Given a file path name, returns the path component that represents the schema name. This function assumes that the file name lies within the schema directory. For this reason, it does not work with partitions or tables defined using their own DATA_DIRECTORY table option.

This function is useful when extracting file I/O information from the Performance Schema that includes file path names. It provides a convenient way to display schema names, which can be more easily understood than full path names, and can be used in joins against object schema names.

mysql> SELECT sys.extract_schema_from_file_name('/usr/local/mysql/data/world/City.ibd');
+---------------------------------------------------------------------------+
| sys.extract_schema_from_file_name('/usr/local/mysql/data/world/City.ibd') |
+---------------------------------------------------------------------------+
| world                                                                     |
+---------------------------------------------------------------------------+