Does pg_isready prove that my PostgreSQL login works?
pg_isready checks whether a PostgreSQL endpoint is responding and accepting connections. It does not prove that the supplied password, database or application permissions are valid. Use a second authenticated query to verify the application’s actual access path.
Before you start
- The actual database endpoint and approved application account.
Instructions
1. Check readiness with a bounded timeout
Use the correct host and port. Supplying the intended user and database reduces irrelevant failed-login log entries, but correct credentials are not required for the readiness status itself.
pg_isready -h 127.0.0.1 -p 5432 -U appuser -d appdb -t 5Reports whether the endpoint is accepting, rejecting or not responding to PostgreSQL connection attempts.
2. Interpret readiness separately
The utility returns 0 for accepting, 1 for rejecting, 2 for no response and 3 when it could not make a valid attempt. These states describe the endpoint, not successful application authentication.
3. Perform an authenticated query
Use the actual application account and a password prompt. The constant SELECT tests query execution without reading customer tables; it does not test every application privilege.
psql -X -h 127.0.0.1 -p 5432 -U appuser -d appdb -W -v ON_ERROR_STOP=1 -c 'SELECT 1;'Connects as the chosen user and fails the command if the SQL test errors.
Check the result
- Readiness reports accepting and the authenticated query completes successfully.
- A representative authorised application operation is verified separately when permissions are part of the incident.
Troubleshooting
- pg_isready succeeds but psql is denied
- Investigate the account, password, database and matching authentication rule. Restarting a responsive database will not repair an incorrect credential.
Official references
Use the documentation for your installed version when a flag, service name or platform feature differs.