Fix wrong Postgres search_path set up instructions

[tdnguyen6]

In the set up instructions for Postgres database backend, the instructed command for setting search_path to the correct schema lacks public and utility, which prevented SqlAlchemy to find all those required schemas.

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[xinbinhuang]

Thanks for the PR! I like changing username to airflow_user to align with the previous section.

BTW, can you explain why the utility is required? The search_path config can actually vary across deployments because airflow allows you to construct the models in an arbitrary target schema.

[tdnguyen6]

Regarding the utility search_path, I thought that utility was required because my postgres setup issue was solved with that in the search_path.

After digging a bit more, here is the output of a preconfigured posgresql from airflow official helm chart:

psql (11.12)
Type "help" for help.

postgres=# \dn
  List of schemas
  Name  |  Owner
--------+----------
 public | postgres
(1 row)

postgres=# \dt
                     List of relations
 Schema |             Name              | Type  |  Owner
--------+-------------------------------+-------+----------
 public | ab_permission                 | table | postgres
 public | ab_permission_view            | table | postgres
 public | ab_permission_view_role       | table | postgres
 public | ab_register_user              | table | postgres
 public | ab_role                       | table | postgres
 public | ab_user                       | table | postgres
 public | ab_user_role                  | table | postgres
 public | ab_view_menu                  | table | postgres
 public | alembic_version               | table | postgres
 public | celery_taskmeta               | table | postgres
 public | celery_tasksetmeta            | table | postgres
 public | connection                    | table | postgres
 public | dag                           | table | postgres
 public | dag_code                      | table | postgres
 public | dag_pickle                    | table | postgres
 public | dag_run                       | table | postgres
 public | dag_tag                       | table | postgres
 public | import_error                  | table | postgres
 public | job                           | table | postgres
 public | log                           | table | postgres
 public | rendered_task_instance_fields | table | postgres
 public | sensor_instance               | table | postgres
 public | serialized_dag                | table | postgres
 public | sla_miss                      | table | postgres
 public | slot_pool                     | table | postgres
 public | task_fail                     | table | postgres
 public | task_instance                 | table | postgres
 public | task_reschedule               | table | postgres
 public | variable                      | table | postgres
 public | xcom                          | table | postgres
(30 rows)

postgres=# show search_path;
   search_path
-----------------
 "$user", public
(1 row)

Only public schema is used here, and the search_path is "$user", public, which is the default search_path of every new postgres user.

I have also rechecked with a fresh install of airflow using pip, the default search_path works just fine (psql (PostgreSQL) 12.8 (Ubuntu 12.8-0ubuntu0.20.04.1))

As said above, I agree with you the utility search_path is unnecessary. Moreover, I think this whole step of configuring the search_path is unnecessary as the installation works fine with the default search_path. Nevertheless, I do not guarantee that it works with older versions of Postgres.

[xinbinhuang]

As said above, I agree with you the utility search_path is unnecessary. Moreover, I think this whole step of configuring the search_path is unnecessary as the installation works fine with the default search_path. Nevertheless, I do not guarantee that it works with older versions of Postgres.

You're right. I think the intention of this section is to tell users that if they deploy airflow into a not-default schema, they may need to set the search_path the work properly.

[github-actions]

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[github-actions]

The PR is likely ready to be merged. No tests are needed as no important environment files, nor python files were modified by it. However, committers might decide that full test matrix is needed and add the 'full tests needed' label. Then you should rebase it to the latest main or amend the last commit of the PR, and push it with --force-with-lease.