Date: Wed, 4 Jan 2023 09:33:04 -0800
From: Nathan Bossart <nathandbossart@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Melih Mutlu <m.melihmutlu@gmail.com>,
	Thomas Munro <thomas.munro@gmail.com>,
	"Hayato Kuroda (Fujitsu)" <kuroda.hayato@fujitsu.com>,
	"pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Subject: Re: wake up logical workers after ALTER SUBSCRIPTION
Message-ID: <20230104173304.GA296349@nathanxps13>
References: <20221202002130.GA2124877@nathanxps13>
 <20221202192101.GB2277157@nathanxps13>
 <CAGPVpCTUuKyxB5f3exgDMBRTivbN5uHVkD=YfXmgznrdnwVOQw@mail.gmail.com>
 <20221206192551.GA3078082@nathanxps13>
 <20221206212954.GA3403597@nathanxps13>
 <CAGPVpCTkdaOyBLXB435VXq0RA1cHLFQut7BPm6t8D4dsdiEXZQ@mail.gmail.com>
 <20221207181145.GA3698731@nathanxps13>
 <CAA4eK1Kr+aAaKVwKgy3kyQzuTDuc+_ahEaaOMe3ZF4SyZQSG+Q@mail.gmail.com>
 <20230103182155.GC204418@nathanxps13>
 <CAA4eK1+T1LqSRsYnwQ-FHLbRFJwedT2Bv0w6Fyz4fOAiWsaXoQ@mail.gmail.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: 
 <CAA4eK1+T1LqSRsYnwQ-FHLbRFJwedT2Bv0w6Fyz4fOAiWsaXoQ@mail.gmail.com>
Archived-At: 
 <https://www.postgresql.org/message-id/20230104173304.GA296349%40nathanxps13>
Precedence: bulk

On Wed, Jan 04, 2023 at 09:41:47AM +0530, Amit Kapila wrote:
> I am not sure if I understand the problem you are trying to solve with
> this part of the patch. Are you worried that after we mark some of the
> relation's state as READY, all the table syncs are in the READY state
> but we will not immediately try to check the two_pahse stuff and
> probably the apply worker may sleep before the next time it invokes
> process_syncing_tables_for_apply()? 

Yes.

> If so, we probably also need to
> ensure that table_states_valid is marked false probably via
> invalidations so that we can get the latest state and then perform
> this check. I guess if we can do that then we can directly move the
> restart logic to the end.

IMO this shows the advantage of just waking up the worker.  It doesn't
change the apply worker's behavior besides making it more responsive.

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