title: MySQL NOW() function with high precision
body: <p>I am working on an C++ application that is storing its data  through a remote MySQL database. </p>
  
  <p>One of the features is to keep up to date with the remote data as much as possible. To achieve this, I use the NOW() function to get the last update time, and when updating records, set a last_changed field to NOW().</p>
  
  <p>This works fine right now, apart form the issue that it has a maximum precision of up to one second. Causing dozens of duplicate entries, which wastes bandwidth, and having to manually remove them.</p>
  
  <p>To limit most of this bloat, I would like a precision greater than this, preferably that up to microseconds (like unix gettimeofday()). However, I can not find any information about this on the documentation. What I can find is that the NOW() function is using a variable type, capable of storing up to microsecond precision (<a href="http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html#function_now" rel="noreferrer">source</a>). But when using it, all precision after the second are zeros.</p>
  
  <p>Is there a way to force the Mysql server to use a higher precision timer (and taking potential performance for granted)? Or another way to achieve this?</p>