Date: Mon, 2 Oct 2023 12:06:37 +0200
From: Christoph Moench-Tegeder <cmt@burggraben.net>
To: Fabrice Chapuis <fabrice636861@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: wal recycling problem
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Hi,

## Fabrice Chapuis (fabrice636861@gmail.com):

> on the other hand there are 2 slots for logical replication which display
> status extended. I don't understand why given that the confirmed_flush_lsn
> field that is up to date. The restart_lsn remains frozen, for what reason?

There you have it - "extended" means "holding wal". And as long as the
restart_lsn does not advance, checkpointer cannot free any wal beyond
that lsn. My first idea would be some long-running (or huge) transaction
which is in process (active or still being streamed). I'd recommend
looking into what the clients on these slots are doing.

Regards,
Christoph

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