#1071 - The specified key is too long. The maximum key length is 767 bytes. How to decide?

Question

MySQL

The table is copied normally, but without keys.

Answer 1

And what is the field? text? What is the key in this field?

Answer 2

See settings in parts innodb_large_prefix, innodb_page_size, innodb_file_format
https://mariadb.com/kb/en/library/innodb-limitations/
https://dev.mysql.com/doc/refman/8.0/en/innodb-res. ..
Some of the conditions were not met and the base is limited to 767 bytes per element length in the index.