Andres Freund <andres@2ndquadrant.com> wrote:
> On 2013-11-20 05:30:39 -0800, Kevin Grittner wrote:
>> Wouldn't a database VACUUM FREEZE fix it, with WAL-logged
>> writing of everything that doesn't yet have hint bits set?
>
> Besides also being pretty expensive it still wouldn't correct the
> clog - and we don't always rely on hint bits.
I'm talking about after a fix is deployed, fixing up the possible
corruption. Can you explain where VACUUM FREEZE would not suffice?
I don't know of anywhere that we have hint bits set for a tuple and
we go fetch the clog bits in spite of that. I don't understand
where that would make sense; especially since I thought that a
database FREEZE followed by a checkpoint releases old clog space
anyway.
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company