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

On Mon, Mar 25, 2024 at 10:33 AM shveta malik <shveta(dot)malik(at)gmail(dot)com> wrote:
>
> On Sun, Mar 24, 2024 at 3:06 PM Bharath Rupireddy
> <bharath(dot)rupireddyforpostgres(at)gmail(dot)com> wrote:
> >
> > I've attached the v18 patch set here.
>

I have a question. Don't we allow creating subscriptions on an
existing slot with a non-null 'inactive_timeout' set where
'inactive_timeout' of the slot is retained even after subscription
creation?

I tried this:

===================
--On publisher, create slot with 120sec inactive_timeout:
SELECT * FROM pg_create_logical_replication_slot('logical_slot1',
'pgoutput', false, true, true, 120);

--On subscriber, create sub using logical_slot1
create subscription mysubnew1_1 connection 'dbname=newdb1
host=localhost user=shveta port=5433' publication mypubnew1_1 WITH
(failover = true, create_slot=false, slot_name='logical_slot1');

--Before creating sub, pg_replication_slots output:
slot_name | failover | synced | active | temp | conf |
lat | inactive_timeout
---------------+----------+--------+--------+------+------+----------------------------------+------------------
logical_slot1 | t | f | f | f | f | 2024-03-25
11:11:55.375736+05:30 | 120

--After creating sub pg_replication_slots output: (inactive_timeout is 0 now):
slot_name |failover | synced | active | temp | conf | | lat |
inactive_timeout
---------------+---------+--------+--------+------+------+-+-----+------------------
logical_slot1 |t | f | t | f | f | | |
0
===================

In CreateSubscription, we call 'walrcv_alter_slot()' /
'ReplicationSlotAlter()' when create_slot is false. This call ends up
setting active_timeout from 120sec to 0. Is it intentional?

thanks
Shveta