MySQL index too long 1071-max key length is 767 byte

Issue create Table:specified Key was too long; Max key length is 767 bytes reason database table is UTF8 encoded, where varchar (255) column has a unique key index and MySQL by default the index of a single column cannot exceed 767 bits (different versions may differ) So UTF8 character encoding, 255*3 byte exceeds the limit resolution 1 using INNODB engine, 2 enable Innodb_large_prefix option, extend constraint to 3072byte;3 re-create database; MY.CNF configuration: Default-storage-engine=innodbinnodb_large_prefix=on in General, it is not recommended to use such a long index, the performance has a certain impact ; Reference Document: https:// Dev.mysql.com/doc/refman/5.5/en/innodb-restrictions.html

MySQL index too long 1071-max key length is 767 byte