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From: Amit Kapila <[email protected]>
To: Mark Dilger <[email protected]>
Cc: Andrew Dunstan <[email protected]>
Cc: PostgreSQL-development <[email protected]>
Cc: Robert Haas <[email protected]>
Subject: Re: Non-superuser subscription owners
Date: Thu, 18 Nov 2021 17:07:47 +0530
Message-ID: <CAA4eK1JvLmHRc0m_tv5zXZkEGDoEPQKsGgeL+Ois2msGhJ2RAQ@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<[email protected]>
	<[email protected]>

On Thu, Nov 4, 2021 at 1:20 AM Mark Dilger <[email protected]> wrote:
>
> > On Nov 1, 2021, at 10:58 AM, Mark Dilger <[email protected]> wrote:
> >
> > ALTER SUBSCRIPTION..[ENABLE | DISABLE] do not synchronously start or stop subscription workers.  The ALTER command updates the catalog's subenabled field, but workers only lazily respond to that.  Disabling and enabling the subscription as part of the OWNER TO would not reliably accomplish anything.
>
> I have rethought my prior analysis.  The problem in the previous patch was that the subscription apply workers did not check for a change in ownership the way they checked for other changes, instead only picking up the new ownership information when the worker restarted for some other reason.  This next patch set fixes that.  The application of a change record may continue under the old ownership permissions when a concurrent command changes the ownership of the subscription, but the worker will pick up the new permissions before applying the next record.
>

Are you talking about the below change in the above paragraph?

@@ -2912,6 +2941,7 @@ maybe_reread_subscription(void)
  strcmp(newsub->slotname, MySubscription->slotname) != 0 ||
  newsub->binary != MySubscription->binary ||
  newsub->stream != MySubscription->stream ||
+ newsub->owner != MySubscription->owner ||
  !equal(newsub->publications, MySubscription->publications))
  {

If so, I am not sure how it will ensure that we check the ownership
change before applying each change? I think this will be invoked at
each transaction boundary, so, if there is a transaction with a large
number of changes, all the changes will be processed under the
previous owner.

-- 
With Regards,
Amit Kapila.

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