What Inappropriate Parameter Settings Cause Unavailability of the PostgreSQL Database?

In the following cases, inappropriate parameter settings cause the database to be unavailable:

• Parameter value ranges are related to DB instance specifications.

  The maximum values of shared_buffers and max_connections are related to the DB instance physical memory. If you set these parameters inappropriately, the database will be unavailable.

• Parameter association is incorrect.
  • If log_parser_stats, log_planner_stats, or log_executor_stats is enabled, you must disable log_statement_stats. Otherwise, the database is unavailable.
  • max_connections, autovacuum_max_workers, and max_worker_processes must meet the following requirements. Otherwise, the database is unavailable.

    max_connections value + autovacuum_max_workers value + max_worker_processes value + 1 < 8388607

Solution:

1. Log in to the RDS console and query the logs to locate the incorrectly configured parameters.
2. On the Configuration page, change parameters to default values and reboot the database.
3. Configure the incorrect parameter values and restore other parameters to their original default values.