NHibernate Transactions on Reads

Question

I have read the documentation and explanation on why it is highly recommended to use transactions on read operations in NH. However, I still haven\'t totally \"bought\" into

Answer 1

This post from one of the authors might have your answer:

Even if we are only reading data, we want to use a transaction, because using a transaction ensure that we get a consistent result from the database. NHibernate assume that all access to the database is done under a transaction, and strongly discourage any use of the session without a transaction.

Leaving aside the safety issue of working with transactions, the assumption that transactions are costly and we need to optimize them is a false one. As already mentioned, databases are always running in transaction. And databases have been heavily optimized to work with transactions. The question is whatever this is per statement or per batch. There is some amount of work that need to be done to create and dispose a transaction, and having to do it per statement is actually more costly than doing it per batch.