Re: Introduce XID age and inactive timeout based replication slot invalidation

On Mon, Feb 5, 2024 at 3:15 PM Bertrand Drouvot
<bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
>
> Thanks for the patch and +1 for the idea, I think adding those new
> "invalidation reasons" make sense.

Thanks for looking at it.

> I think it's better to have the XID one being discussed/implemented before the
> inactive_timeout one: what about changing the 0002, 0003 and 0004 ordering?
>
> 0004 -> 0002
> 0002 -> 0003
> 0003 -> 0004

Done that way.

> As far 0001:
>
> "
> This commit renames conflict_reason to
> invalidation_reason, and adds the support to show invalidation
> reasons for both physical and logical slots.
> "
>
> I'm not sure I like the fact that "invalidations" and "conflicts" are merged
> into a single field. I'd vote to keep conflict_reason as it is and add a new
> invalidation_reason (and put "conflict" as value when it is the case). The reason
> is that I think they are 2 different concepts (could be linked though) and that
> it would be easier to check for conflicts (means conflict_reason is not NULL).

So, do you want conflict_reason for only logical slots, and a separate
column for invalidation_reason for both logical and physical slots? Is
there any strong reason to have two properties "conflict" and
"invalidated" for slots? They both are the same internally, so why
confuse the users?

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com