[pgpool-general: 9400] Question about backend_application_name

[Ron Johnson]

PgPool 4.5.4

Three node pgpool cluster:
Node0 = Postgresql primary
Node1 = Postgresql streaming replica
Node2 = PgPool leader, where the VIP sits.

https://www.pgpool.net/docs/45/en/html/runtime-config-backend-settings.html

The docs consistently refer to setting backend_application_nameX to
"serverX", so that's what I did:

But should it really be set to "walreceiver"?  Should both
backend_application_name0 and backend_application_name1 be set to
"walreceiver" even though it's only running on Node1?

Node 0:
postgres=# select pid, application_name, client_hostname
from pg_stat_activity
where application_name != '';
   pid   |    application_name    | client_hostname
---------+------------------------+-----------------
 3112451 | walreceiver            | FISPCDSPGS302b
 1177629 | psql                   | FISPCDSPGS302c
 1221366 | psql                   | FISPCDSPGS302c
 1325036 | psql                   | FISPCDSPGS302c
 1171884 | psql                   | FISPCDSPGS302c
 3865948 | PostgreSQL JDBC Driver | FISPCDSPGS302c
 1334650 | psql                   |
 1261549 | PostgreSQL JDBC Driver | FISPCDSPGS302c
 1261614 | PostgreSQL JDBC Driver | FISPCDSPGS302c
 1261622 | PostgreSQL JDBC Driver | FISPCDSPGS302c
 1261624 | PostgreSQL JDBC Driver | FISPCDSPGS302c
 1139422 | psql                   | FISPCDSPGS302c
 1267007 | PostgreSQL JDBC Driver | FISPCDSPGS302c
 1177681 | psql                   | FISPCDSPGS302c
 1208143 | psql                   | FISPCDSPGS302c
 1208198 | psql                   | FISPCDSPGS302c
 1273655 | psql                   | FISPCDSPGS302c
 1296530 | psql                   | FISPCDSPGS302c
 1300468 | psql                   | FISPCDSPGS302c
 1300643 | psql                   | FISPCDSPGS302c
(20 rows)

Node 1:

postgres=# select pid, application_name, backend_type
from pg_stat_activity
where client_hostname is null;
   pid   | application_name |   backend_type
---------+------------------+-------------------
 2694716 | psql             | client backend
 1437627 |                  | startup
 1437626 |                  | background writer
 1437625 |                  | checkpointer
 1437628 |                  | walreceiver
(5 rows)

$ psql -h FISPCDSPGS302 -p9999 cdsmultip
psql (16.8)
Type "help" for help.

cdsmultip=#
cdsmultip=# pgpool show backend_application_name0;
 backend_application_name0
---------------------------
 server0
(1 row)

cdsmultip=# pgpool show backend_application_name1;
 backend_application_name1
---------------------------
 server1
(1 row)

cdsmultip=# pgpool show backend_application_name2;
 backend_application_name2
---------------------------

(1 row)


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