title: Right choice of data type for UUID as primary key
body: <p><strong>Prior Conditions are <br></strong></p>
  
  <blockquote>
    <ol>
    <li>Table will have data in billions</li>
    <li>Table will have secondary indexes</li>
    <li>Table's primary key will be a foreign key of another table.</li>
    <li>Table will have a heavy data (another column may be Text).</li>
    </ol>
  </blockquote>
  
  <p>Primary Key must be Unique, cause my database is replicated over machine's that's why I am choosing UUID.</p>
  
  <p>PS: space is also a concern so I guess Varchar(36) might be the bad idea</p>