We use the TEXT datatype for large character fields, but this only holds a maximum of 64kb of data, or 65535 non-multibyte characters (when multibyte characters are used, this could be as little as 21845 characters).

MySQL accepts any string and silently truncates it when storing.

Solution is to move to larger datatypes such as MEDIUMTEXT (holds max 2^24 = 16,777,215 bytes) or LONGTEXT (2^32 = 4,294,967,295 or 4GB).

It's important to investigate the effects this may have on our full text comment search.