The MYI file extension is used by MySQL to store indexes for a MyISAM table. The format was developed by MySQL. MYI stands for MYIndex extension. The index defines the structure and includes a counter to check table integrity.
1326 file types use the MYI extension, but most are not compatible. You must use different applications to handle each type. The most popular program for MYI files is MySQL Enterprise Edition.
MYI files are supported on devices running Linux, Mac OS, Windows. Users can choose between 2 programs that handle this format.
MYD files are saved with corresponding FRM and MYI files. FRM contains table format data. MYI serves as the database index.
The files in ./myisam directory read and write MYI files. mi_open.c has routines that write the header sections. mi_create.c calls mi_open.c routines. myisamdef.h has structure definitions. The header has a state section written by mi_state_info_write().
To associate MYI files with MySQL, manually edit the Windows Registry HKEY_CLASSES_ROOT keys. Or right click an MYI file, choose “Open with” then “Choose another application”. Click “More applications” to select MySQL.
MySQL Server
phpMyAdmin
HeidiSQL