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

On Wed, Apr 8, 2020 at 5:34 AM David Steele <david(at)pgmasters(dot)net> wrote:
>
> On 4/7/20 7:32 PM, Alexander Korotkov wrote:
> > On Wed, Apr 8, 2020 at 1:34 AM Anna Akenteva <a(dot)akenteva(at)postgrespro(dot)ru> wrote:
> >> On 2020-04-08 00:45, David G. Johnston wrote:
> >>>
> >>> 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.
> >>
> >> Hello! Sorry about the confusion.
> >>
> >> This feature somehow managed to have multiple separate discussion
> >> threads:
> >> [1]
> >> https://postgr.es/m/0240c26c-9f84-30ea-fca9-93ab2df5f305%40postgrespro.ru
> >> [2]
> >> https://postgr.es/m/80f267591b373db5588d580fdfb432f0%40postgrespro.ru
> >> [3]
> >> https://postgr.es/m/195e2d07ead315b1620f1a053313f490%40postgrespro.ru
> >
> > My email client somehow merge these threads into single one. This is
> > why I missed [2] and [3] in the commit message. Sorry for that.
>
> Well, I think Ivan should have certainly replied on the original thread
> (where I marked the patch RwF after Fujii's recommendation) before
> detaching it and reviving the patch.
>
> Better yet, the original thread should not have been detached at all.
>
> Now having read the active thread it seems this patch was pushed through
> at the last moment despite some objections from Amit.
>

Yeah, I was nervous about the syntax as according to what I read in
the thread there was not a broad consensus on it. That's why
yesterday, I asked opinions from others even though I knew it is late
for PG13 to get feedback.

> I can see there are new proposals for syntax post-commit on the thread.
>
> Honestly, I'm at a loss for what to say. This just seems wrong.
>

I think we have two options now (a) Provide feedback on the thread for
syntax and see what best we can do in that regard (b) Revert and try
it for PG14. I think generally building consensus on syntax at this
stage is difficult but we can try if we want this feature for this
release. I am not very happy that it went in without more discussion
but OTOH, this is not a very big feature and if we agree on syntax
this can be part of PG13. I think code also needs some more review.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com