On Tue, Jun 25, 2024 at 10:31 AM Robert Haas <robertmhaas@gmail.com> wrote:
>
> On Tue, Jun 25, 2024 at 9:07 AM Andres Freund <andres@anarazel.de> wrote:
> > It's not hard - but it has downsides. It'll mean that - outside of vacuum -
> > we'll much more often not react to horizons going backwards due to
> > hot_standby_feedback. Which means that hot_standby_feedback, when used without
> > slots, will prevent fewer conflicts.
>
> Can you explain this in more detail?
If we prevent GlobalVisState from moving backward, then we would less
frequently be pushing the horizon backward on the primary in response
to hot standby feedback. Then, the primary would do more things that
would not be safely replayable on the standby -- so the standby could
end up encountering more recovery conflicts.
- Melanie