Fix Failed PostgreSQL Connection

If you encounter connection failures while connecting to a PostgreSQL database, you can try the following solutions:

1. Check the network connection: Make sure the connection is normal and try testing the connection to the database server using the ping command or other network tools.
2. Check server status: Verify if the PostgreSQL database server is running. You can check the status of the database server by running the command “pg_ctl status” in the terminal or command prompt.
3. Check the port number: Verify if the database server is using the correct port number. By default, PostgreSQL uses port 5432.
4. Check the firewall settings: If your system has a firewall, make sure that the firewall allows the port of the database server. You can try disabling the firewall settings and then attempt to connect again.
5. Check the host address and username/password: Make sure you provide the correct host address, username, and password in the connection string. You can try using the psql command-line tool to test the connection, such as psql -h host address -U username -d database name.
6. Check database permissions: Ensure that the database user has enough permissions to connect and access the database. You can try using a superuser (such as postgres) to connect, then check and modify the permissions of other users.
7. Check the log files: Review the log files of the PostgreSQL server, which are usually located in the pg_log folder within the database installation directory, to obtain more detailed error information.

If the above methods do not solve the connection failure issue, you can consider reinstalling or upgrading PostgreSQL, ensuring to follow the correct installation and configuration steps. Additionally, you can seek help on the PostgreSQL official website, mailing list, or forums for more professional technical support.