Date: Mon, 6 Mar 2023 16:59:49 -0800
From: Nathan Bossart <nathandbossart@gmail.com>
To: Michael Paquier <michael@paquier.xyz>
Cc: Melanie Plageman <melanieplageman@gmail.com>,
	pgsql-hackers@postgresql.org
Subject: Re: add PROCESS_MAIN to VACUUM
Message-ID: <20230307005949.GA3266981@nathanxps13>
References: <ZAWbkiZSdFZOTS7F@paquier.xyz>
 <20230306173723.GA2934573@nathanxps13>
 <20230306194009.5cn6sp3wjotd36nu@liskov>
 <20230306202734.GA3033389@nathanxps13>
 <CAAKRu_ZJMFrO_tspzoX43h9NyEFS1nS438MoS3Yv7JxK3=jFPw@mail.gmail.com>
 <20230306211337.GA3076909@nathanxps13>
 <20230306220958.rk4b4msmybi6hm56@liskov>
 <20230306224310.GA3165453@nathanxps13>
 <CAAKRu_ZEKEsXDfFbOHRMhEROK5h1KcTcwUhERv5ZE0RQjX82_A@mail.gmail.com>
 <ZAaDPG9KJXqFU2Sr@paquier.xyz>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <ZAaDPG9KJXqFU2Sr@paquier.xyz>
Archived-At: 
 <https://www.postgresql.org/message-id/20230307005949.GA3266981%40nathanxps13>
Precedence: bulk

On Tue, Mar 07, 2023 at 09:20:12AM +0900, Michael Paquier wrote:
> -    * Do the actual work --- either FULL or "lazy" vacuum
> +    * If PROCESS_MAIN is set (the default), it's time to vacuum the main
> +    * relation.  Otherwise, we can skip this part.  If required, we'll process
> +    * the TOAST table later.
> 
> Should we mention that this part could be used for a toast table once
> we've already looped once through vacuum_rel() when toast_relid was
> set?  VACOPT_PROCESS_MAIN is enforced a few lines down the road,
> still..

That did cross my mind, but I was worried that trying to explain all that
here could cause confusion.

	If PROCESS_MAIN is set (the default), it's time to vacuum the main
	relation.  Otherwise, we can skip this part.  If processing the TOAST
	table is required (e.g., PROCESS_TOAST is set), we'll force
	PROCESS_MAIN to be set when we recurse to the TOAST table so that it
	gets processed here.

How does that sound?

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