However mostly it is.<p>Consider the example with the ID&#x27;s if he would have an index with all the fields he would need, example he would only need the id and the email he could create a index with them and the query would be faster, that would be a index only scan (<a href="https:&#x2F;&#x2F;wiki.postgresql.org&#x2F;wiki&#x2F;Index-only_scans" rel="nofollow">https:&#x2F;&#x2F;wiki.postgresql.org&#x2F;wiki&#x2F;Index-only_scans</a>)