Re: BUG #17327: Postgres server does not correctly emit error for max_slot_wal_keep_size being breached

Hello, Alex.

At Mon, 13 Dec 2021 09:45:51 +0000, Alex Enachioaie  wrote in 
> I think I'm happy to leave the method of resolution up to you, I think
> the main point for me would be that when a
> replication process gets terminated as a consequence of the underlying
> temporary replication slot reaching max_slot_wal_keep_size
> that we log a specific message to indicate to the user the cause of
> the termination rather than leave it ambiguous.

Ah.. I think I got your point.  I thought that the message
"terminating process to release replication slot X" is showing the
cause for process termination but actually it doesn't mention the
reason for releasing replication slot. For persistent slots the
following message "invalidating slot" does that but that message is
absent for temporary slots.  However, in that sense, the root reason
is not clearly stated in any case.

So I'm going to propose something like the following.

  LOG:  terminating process nnnnn to release replication slot "slot"
+ DETAIL:  The WAL files retained by the slot is going to exceed max_slot_wal_keep_size.

Thanks!

-- 
Kyotaro Horiguchi
NTT Open Source Software Center