Re: Avoid resetting subscription two_phase state to pending when already enabled

Hi,

On Thu, Oct 29, 2026 at 03:52:46PM +0530, vignesh C wrote:
> There is the following documentation mentioning that slots must be
> created with the same parameters of the subscription at [1].
> When altering the slot_name, the failover and two_phase property
> values of the named slot may differ from the counterpart failover and
> two_phase parameters specified in the subscription. When creating the
> slot, ensure the slot properties failover and two_phase match their
> counterpart parameters of the subscription. Otherwise, the slot on the
> publisher may behave differently from what these subscription options
> say: for example, the slot on the publisher could either be synced to
> the standbys even when the subscription's failover option is disabled
> or could be disabled for sync even when the subscription's failover
> option is enabled.
>
> I'm not sure if this should be handled here as it is documented already.

I agree about the documentation, but the patch introduces a regression: without
the patch, two_phase is enabled on the replacement slot. With the patch, it remains
disabled.

It might be worth fixing, as preserving 'e' only when slot_name is unchanged
should be simple enough.

Regards,

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