RE: wake up logical workers after ALTER SUBSCRIPTION

Dear Nathan,

Thank you for updating the patch!

> In v3, I moved the call to LogicalRepWorkersWakeupAtCommit() to the end of
> the function.  This should avoid waking up workers in some cases where it's
> unnecessary (e.g., if ALTER SUBSCRIPTION ERRORs in a subtransaction), but
> there are still cases where we'll wake up the workers unnecessarily.  I
> think this is unlikely to cause any real problems in practice.

I understood you could accept false-positive event to avoid missing true-negative
like ALTER SUBSCRIPTION REFRESH. +1.

> >> 02. LogicalRepWorkersWakeupAtCommit()
> >>
> >> ```
> >> +	oldcxt = MemoryContextSwitchTo(TopTransactionContext);
> >> +	on_commit_wakeup_workers_subids =
> >> lappend_oid(on_commit_wakeup_workers_subids,
> >> +
> >> 		  subid);
> >> ```
> >>
> >> If the subscription is altered twice in the same transaction, the same subid will
> >> be recorded twice.
> >> I'm not sure whether it may be caused some issued, but list_member_oid() can
> >> be used to avoid that.
> >
> > +1, list_append_unique_oid might be better.
> 
> Done in v3.

I have no comments for the v3 patch.

Best Regards,
Hayato Kuroda
FUJITSU LIMITED