Re: Time delayed LR (WAS Re: logical replication restrictions)

On Wed, Mar 8, 2023 at 9:20 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> On Wed, Mar 8, 2023 at 3:30 AM Nathan Bossart <nathandbossart@gmail.com> wrote:
> >
>
> >  IMO the current set of
> > trade-offs (e.g., unavoidable bloat and WAL buildup) would make this
> > feature virtually unusable for a lot of workloads, so it's probably worth
> > exploring an alternative approach.
>
> It might require more engineering effort for alternative approaches
> such as one I proposed but the feature could become better from the
> user perspective. I also think it would be worth exploring it if we've
> not yet.
>

Fair enough. I think as of now most people think that we should
consider alternative approaches for this feature. The two ideas at a
high level are that the apply worker itself first flushes the decoded
WAL (maybe only when time-delay is configured) or have a separate
walreceiver process as we have for standby. I think we need to analyze
the pros and cons of each of those approaches and see if they would be
useful even for other things on the apply side.

--
With Regards,
Amit Kapila.