Date: Sun, 5 Feb 2023 14:19:38 -0800
From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Andres Freund <andres@anarazel.de>, Tom Lane <tgl@sss.pgh.pa.us>,
	Thomas Munro <thomas.munro@gmail.com>,
	Fujii Masao <fujii@postgresql.org>,
	Postgres hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: Weird failure with latches in curculio on v15
Message-ID: <20230205221938.GA274245@nathanxps13>
References: 
 <CA+hUKGKf9Bgik=g1yPQ-crSuuziyFsScnbauG50O5328TKV1rA@mail.gmail.com>
 <20230201105514.rsjl4bnhb65giyvo@alap3.anarazel.de>
 <1369666.1675264346@sss.pgh.pa.us>
 <20230201165801.33ydbxvjdbomjqa7@alap3.anarazel.de>
 <20230201175806.GA3199959@nathanxps13>
 <20230201223555.GA3721373@nathanxps13>
 <Y9sam108o4mxZFiS@paquier.xyz>
 <20230204113029.xlcqrbxhp6lerrnc@alap3.anarazel.de>
 <20230204180354.GA258107@nathanxps13>
 <Y979NR3U5VnWrTwB@paquier.xyz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <Y979NR3U5VnWrTwB@paquier.xyz>
Archived-At: 
 <https://www.postgresql.org/message-id/20230205221938.GA274245%40nathanxps13>
Precedence: bulk

On Sun, Feb 05, 2023 at 09:49:57AM +0900, Michael Paquier wrote:
> - Should we include archive_cleanup_command into the recovery modules
> at all?  We've discussed offloading that from the checkpointer, and it
> makes the failure handling trickier when it comes to unexpected GUC
> configurations, for one.  The same may actually apply to
> restore_end_command.  Though it is done in the startup process now,
> there may be an argument to offload that somewhere else based on the
> timing of the end-of-recovery checkpoint.  My opinion on this stuff is
> that only including restore_command in the modules would make most
> users I know of happy enough as it removes the overhead of the command
> invocation from the startup process, if able to replay things fast
> enough so as the restore command is the bottleneck.
> restore_end_command would be simple enough, but if there is a wish to
> redesign the startup process to offload it somewhere else, then the
> recovery module makes backward-compatibility concerns harder to think
> about in the long-term.

I agree.  I think we ought to first focus on getting the recovery modules
interface and restore_command functionality in place before we take on more
difficult things like archive_cleanup_command.  But I still think the
archive_cleanup_command/recovery_end_command functionality should
eventually be added to recovery modules.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com