mysqldump — A Database Backup Program default  zstd  compression level is 3. The compression level setting has no effect on connections that do not use  zstd  compression. For more information, see Section 4.2.8, “Connection Compression Control” . This option was added in MySQL 8.0.18. These options are used to control which option files to read. Read this option file after the global option file but (on Unix) before the user option file. If the file does not exist or is otherwise inaccessible, an error occurs. If  file_name  is not an absolute path name, it is interpreted relative to the current directory. For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling” . Use only the given option file. If the file does not exist or is otherwise inaccessible, an error occurs. If file_name  is not an absolute path name, it is interpreted relative to the current directory. Exception: Even with  --defaults-file , client programs read  .mylogin.cnf . For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling” . Read not only the usual option groups, but also groups with the usual names and a suffix of  str . For example,  mysqldump  normally reads the  [client]  and  [mysqldump]  groups. If this option is given as  --defaults-group-suffix=_other ,  mysqldump  also reads the  [client_other]  and [mysqldump_other]  groups. For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling” . Do not read any option files. If program startup fails due to reading unknown options from an option file, --no-defaults  can be used to prevent them from being read. The exception is that the  .mylogin.cnf  file is read in all cases, if it exists. This permits passwords to be specified in a safer way than on the command line even when  --no-defaults  is used. To create .mylogin.cnf , use the  mysql_config_editor  utility. See Section 4.6.7, “mysql_config_editor — MySQL Configuration Utility” . For additional information about this and other option-file options, see Section 4.2.2.3, “Command-Line Options that Affect Option-File Handling” . Print the program name and all options that it gets from option files. • --defaults-extra-file= file_name • --defaults-file= file_name • --defaults-group-suffix= str • --no-defaults • --print-defaults 485 Option-File Options