Unindexed Properties

By default, the App Engine Datastore writes two index records for every entity property that isn't a com.google.appengine.api.datastore.Blob or a com.google.appengine.api.datastore.Text. These index records allow you to execute a variety of queries involving the property without creating a composite index.

These indexes take time to write and they take up space on disk.  If you have a property that you're absolutely positively sure you'll never want to filter or sort by, you can opt-out of the default indexing that is going on.

For example:
@Attribute(unindexed = true)
private String unindexedString;

@Attribute(unindexed = true)
List<String> favoriteColorList = new ArrayList<String>();
// ...


Continue to Automatic Values.