Unable to stop pg_cron scheduler

[serpent7776]

I'm unable to stop pg_cron scheduler, even after I drop the extension. I also tried to restart the cluster and whole postgres service, but the scheduler is still running.

This is an issue, because it maintains connection to the database. In the case I install the extension to database other than postgres, it effectively prevents me from dropping/renaming the database.

It happened both with background workers and libpq connection.

I'd expect that dropping the extension should stop the scheduler.

I'm running postgresql-16-cron 1.6.4-1.pgdg22.04+1

postgres=# create extension pg_cron;

postgres=# SELECT pid,datname,application_name FROM pg_stat_activity WHERE datname = 'postgres';
  pid  | datname  | application_name  
-------+----------+-------------------
 23807 | postgres | pg_cron scheduler
 26168 | postgres | psql

postgres=# drop extension pg_cron;

postgres=# SELECT pid,datname,application_name FROM pg_stat_activity WHERE datname = 'postgres';
  pid  | datname  | application_name  
-------+----------+-------------------
 23807 | postgres | pg_cron scheduler
 26168 | postgres | psql

[TheOtherBrian1]

Can you try killing the process?

Get process id

SELECT
  pid as process_id,
  usename as database_user,
  application_name,
  backend_start as when_process_began,
  wait_event_type,
  state,
  query,
  backend_type
FROM pg_stat_activity where application_name ilike 'pg_cron scheduler';

kill process

SELECT pg_terminate_backend(<pid of the process>)

[serpent7776]

IIRC I tried to kill the backend postgres process, but it was then auto restarted, but I think I used a different query.
I'm not able to check it now, but I will try to check it in few days.

[serpent7776]

Sorry, I forgot about this. I can successfully kill the cron process, but then a new one is spawned.

postgres> SELECT
   pid as process_id,
   usename as database_user,
   application_name,
   backend_start as when_process_began,
   wait_event_type,
   state,
   query,
   backend_type
 FROM pg_stat_activity where application_name ilike 'pg_cron scheduler';
+------------+---------------+-------------------+-------------------------------+-----------------+--------+-------+------------------+
| process_id | database_user | application_name  | when_process_began            | wait_event_type | state  | query | backend_type     |
|------------+---------------+-------------------+-------------------------------+-----------------+--------+-------+------------------|
| 104195     | postgres      | pg_cron scheduler | 2024-11-26 16:25:15.464989+00 | Extension       | <null> |       | pg_cron launcher |
+------------+---------------+-------------------+-------------------------------+-----------------+--------+-------+------------------+
SELECT 1
Time: 0.007s

postgres> SELECT pg_terminate_backend(104195)
+----------------------+
| pg_terminate_backend |
|----------------------|
| True                 |
+----------------------+
SELECT 1
Time: 0.005s

postgres> SELECT
   pid as process_id,
   usename as database_user,
   application_name,
   backend_start as when_process_began,
   wait_event_type,
   state,
   query,
   backend_type
 FROM pg_stat_activity where application_name ilike 'pg_cron scheduler';
+------------+---------------+-------------------+------------------------------+-----------------+--------+-------+------------------+
| process_id | database_user | application_name  | when_process_began           | wait_event_type | state  | query | backend_type     |
|------------+---------------+-------------------+------------------------------+-----------------+--------+-------+------------------|
| 104412     | postgres      | pg_cron scheduler | 2024-11-26 16:30:04.98081+00 | Extension       | <null> |       | pg_cron launcher |
+------------+---------------+-------------------+------------------------------+-----------------+--------+-------+------------------+
SELECT 1
Time: 0.005s