title: Storing objects/ data set with increasing number of fields
body: <p>In my application (a java based micro service) i want to persist some usage information. At the beginning i just want to store:</p>
  
  <p>accessed object -> access count</p>
  
  <p>The number of accessible objects is around 1 mio.
  But the number of fields will increase and probably also contain complex data (embedded objects).
  I am searching for a good approach or strategy to persist this data. I don't need a remote/distributed persistence layer. Local (where the service runs)/ embedded file based persistence would be sufficient.</p>
  
  <p>My first idea is to store the data in an json or xml file. All fields will be optional. My only problem with this idea is the file size: the size would increase fast and loading/ updating the data could become a problem (I/O ?).</p>
  
  <p>But what about (embedded) noSQL Databases? Is this an option, if yes what data bases should be considered?</p>
  
  <p>Are there any other options?</p>