> > > As long as whole block is saved in log on first after
> > > checkpoint (you made before backup) change to block.
> >
> I thought half the point of PITR was to be able to
> turn off pre-image logging so you can trade potential
> recovery time for speed without fear of data-loss.
> Didn't we have this discussion before?
> Suppose you can turn off/on PostgreSQL's atomic write on
> the fly. Which means turning on or off whether XLoginsert
> writes a copy of the block into the log file upon first
> modification after a checkpoint.
> So ALTER SYSTEM BEGIN BACKUP would turn on atomic write
> and then checkpoint the database.
> So while the OS copy of the data files is going on the
> atomic write would be enabled. So any read of a partial
> write would be fixed up by the usual crash recovery mechanism.
Yes, simple way to satisfy everyone.
Vadim
