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: 2022-12-28T09:15:41Z
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,

> Thanks for the verification. BTW, do you think we should document this
> either with time-delayed replication or otherwise unless this is
> already documented?

I think this should be documented at "Shutting Down the Server" section in runtime.sgml
or logical-replicaiton.sgml, but I cannot find. It will be included in next version.

> Another thing we can investigate here why do we need to ensure that
> there is no pending send before shutdown.

I have not done yet about it, will continue next year.
It seems that walsenders have been sending all data before shutting down since ea5516,
e0b581 and 754baa. 
There were many threads related with streaming replication, so I could not pin
the specific message that written in the commit message of ea5516.

I have also checked some wiki pages [1][2], but I could not find any design about it.

[1]: https://wiki.postgresql.org/wiki/Streaming_Replication
[2]: https://wiki.postgresql.org/wiki/Synchronous_Replication_9/2010_Proposal

Best Regards,
Hayato Kuroda
FUJITSU LIMITED