If you're concerned about performance then you're better off optimising your database queries and structure. In addition, it's worthwhile minimising the number of transactions that are started/committed per user request/response. One is ideal, or two (for processing request, and then generating the response) although this is not always possible. On some consulting jobs I've seen applications have mighty performance improvements simply by making use of correct Tx management. I've seen some applications create N+1 transactions per request/response and their performance was ugly.