you should always register any type the you use and that is not supported by doctrine, thats the most obvious example of registering tsvector type https://gist.github.com/darklow/3129096 and in your config.yml add this:
dbal:
driver: %database_driver%
host: %database_host%
port: %database_port%
dbname: %database_name%
user: %database_user%
password: %database_password%
charset: UTF8
types:
tsvector:
class: myProject\myBundle\Type\tsvectorType
mapping_types:
tsvector: tsvector