Re: Why does logical replication launcher set application_name?

On Wed, Apr 12, 2017 at 3:40 AM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> I notice looking at pg_stat_activity that the logical replication launcher
> sets its application_name to "logical replication launcher". This seems
> inconsistent (no other standard background process sets application_name),
> redundant with other columns that already tell you what it is, and an
> unreasonable consumption of horizontal space in the tabular output.
> Can we drop that? If we do have to have something like that, what about
> putting it in the "query" field where it's much less likely to be
> substantially wider than any other entry in the column?

It seems to me that the logic behind that is to be able to identify
easily the logical replication launcher in pg_stat_activity, so using
the query field instead sounds fine for me as we need another way than
backend_type to guess what is this bgworker.
--
Michael