I also recommend setting the innodb_log_file_size value. It must be 10 times larger than your largest record (message record).
innodb_log_file_size=500M
Otherwise, you could get the following exception:
MySQLSyntaxErrorException: Row size too large (> 8126). Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help. In current row format, BLOB prefix of 768 bytes is stored inline.