If you are seeing the error "Sorry too many clients when trying to connect to the PostgreSQL database server," it means that the maximum number of client connections has been reached for the PostgreSQL server. This can occur if there are a lot of clients trying to connect to the server at the same time, or if there are a lot of idle connections that are not being closed properly.
To resolve this issue, you can try the following:
Increase the maximum number of connections allowed by the server. You can do this by editing the "max_connections" parameter in the postgresql.conf configuration file and then restarting the PostgreSQL server.
Check for idle connections that are not being closed properly and terminate them. You can do this using the "pg_terminate_backend" function, which will kill the backend process associated with a particular connection.
Optimize your application's connection pooling and connection management to ensure that connections are being opened and closed efficiently.
If you are using a connection pooling library, try increasing the size of the connection pool to allow more connections to be made simultaneously.
If the problem persists, you may need to scale up your hardware resources (e.g., by adding more CPU or memory) to support the increased load on the server.