Logical replication from PG 15.3 to 15.2 has been running without problems
until a few days ago.
Now the subscriber shows repeated messages like:
```
2023-07-29 08:25:04.523 UTC [26] LOG: checkpoint complete: wrote 8692 buffers
(53.1%); 0 WAL file(s) added, 1 removed, 14 recycled; write=269.921 s,
sync=0.485 s, total=270.438 s; sync files=37, longest=0.224 s, average=0.014 s;
distance=230568 kB, estimate=436766 kB
2023-07-29 08:25:34.550 UTC [26] LOG: checkpoint starting: time
2023-07-29 08:27:55.699 UTC [142] ERROR: could not receive data from WAL
stream: server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.
2023-07-29 08:27:55.702 UTC [159] LOG: logical replication apply worker for
subscription "<SUB_NAME>" has started
2023-07-29 08:27:55.706 UTC [1] LOG: background worker "logical replication
worker" (PID 142) exited with exit code 1
```
And the publisher shows repeated messages like:
```
2023-07-29 08:24:50.341 UTC [530982] STATEMENT: START_REPLICATION SLOT "<SUB
NAME>" LOGICAL 37D1/1E0DD9A0 (proto_version '3', publication_names '"<PUB
NAME>"')
2023-07-29 08:27:36.956 UTC [530982] LOG: terminating walsender process due to
replication timeout
2023-07-29 08:27:36.956 UTC [530982] CONTEXT: slot "<SUB NAME>", output plugin
"pgoutput", in the change callback, associated LSN 37D0/F9E8C2E8
```
I can connect using `psql` from either node back to the other. As far as I have
been able to determine no routing or firewall changes have been made.
Reading other similar reports suggests that deleting and recreating the sub
will fix the problem, but I'd like to understand/avoid it.
Any suggestions on how to track this down would be appreciated.
-
