title: What is the performance hit of using a string type vs a uuid type for a UUID primary key?
body: <p>Is there much of a speed difference for index lookups by using <code>string</code> for the primary key versus the actual <code>uuid</code> type, specifically if the string has a prefix like <code>user-94a942de-05d3-481c-9e0c-da319eb69206</code> (making the lookup have to traverse 5-6 characters before getting to something unique)?</p>