Re: [PATCH] Space reservation v02

Gregory Stark <stark@enterprisedb.com> writes:
> Well having a column in pg_class does have some advantages. Like, you could
> look at the value from an sql session more easily. And if there are operations
> which we know are unsafe -- such as adding columns -- we could clear it from
> the server side easily.

Why would there be any unsafe operations?  Surely the patch would add
sufficient logic to prevent the old version from de-fixing any page
that had already been fixed.  If this is not so, the entire concept
is broken, because you're still going to have to go to single-user mode
for a long time to make sure that the whole database is in good shape.

On the whole I agree with Heikki's earlier criticism: this is all
about guessing the future, and the odds seem high that the actual
requirements will not be what you designed for anyway.
        regards, tom lane