From: | Adrian Klaver <adrian(dot)klaver(at)aklaver(dot)com> |
---|---|
To: | Koen De Groote <kdg(dot)dev(at)gmail(dot)com>, PostgreSQL General <pgsql-general(at)lists(dot)postgresql(dot)org> |
Subject: | Re: On a subscriber, why is last_msg_send_time in pg_stat_subscription sometimes null? |
Date: | 2024-08-23 15:02:56 |
Message-ID: | 65d55d32-c9c3-4446-a367-d3cca3282dea@aklaver.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
On 8/23/24 07:33, Koen De Groote wrote:
> I'm running this query:
>
> SELECT subname, received_lsn, latest_end_lsn,
> last_msg_send_time, last_msg_receipt_time
> FROM pg_catalog.pg_stat_subscription;
>
> And "last_msg_send_time" will sometimes be null. All I can find in the
> documentation is that this value represents: "Send time of last message
> received from origin WAL sender; NULL for parallel apply workers"
>
> But I have no context for what parallel apply workers are or why they
> are NULL sometimes and other times not. >
> Can anyone explain?
The source has that information:
The top part explains the process.
As to the time:
/*
* There are three fields in each message received by the parallel apply
* worker: start_lsn, end_lsn and send_time. Because we have updated these
* statistics in the leader apply worker, we can ignore these fields in the
* parallel apply worker (see function LogicalRepApplyLoop).
*/
>
> Regards,
> Koen De Groote
--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com
From | Date | Subject | |
---|---|---|---|
Next Message | Matthew Tice | 2024-08-23 16:14:34 | dead tuple difference between pgstattuple and pg_stat_user_tables |
Previous Message | Morris de Oryx | 2024-08-23 14:36:21 | Re: Is there a way to translate pg_amop.amopstrategy into a description? |