Re: [HACKERS] Why does logical replication launcher setapplication_name?

On 12/04/17 02:32, Robert Haas wrote:
> On Tue, Apr 11, 2017 at 8:11 PM, Michael Paquier
> <michael.paquier@gmail.com> wrote:
>> On Wed, Apr 12, 2017 at 3:40 AM, Tom Lane <tgl@sss.pgh.pa.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.
> 
> Wait, why do we need two ways?
> 

What do you mean by two ways? There is no way if we don't set anything.

--  Petr Jelinek                  http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training &
Services