkpoint cost, looks like it is WAL/CRC

On Wed, Jul 06, 2005 at 21:48:44 +0100, Simon Riggs <simon@2ndquadrant.com> wrote:
> 
> We could implement the torn-pages option, but that seems a lot of work.
> Another way of implementing a tell-tale would be to append the LSN again
> as a data page trailer as the last 4 bytes of the page. Thus the LSN
> would be both the first and last item on the data page. Any partial
> write would fail to update the LSN trailer and we would be able to see
> that a page was torn. That's considerably easier than trying to write a
> torn page tell-tale to each 512 byte sector of a page as SQLServer does.

Are you sure about that? That would probably be the normal case, but are
you promised that the hardware will write all of the sectors of a block
in order?