title: is having millions of tables and millions of rows within them a common practice in MySQL database design?
body: <p>I am doing database design for an upcoming web app, and I was wondering from anybody profusely using mysql in their current web apps if this sort of design is efficient for a web app for lets say 80,000 users.</p>
  
  <p>1 DB</p>
  
  <p>in DB, millions of tables for features for each user, and within each table, potentially millions of rows.</p>
  
  <p>While this design is very dynamic and scales nicely, I was wondering two things.</p>
  
  <ol>
  <li>Is this a common design in web applications today?</li>
  <li>How would this perform, time wise, if querying millions of rows.</li>
  <li>How does a DB perform if it contains MILLIONS of tables? (again, time wise, and is this even possible?)</li>
  <li>if it performs well under above conditions, how could it perform under strenuous load, if all 80,000 users accessed the DB 20-30 times each for 10 -15 minute sessions every day?</li>
  <li>how much server space would this require, very generally speaking (reiterating, millions of tables each containing potentially millions of rows with 10-15 columns filled with text)</li>
  </ol>
  
  <p>Any help is appreciated.</p>