How much UTF-8 text fits in a MySQL “Text” field?

Question

According to MySQL, a text column holds 65,535 bytes.

So if this a legitimate boundary then will it actually only fit about 32k UTF-8 characters, right?

Answer 1

However, when used as primary key, MySQL assumes that each limit of column's size adds 3 bytes to key.

mysql> alter table test2 modify code varchar(333) character set utf8;
Query OK, 0 rows affected (0.05 sec)
Records: 0  Duplicates: 0  Warnings: 0

mysql> alter table test2 modify code varchar(334) character set utf8;
ERROR 1071 (42000): Specified key was too long; max key length is 1000 bytes

Well, using long string columns as primary key is generally a bed practice, however I've came across that problem when working with database of one commercial (!) product.