On May21, 2012, at 20:20 , Tom Lane wrote:
> I wonder whether we should dedicate a buffer status bit to show that
> the buffer has been zeroed by zero_damaged_pages and thus doesn't
> reflect what's on disk. Then we could teach autovacuum to not overwrite
> such pages.
+1. The idea of us overwriting valid pages because of transient errors sure
is scary.
> On the other hand, such an approach would mean that you
> couldn't use vacuum to forcibly clean up broken pages, so while this
> might be "safer" it's not clear it makes things more useful.
If we're concerned about this, we could always add a separate GUC
fix_damaged_pages which controls whether zero'd pages are written back
or not.
best regards,
Florian Pflug