title: providing created_at and updated_at in mass insert for rails with postgres
body: <p>I'm doing <a href="https://www.coffeepowered.net/2009/01/23/mass-inserting-data-in-rails-without-killing-your-performance/" rel="nofollow">a mass insert</a> a la @chris-heald. If you're interacting with the database directly using raw SQL, do you need to provide the <code>created_at</code> and <code>updated_at</code> fields yourself or will you get that for free from postgres? I'm unclear whether it's Rails or postgres that does the automagical generation here.</p>