Horton

RE: Exit walsender before confirming remote flush in logical replication

Hayato Kuroda (Fujitsu) <kuroda.hayato@fujitsu.com>

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From: "Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>
To: 'Amit Kapila' <amit.kapila16@gmail.com>
Cc: Dilip Kumar <dilipbalaut@gmail.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2022-12-28T02:49:53Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Add wal_sender_shutdown_timeout GUC to limit shutdown wait for replication

  2. pg_upgrade: Add --copy option

  3. Prevent possibility of panics during shutdown checkpoint.

  4. Support clean switchover.

Dear Amit,

> In logical replication, it can happen today as well without
> time-delayed replication. Basically, say apply worker is waiting to
> acquire some lock that is already acquired by some backend then it
> will have the same behavior. I have not verified this, so you may want
> to check it once.

Right, I could reproduce the scenario with following steps.

1. Construct pub -> sub logical replication system with streaming = off.
2. Define a table on both nodes.

```
CREATE TABLE tbl (id int PRIMARY KEY);
```

3. Execute concurrent transactions.

Tx-1 (on subscriber)
BEGIN;
INSERT INTO tbl SELECT i FROM generate_series(1, 5000) s(i);

	Tx-2 (on publisher)
	INSERT INTO tbl SELECT i FROM generate_series(1, 5000) s(i);

4. Try to shutdown publisher but it will be failed.

```
$ pg_ctl stop -D publisher
waiting for server to shut down............................................................... failed
pg_ctl: server does not shut down
```

Best Regards,
Hayato Kuroda
FUJITSU LIMITED