2.12. Environment Variables

This section lists all the environment variables that are used directly or indirectly by MySQL. Most of these can also be found in other places in this manual.

Note that any options on the command line take precedence over values specified in option files and environment variables, and values in option files take precedence over values in environment variables.

In many cases, it is preferable to use an option file instead of environment variables to modify the behavior of MySQL. See Section 4.2.3.3, "Using Option Files".

Variable	Description
`CXX`	The name of your C++ compiler (for running CMake).
`CC`	The name of your C compiler (for running CMake).
`CFLAGS`	Flags for your C compiler (for running CMake).
`CXXFLAGS`	Flags for your C++ compiler (for running CMake).
`DBI_USER`	The default user name for Perl DBI.
`DBI_TRACE`	Trace options for Perl DBI.
`HOME`	The default path for the mysql history file is `$HOME/.mysql_history`.
`LD_RUN_PATH`	Used to specify the location of `libmysqlclient.so`.
`LIBMYSQL_ENABLE_CLEARTEXT_PLUGIN`	Enable `mysql_clear_password` authentication plugin; see Section 6.3.7.5, "The Cleartext Client-Side Authentication Plugin".
`LIBMYSQL_PLUGIN_DIR`	Directory in which to look for client plugins.
`LIBMYSQL_PLUGINS`	Client plugins to preload.
`MYSQL_DEBUG`	Debug trace options when debugging.
`MYSQL_GROUP_SUFFIX`	Option group suffix value (like specifying `--defaults-group-suffix`).
`MYSQL_HISTFILE`	The path to the mysql history file. If this variable is set, its value overrides the default for `$HOME/.mysql_history`.
`MYSQL_HISTIGNORE`	Patterns specifying statements not to log to `$HOME/.mysql_history`.
`MYSQL_HOME`	The path to the directory in which the server-specific `my.cnf` file resides.
`MYSQL_HOST`	The default host name used by the mysql command-line client.
`MYSQL_PS1`	The command prompt to use in the mysql command-line client.
`MYSQL_PWD`	The default password when connecting to mysqld. Note that using this is insecure. See Section 6.1.2.1, "End-User Guidelines for Password Security".
`MYSQL_TCP_PORT`	The default TCP/IP port number.
`MYSQL_TEST_LOGIN_FILE`	The name of the `.mylogin.cnf` login file.
`MYSQL_UNIX_PORT`	The default Unix socket file name; used for connections to `localhost`.
`PATH`	Used by the shell to find MySQL programs.
`TMPDIR`	The directory where temporary files are created.
`TZ`	This should be set to your local time zone. See Section C.5.4.6, "Time Zone Problems".
`UMASK`	The user-file creation mode when creating files. See note following table.
`UMASK_DIR`	The user-directory creation mode when creating directories. See note following table.
`USER`	The default user name on Windows when connecting tomysqld.

For information about the mysql history file, see Section 4.5.1.3, "mysql Logging".

MYSQL_TEST_LOGIN_FILE is the path name of the login file (the file created by mysql_config_editor). If not set, the default value is %APPDATA%\MySQL\.mylogin.cnf directory on Windows and $HOME/.mylogin.cnf on non-Windows systems. See Section 4.6.6, "mysql_config_editor — MySQL Configuration Utility".

The UMASK and UMASK_DIR variables, despite their names, are used as modes, not masks:

If UMASK is set, mysqld uses ($UMASK | 0600) as the mode for file creation, so that newly created files have a mode in the range from 0600 to 0666 (all values octal).
If UMASK_DIR is set, mysqld uses ($UMASK_DIR | 0700) as the base mode for directory creation, which then is AND-ed with ~(~$UMASK & 0666), so that newly created directories have a mode in the range from 0700 to 0777 (all values octal). The AND operation may remove read and write permissions from the directory mode, but not execute permissions.

MySQL assumes that the value for UMASK or UMASK_DIR is in octal if it starts with a zero.