title: Real time database
body: <p>I have developed a <strong>Real-Time</strong> android application which stores and retrieves 2 numbers every 3 seconds from a MYSQL database on a server, and it works fine and efficiently when the number of users is within 3 users.
  But when the number of users exceeds this limit the transaction became too slow and it seems like the database can't handle this load.
  My question: is there any types of databases (or another way) that can i use to deal with this issue ? 
  And please keep in mind the below:
  1- the problem is NOT dealing with big data, since the application is only UPDATE and doesn't INSERT a record into the database.
  2- the database is existed on a server and the middle tier between the database and the application is a PHP code.</p>