Mysql – TINYTEXT, TEXT, MEDIUMTEXT, and LONGTEXT maximum storage sizes

You cannot assign a DEFAULT value to a TINYTEXT and you cannot create an unprefixed index on the latter.

Internally, additional objects are allocated in memory to handle TEXT (incl. TINYTEXT) columns which can cause memory fragmentation on the large recordsets.

Note that this only concerns the column's internal representation in the recordsets, not how they are stored on the disk.

To set the default to UTF-8, you want to add the following to my.cnf/my.ini

[client]
default-character-set=utf8mb4

[mysql]
default-character-set=utf8mb4


[mysqld]
collation-server = utf8mb4_unicode_520_ci
init-connect='SET NAMES utf8mb4'
character-set-server = utf8mb4

If you want to change the character set for an existing DB, let me know... your question didn't specify it directly so I am not sure if that's what you want to do.

Edit: I replaced utf8 with utf8mb4 in the original answer due to utf8 only being a subset of UTF-8. MySQL and MariaDB both call UTF-8 utf8mb4.