The FILES  table provides information about InnoDB  data files. In NDB Cluster, this table also provides information about the files in which NDB Cluster Disk Data tables are stored. For additional information specific to InnoDB , see InnoDB Notes, later in this section; for additional information specific to NDB Cluster, see NDB Notes. 

The FILES  table has these columns: 

• FILE_ID 

For InnoDB : The tablespace ID, also referred to as the space_id  or fil_space_t::id . 

For NDB : A file identifier. FILE_ID  column values are auto-generated. 

• FILE_NAME 

For InnoDB : The name of the data file. File-per-table and general tablespaces have an .ibd  file name extension. Undo tablespaces are prefixed by undo . The system tablespace is prefixed by ibdata . The global temporary tablespace is prefixed by ibtmp . The file name includes the file path, which may be relative to the MySQL data directory (the value of the datadir  system variable). 

For NDB : The name of an undo log file created by CREATE LOGFILE GROUP  or ALTER LOGFILE GROUP , or of a data file created by CREATE TABLESPACE  or ALTER TABLESPACE . In NDB 8.0, the file name is shown with a relative path; for an undo log file, this path is relative to the directory DataDir/ ndb_NodeId_fs/LG ; for a data file, it is relative to the directory DataDir/ndb_NodeId_fs/TS . This means, for example, that the name of a data file created with ALTER TABLESPACE ts ADD DATAFILE ’data_2.dat’ INITIAL SIZE 256M  is shown as ./data_2.dat . 

• FILE_TYPE 

For InnoDB : The tablespace file type. There are three possible file types for InnoDB  files. TABLESPACE is the file type for any system, general, or file-per-table tablespace file that holds tables, indexes, or other forms of user data. TEMPORARY  is the file type for temporary tablespaces. UNDO LOG  is the file type for undo tablespaces, which hold undo records. 

For NDB : One of the values UNDO LOG  or DATAFILE . Prior to NDB 8.0.13, TABLESPACE  was also a possible value. 

• TABLESPACE_NAME 

The name of the tablespace with which the file is associated. 

For InnoDB : General tablespace names are as specified when created. File-per-table tablespace names are shown in the following format: schema_name / table_name . The InnoDB  system tablespace name is innodb_system . The global temporary tablespace name is innodb_temporary . Default undo tablespace names are innodb_undo_001  and innodb_undo_002 . User-created undo tablespace names are as specified when created. 

• TABLE_CATALOG 

This value is always empty. 

• TABLE_SCHEMA 

This is always NULL . 

• TABLE_NAME 

This is always NULL . 

