Re: enhance wraparound warnings

On Wed, Feb 18, 2026 at 04:16:16PM +0900, Shinya Kato wrote:
> On Sat, Nov 15, 2025 at 2:05 AM Nathan Bossart <nathandbossart(at)gmail(dot)com> wrote:
>> I don't know about you, but I start getting antsy around a quarter tank.
>> In any case, I'm told that even 40M transactions aren't enough time to
>> react these days. Attached are a few patches to enhance the wraparound
>> warnings.
>
> Thank you for the patch!

Thanks for reviewing.

> I don't have a strong opinion on whether 100M is the right value, but
> I noticed a documentation issue in 0002.
>
> <programlisting>
> WARNING: database "mydb" must be vacuumed within 39985967 transactions
> DETAIL: Approximately 1.86% of transaction IDs are available for use.
> HINT: To avoid XID assignment failures, execute a database-wide
> VACUUM in that database.
> </programlisting>
>
> In maintenance.sgml, above "39985967" and "1.86%" should be updated.

Fixed.

> I'm not sure 0003 is worth the added complexity. It adds a new field
> to TransamVariablesData and a modulo check in GetNewTransactionId(),
> which is a hot path. DBAs who need early warning can already monitor
> age(datfrozenxid) with more flexible thresholds.

Yeah, looking at this one again, I'm less sure it's worth pursuing. I've
removed it.

--
nathan