Re: repeated decoding of prepared transactions

On Fri, Feb 12, 2021 at 1:10 AM Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
>
> On Thu, Feb 11, 2021 at 5:37 AM Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
> > to explain the exact case to you which is not very apparent. The basic
> > idea is that we ship/replay all transactions where commit happens
> > after the snapshot has a consistent state (SNAPBUILD_CONSISTENT), see
> > atop snapbuild.c for details. Now, for transactions where prepare is
> > before snapshot state SNAPBUILD_CONSISTENT and commit prepared is
> > after SNAPBUILD_CONSISTENT, we need to send the entire transaction
> > including prepare at the commit time.
>
> This might be a dumb question, but: why?
>
> Is this because the effects of the prepared transaction might
> otherwise be included neither in the initial synchronization of the
> data nor in any subsequently decoded transaction, thus leaving the
> replica out of sync?
>

Yes.

--
With Regards,
Amit Kapila.