Re: Failed transaction statistics to measure the logical replication progress

On Tue, Nov 23, 2021 at 3:21 PM Greg Nancarrow <gregn4422(at)gmail(dot)com> wrote:
>
> On Sat, Nov 20, 2021 at 1:11 AM Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> >
> > I'm concerned that these new names will introduce confusion; if we
> > have last_error_relid, last_error_command, last_error_message,
> > last_error_time, and last_error_xid, I think users might think that
> > first_error_time is the timestamp at which an error occurred for the
> > first time in the subscription worker.
>
> You mean you think users might think "first_error_time" is the
> timestamp at which the last_error first occurred (rather than the
> timestamp of the first of any type of error that occurred) on that
> worker?

I felt that "first_error_time" is the timestamp of the first of any
type of error that occurred on the worker.

>
> > ... Also, I'm not sure
> > last_error_count is not clear to me (it looks like showing something
> > count but the only "last" one?).
>
> It's the number of times that the last_error has occurred.
> Unless it's some kind of transient error, that might get resolved
> without intervention, logical replication will get stuck in a loop
> retrying and the last error will occur again and again, hence the
> count of how many times that has happened.
> Maybe there's not much benefit in counting different errors prior to
> the last error?

The name "last_error_count" is somewhat clear to me now. I had felt
that since the last error refers to *one* error that occurred last and
it’s odd there is the count of it.

Regards,

--
Masahiko Sawada
EDB: https://www.enterprisedb.com/