On Sat, Feb 4, 2012 at 6:49 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Simon Riggs <simon@2ndquadrant.com> writes:
>> The cause here is data changing underneath the user. Your patch solves
>> the most obvious error, but it still allows other problems if applying
>> the backup block changes data. If the backup block doesn't do anything
>> at all then we don't need to apply it either.
>
> This is nonsense. What applying the backup block does is to apply the
> change that the WAL record would otherwise have applied, except we
> decided to make it store a full-page image instead.
Yep, you're right, my bad.
Got a head cold, so will lay off a few days from too much thinking.
--
Simon Riggs http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services