title: limits of number of collections in databases
body: <p>Can anyone say are there any practical limits for the number of collections in mongodb?
  They write here <a href="https://docs.mongodb.com/manual/core/data-model-operations/#large-number-of-collections" rel="noreferrer">https://docs.mongodb.com/manual/core/data-model-operations/#large-number-of-collections</a>:</p>
  
  <blockquote>
    <p>Generally, having a large number of collections has no significant
    performance penalty, and results in very good performance.</p>
  </blockquote>
  
  <p>But for some reason mongodb set limit 24000 for the number of namespaces in the database, it looks like it can be increased, but I wonder why it has some the limit in default configuration if having many collections in the database doesn't cause any performance penalty?</p>
  
  <p>Does it mean that it's a viable solution to have a practically unlimited number of collections in one database, for example, to have one collection of data of one account in a database for the multitenant application, having, for example, hundreds of thousands of collections in the database?
  If it's the viable solution to have a very large number of collections for a database for every tenant, what's the benefits of it for example versus having documents of each tenant in one collection?
  Thank you very much for your answers.</p>