On Wed, Dec 28, 2022 at 04:20:19PM -0500, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> I think the main difference between your patch and mine is that I've
>> exposed vac_update_datfrozenxid() via a function instead of a VACUUM
>> option. IMHO that feels a little more natural, but I can't say I feel too
>> strongly about it.
>
> I thought about that but it seems fairly unsafe, because that means
> that vac_update_datfrozenxid is executing inside a user-controlled
> transaction. I don't think it will hurt us if the user does a
> ROLLBACK afterward --- but if he sits on the open transaction,
> that would be bad, if only because we're still holding the
> LockDatabaseFrozenIds lock which will block other VACUUMs.
> There might be more hazards besides that; certainly no one has ever
> tried to run vac_update_datfrozenxid that way before.
That's a good point.
--
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
