Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, Nov 30, 2010 at 11:40 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Ouch. �That seems like it could shoot down all these proposals. �There
>> definitely isn't any way to make VM crash-safe if there is no WAL-driven
>> mechanism for setting the bits.
> Heikki's intent method works fine, because the WAL record only clears
> the visibility map bits on redo; it never sets them.
Uh, no, because he also had that final WAL record that would set the
bits.
> We could actually allow the slave to set the visibility map bits based
> on its own xmin horizon.
Not in a crash-safe way, which is exactly the problem here.
regards, tom lane
