Re: pgsql: Implement waiting for given lsn at transaction start

On Tue, Apr 7, 2020 at 2:27 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> Alexander Korotkov <akorotkov(at)postgresql(dot)org> writes:
> > Implement waiting for given lsn at transaction start
> > This commit adds following optional clause to BEGIN and START TRANSACTION
> > commands.
> > WAIT FOR LSN lsn [ TIMEOUT timeout ]
>
> This seems like a really carelessly chosen syntax --- *three* new
> keywords, when you probably didn't need any. Are you not aware that
> there is distributed overhead in the grammar for every keyword?
> Plus, each new keyword carries the risk of breaking existing
> applications, since it no longer works as an alias-not-preceded-by-AS.
>
> I have no particular opinion on the value of the feature, but I wish
> a different syntax had been chosen.
>

I was curious whether the syntax got this kind of discussion, followed the
discussion link, and the last email seen reads:

"""
> Worse, it was marked Needs Review even though no new patch was provided.
>
> I'm going to set this back to Returned with Feedback. If anyone has a
good
> reason that it should be in the CF we can always revive it.

+1.
"""

While there is lots of discussion it ended up with the thread at "returned
with feedback" (a month ago) and now we have a commit. There seems to be
other relevant discussion not linked to.

David J.