MySQL Shell can connect to MySQL Server using both X Protocol and classic MySQL protocol. You can specify the MySQL server instance to which MySQL Shell connects globally in the following ways:

These methods of connecting to a MySQL server instance create the global session, which is a connection that can be used in all of the MySQL Shell execution modes: SQL mode, JavaScript mode, and Python mode. A MySQL Shell global object named session represents this connection, and the variable session holds a reference to it. You can also create multiple additional session objects that represent other connections to MySQL server instances, by using the shell.openSession(), mysqlx.getSession(), mysql.getSession(), or mysql.getClassicSession() function. These connections can be used in the modes where you created them, and one of them at a time can be assigned as MySQL Shell's global session so it can be used in all modes. For an explanation of session objects, how to operate on the global session, and how to create and manage multiple connections from a MySQL Shell instance, see Section 4.2, “MySQL Shell Sessions”.

All these different ways of connecting to a MySQL server instance support specifying the connection as follows:

See Connecting to the Server Using URI-Like Strings or Key-Value Pairs for more information.

If you do not specify parameters for a connection the following defaults are used:

To configure the connection timeout use the connect-timeout connection parameter. The value of connect-timeout must be a non-negative integer that defines a time frame in milliseconds. The timeout default value is 10000 milliseconds, or 10 seconds. For example:

// Decrease the timeout to 2 seconds.
mysql-js> \connect user@example.com?connect-timeout=2000
// Increase the timeout to 20 seconds
mysql-js> \connect user@example.com?connect-timeout=20000

To disable the timeout set the value of connect-timeout to 0, meaning that the client waits until the underlying socket times out, which is platform dependent.

Certain operations that open many connections to servers can take a long time to execute when one or more servers are unreachable, for example, the shell.connect() command. The connection timeout may not provide enough time for a response.

You can use the MySQL Shell configuration option connectTimeout to set the default connection timeout for any session not using AdminAPI.

Instead of a TCP connection, you can connect using a Unix socket file or a Windows named pipe. For instructions, see Section 4.3.3, “Connecting using Unix Sockets and Windows Named Pipes”.

If the MySQL server instance supports encrypted connections, you can enable and configure the connection to use encryption. For instructions, see Section 4.3.4, “Using Encrypted Connections”.

The use of LDAP and Kerberos authentication is supported for classic MySQL protocol connections. For instructions to use these, see Section 4.3.5, “Using LDAP and Kerberos Authentication”.

MySQL Shell supports SSH tunneling to connect to MySQL server instances. For instructions, see Section 4.3.7, “Using an SSH Tunnel”.

You can also request that the connection uses compression for all data sent between the MySQL Shell and the MySQL server instance. For instructions, see Section 4.3.8, “Using Compressed Connections”.

If the connection to the server is lost, you can use the \reconnect command, which makes MySQL Shell try several reconnection attempts for the current global session using the existing connection parameters. The \reconnect command is specified without any parameters or options. If those attempts are unsuccessful, you can make a fresh connection using the \connect command and specifying the connection parameters.