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

On Wed, Mar 13, 2024 at 9:24 PM Bharath Rupireddy
<bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
>
> On Wed, Mar 13, 2024 at 9:21 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> >
> > > So, how about we turn conflict_reason to only report the reasons that
> > > actually cause conflict with recovery for logical slots, something
> > > like below, and then have invalidation_cause as a generic column for
> > > all sorts of invalidation reasons for both logical and physical slots?
> >
> > If our above understanding is correct then coflict_reason will be a
> > subset of invalidation_reason. If so, whatever way we arrange this
> > information, there will be some sort of duplicity unless we just have
> > one column 'invalidation_reason' and update the docs to interpret it
> > correctly for conflicts.
>
> Yes, there will be some sort of duplicity if we emit conflict_reason
> as a text field. However, I still think the better way is to turn
> conflict_reason text to conflict boolean and set it to true only on
> rows_removed and wal_level_insufficient invalidations. When conflict
> boolean is true, one (including all the tests that we've added
> recently) can look for invalidation_reason text field for the reason.
> This sounds reasonable to me as opposed to we just mentioning in the
> docs that "if invalidation_reason is rows_removed or
> wal_level_insufficient it's the reason for conflict with recovery".
>

Fair point. I think we can go either way. Bertrand, Nathan, and
others, do you have an opinion on this matter?

--
With Regards,
Amit Kapila.