Andres Freund <andres@anarazel.de> writes:
> On 2016-05-18 18:25:39 -0400, Tom Lane wrote:
>> Yes, I've been wondering that too. VACUUM is not meant as a corruption
>> checker, and should not be made into one, so what is the point of this
>> flag exactly?
> Well, so far a VACUUM FREEZE (or just setting vacuum_freeze_table_age =
> 0) verified the correctness of the visibility map; and that found a
> number of bugs. Now visibilitymap grew additional responsibilities,
> with a noticeable risk of data eating bugs, and there's no way to verify
> whether visibilitymap's frozen bits are set correctly.
Meh. I'm not sure we should grow a rather half-baked feature we'll never
be able to remove as a substitute for a separate sanity checker. The
latter is really the right place for this kind of thing.
regards, tom lane