using (var session = sf.OpenSession())
{
	// Если раскоментарить эту строку, то лезет эксепшен.
	//session.SetBatchSize(1); 
	Console.WriteLine("Start test");
	session.FlushMode = FlushMode.Commit;
	DateTime dtStart = DateTime.Now;
	using (var tran = session.BeginTransaction(IsolationLevel.ReadCommitted))
	{
		for (int i = 0; i < 10000; i++)
		{
			session.Save(new Person()
						    {
						        FirstName = "Персона " + i,
						        LastName = "",
						        Email = "person" + i + "@gmail.com",
						        Phone = "+7918819887" + i
						    });
		}
		Console.WriteLine("Check Point 1. Time elapsed {0}", DateTime.Now - dtStart);
		tran.Commit();
	}
	Console.WriteLine("Check Point 2. Time elapsed {0}", DateTime.Now - dtStart);
	session.Close();
}

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">		
	<session-factory>
		<property name="dialect">NHibernate.Dialect.PostgreSQL82Dialect</property>
		<property name="connection.driver_class">NHibernate.Driver.NpgsqlDriver</property>
		<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
		<property name="connection.connection_string">
			Server=localhost;Database=NHibBatchingTestDb;User ID=postgres;Password=sa;
		</property>
		<property name="proxyfactory.factory_class">NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>
		<property name="format_sql">true</property>
		<property name="show_sql">false</property>
		<property name="adonet.batch_size">20</property>
		<mapping assembly="NHibBatchingTestFixture"/>
	</session-factory>
</hibernate-configuration>