MySQL Shell 8.0  /  Getting Started with MySQL Shell  /  MySQL Shell Connections

4.3 MySQL Shell Connections

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:

  • Parameters specified with a URI-like string use a syntax such as myuser@example.com:3306/main-schema. For the full syntax, see Connecting Using URI-Like Connection Strings.

  • Parameters specified with key-value pairs use a syntax such as {user:'myuser', host:'example.com', port:3306, schema:'main-schema'}. These key-value pairs are supplied in language-natural constructs for the implementation. For example, you can supply connection parameters using key-value pairs as a JSON object in JavaScript, or as a dictionary in Python. For the full syntax, see Connecting Using Key-Value Pairs.

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

Important

Regardless of how you choose to connect it is important to understand how passwords are handled by MySQL Shell. By default connections are assumed to require a password. The password (which has a maximum length of 128 characters) is requested at the login prompt, and can be stored using Section 4.4, “Pluggable Password Store”. If the user specified has a password-less account, which is insecure and not recommended, or if socket peer-credential authentication is in use (for example when using Unix socket connections), you must explicitly specify that no password is provided and the password prompt is not required. To do this, use one of the following methods:

  • If you are connecting using a URI-like connection string, place a : after the user in the string but do not specify a password after it.

  • If you are connecting using key-value pairs, provide an empty string using '' after the password key.

  • If you are connecting using individual parameters, either specify the --no-password option, or specify the --password= option with an empty value.

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

  • user defaults to the current system user name.

  • host defaults to localhost.

  • port defaults to the X Plugin port 33060 when using an X Protocol connection, and port 3306 when using a classic MySQL protocol connection.

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.

Instead of a TCP connection, you can connect using a Unix socket file or a Windows named pipe. For instructions, see Section 4.3.2, “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 4.3.3, “Using Encrypted Connections”.

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 4.3.4, “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.