Re: Re-read subscription state after lock in AlterSubscription

On Fri, Jul 3, 2026 at 9:09 PM Bertrand Drouvot
<bertranddrouvot(dot)pg(at)gmail(dot)com> wrote:
>
> On Fri, Jul 03, 2026 at 03:45:34PM +0530, Amit Kapila wrote:
>
> But while doing this and looking closely, I'm not sure AlterPublication() does
> it right. Indeed, in theory, the OID could have been re-used too (between the
> time we did the name resolution and the time we lock the publication). I think
> what is needed is something similar to RangeVarGetRelidExtended(), means do the
> name resolution, acl check (ownership) and lock acquisition, all in unison.
>

It seems RangeVarGetRelidExtended() also doesn't do the additional
invalidation handling if the caller already has an appropriate lock,
see comments [1]. Apart from that also, I am not sure it is a good
ideal to add this additional handling in Pub/Sub DDLs as in worst case
scenario even if the OID is re-used the user will face "tuple
concurrently updated" or similar ERRORs, it won't do anything wrong.
So for such rare cases, it doesn't seem worth adding this additional
re-checking machinery. Based on the same theory, I am thinking again
whether it is worth backpatching these patches? I mean these fall into
the category of improving user facing messages during Pub/Sub DDLs, so
isn't it okay to just push this work in HEAD?

[1]:
/*
* If no lock requested, we assume the caller knows what they're
* doing. They should have already acquired a heavyweight lock on
* this relation earlier in the processing of this same statement, so
* it wouldn't be appropriate to AcceptInvalidationMessages() here, as
* that might pull the rug out from under them.
*/
if (lockmode == NoLock)

--
With Regards,
Amit Kapila.