My problem:
Airflow scheduler is not assigning tasks.
Background:
I have Airflow running successfully on my local machine with sqlitedb. The sample dags as well as my custom DAGs ran without any issues. When I try to migrate from sqlite database to Postgres (using this guide), the scheduler no longer seems to be assigning tasks. The DAG get stuck on "running" state but no task in any DAGs ever gets assigned a state.
Troubleshooting steps I've taken
Scheduler Log
The scheduler log keeps posting out this WARNING but I have not been able to use it to find any useful information aside form this other post with no responses.
[2020-04-08 09:39:17,907] {dag_processing.py:556} INFO - Launched DagFileProcessorManager with pid: 44144
[2020-04-08 09:39:17,916] {settings.py:54} INFO - Configured default timezone <Timezone [UTC]>
[2020-04-08 09:39:17,927] {settings.py:253} INFO - settings.configure_orm(): Using pool settings. pool_size=5, max_overflow=10, pool_recycle=1800, pid=44144
[2020-04-08 09:39:19,914] {dag_processing.py:663} WARNING - DagFileProcessorManager (PID=44144) exited with exit code -11 - re-launching
Environment
Postgres was installed using postgresapp. Updated postgresapp to version 2.3.3e. PostgresSQL is still version 12.1 but by updating the postgresapp, the issue was solved.