Re: Replication slot stats misgivings

On Thu, Apr 1, 2021 at 6:19 PM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> On Tue, Mar 30, 2021 at 9:58 AM Andres Freund <andres(at)anarazel(dot)de> wrote:
> >
> > IMO, independent of the shutdown / startup issue, it'd be worth writing
> > a patch tracking the bytes sent independently of the slot stats storage
> > issues. That would also make the testing for the above cheaper...
>
> Agreed.
>
> I think the bytes sent should be recorded by the decoding plugin, not
> by the core side. Given that table filtering and row filtering,
> tracking the bytes passed to the decoding plugin would not help gauge
> the actual network I/O. In that sense, the description of stream_bytes
> in the doc seems not accurate:
>
> ---
> This and other streaming counters for this slot can be used to gauge
> the network I/O which occurred during logical decoding and allow
> tuning logical_decoding_work_mem.
> ---
>
> It can surely be used to allow tuning logical_decoding_work_mem but it
> could not be true for gauging the network I/O which occurred during
> logical decoding.
>

Agreed. I think we can adjust the wording accordingly.

--
With Regards,
Amit Kapila.