I am using codeingiter database backed sessions. It is possible that the session data could exceed the length of a text data type field (MYSQL). If I were to use LONGTEXT what are the performance ramifications of such a change? Obviously sessions are used a lot so if there is a bit performance problem, I will have to set a limit to the amount of data stored in the session.
I know some are going to argue that I shouldn't be using database backed sessions, but this is a different question so please just answer the question above.