Hi,
On 9/25/23 10:44 AM, Drouvot, Bertrand wrote:
Hi,
On 9/23/23 3:38 AM, Amit Kapila wrote:
On Fri, Sep 22, 2023 at 6:01 PM Drouvot, Bertrand
<bertranddrouvot...@gmail.com> wrote:
There is a difference here that we also need to prevent removal of
rows required by sync_slots. That could be achieved by physical slot
(and hot_standby_feedback). So, having a requirement to have physical
slot doesn't sound too unreasonable to me. Otherwise, we need to
invent some new mechanism of having some sort of placeholder slot to
avoid removal of required rows.
Thinking about it, I wonder if removal of required rows is even possible
given that:
- we don't allow to logical decode from a sync slot
- sync slot catalog_xmin <= its primary counter part catalog_xmin
- its primary counter part prevents rows removal thanks to its own catalog_xmin
- a sync slot is removed as soon as its primary counter part is removed
In that case I'm not sure how rows removal on the primary could lead to remove
rows
required by a sync slot. Am I missing something? Do you have a scenario in mind?
Please forget the above questions, it's in fact pretty easy to remove rows on
the primary that
would be needed by a sync slot.
I do agree that having a requirement to have physical slot does not sound
unreasonable then.
Regards,
--
Bertrand Drouvot
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com
