> On Mar 25, 2025, at 13:58, Phillip Diffley wrote:
>
> Oh I see! I was conflating the data I see coming out of a replication slot
> with the internal organization of the WAL. I think the more specific question
> I am trying to answer is, as a consumer of a replication slot, how do I
> reas
> You're looking for Standby Status Update
Awesome! I completely missed that.
> Transactions are always presented to the output plugin in commit order
Ok great. I think that is what I needed to know.
Just to confirm, it sounds like the order messages are sent from the output
plugin is what matt
> On Mar 26, 2025, at 07:55, Phillip Diffley wrote:
> Just to confirm, it sounds like the order messages are sent from the output
> plugin is what matters here. When you update confirmed_flush_lsn to LSN "A",
> any messages that were sent by the output plugin after the message with LSN
> "A"
> On Mar 25, 2025, at 20:56, Phillip Diffley wrote:
>
> Is there a message type that is used to confirm what logs have been
> successfully consumed?
You're looking for Standby Status Update:
https://www.postgresql.org/docs/current/protocol-replication.html#PROTOCOL-REPLICATION-STAN
> You shouldn't need to manually advance the replication slot.
> The client is also expected to send back regular messages letting the
publisher / primary know that it has successfully consumed up to a
particular point
I was thinking of these as the same thing, but it sounds like they are
differen
Oh I see! I was conflating the data I see coming out of a replication slot
with the internal organization of the WAL. I think the more specific
question I am trying to answer is, as a consumer of a replication slot, how
do I reason about what replication records will be made unavailable when I
conf
Missed this question!
> On Mar 25, 2025, at 09:56, Phillip Diffley wrote:
> But when processing data from a replication slot, we confirm rows that have
> been processed and can be deleted from the WAL based on the LSN (eg. with
> pg_replication_slot_advance). How does postgres identify what par
> On Mar 25, 2025, at 09:56, Phillip Diffley wrote:
> 1. Every DML operation (insert, update, delete, truncate) will have a row in
> the WAL and that row will have an LSN assigned to it.
> 2. The LSNs are assigned when the operation happens.
> 3. Operations within a transaction are written to
