LONGTEXT [CHARACTER SET charset_name] [COLLATE collation_name]

A TEXT column with a maximum length of 4,294,967,295 or 4GB (232 - 1)
characters. Up to MySQL 3.23, the client/server protocol and MyISAM
tables had a limit of 16MB per communication packet or table row. From
MySQL 4.0, the maximum allowed length of LONGTEXT columns depends on
the configured maximum packet size in the client/server protocol and
available memory.
