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Re: [19] CREATE SUBSCRIPTION ... SERVER

Amit Kapila <amit.kapila16@gmail.com>

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From: Amit Kapila <amit.kapila16@gmail.com>
To: Jeff Davis <pgsql@j-davis.com>
Cc: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>, Masahiko Sawada <sawada.mshk@gmail.com>, Shlok Kyal <shlok.kyal.oss@gmail.com>, Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>, Joe Conway <mail@joeconway.com>, pgsql-hackers@postgresql.org
Date: 2026-03-17T05:59:40Z
Lists: pgsql-hackers 
On Mon, Mar 16, 2026 at 9:56 PM Jeff Davis <pgsql@j-davis.com> wrote:
>
> On Mon, 2026-03-16 at 11:08 +0530, Amit Kapila wrote:
> > Won't it be sufficient if we just reset MySubscriptionCtx here or in
> > callback subscription_change_cb()?
>
> The old and new subscriptions are compared against eachother (to see
> whether to restart the worker or not), so they both have to exist at
> the same time. If we put them in the same context, then we can't reset
> it.
>
> I suppose we could have just two contexts and switch back and forth
> between them, resetting the last one. But that doesn't seem to be worth
> the trouble.
>

Yeah, or the other possibility could be to let the newsub information
get allocated in the current transaction context and reset the
subscription context if we decide not to exit from the worker. Then
copy/get the subscription info in subscription context but not sure if
that is worth it. The minor oddity in the proposed approach is that
the worker will exit in many cases after allocating the new context
but that may be the best we can do here.

-- 
With Regards,
Amit Kapila.

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Document new catalog columns, missed in commit 8185bb5347.

  2. Refactor to remove ForeignServerName().

  3. GetSubscription(): use per-object memory context.

  4. Fix dependency on FDW's connection function.

  5. ALTER SUBSCRIPTION ... SERVER test.

  6. Fix pg_dump for CREATE FOREIGN DATA WRAPPER ... CONNECTION.

  7. Clean up postgres_fdw/t/010_subscription.pl.

  8. CREATE SUBSCRIPTION ... SERVER.

  9. Allow upgrades to preserve the full subscription's state.