Can’t add new command when connection is in closed state

The error message “can’t add new command when connection is in a closed state” typically occurs when attempting to execute a command on a database connection that has been closed or lost its network connection. This commonly happens when the database connection timeout is reached or when the database server goes down while a connection is still active.

To remedy this issue, you need to ensure that the connection is open and valid before executing any commands. Here’s an example of how to handle this situation using JavaScript and the MySQL library:

  // Assuming you have created a connection object named "connection"
  
  // Check if the connection is still open
  if (connection.state === 'disconnected') {
    // Re-establish the connection
    connection.connect(function(err) {
      if (err) throw err;
      console.log('Connected to the database.');
      
      // Now you can execute your commands here
      connection.query('SELECT * FROM table', function(err, result) {
        if (err) throw err;
        console.log(result);
      });
    });
  } else {
    // Connection is still open, proceed with executing commands
    connection.query('SELECT * FROM table', function(err, result) {
      if (err) throw err;
      console.log(result);
    });
  }
  

In this example, we first check if the connection is disconnected and if so, we re-establish the connection using the connect method. Once the connection is open, we proceed with executing the desired command (in this case a SELECT query) using the query method.

By ensuring that the connection is open before executing commands, you can avoid encountering the “can’t add new command when connection is in a closed state” error.