This view is a powerful tool for examining how memory is distributed among instances of different classes.
Classes are shown as a plain list. To see them grouped by namespace, use Class and namespace.
Information for a class is shown in four columns: "Class", "Objects" (number of objects), "Shallow Size" and "Retained Size" (for details please see Shallow and retained sizes).
Classes whose objects retain most memory are shown at the top, as the list is sorted by retained size.
On opening the view, estimated retained sizes are shown instead of exact sizes, which cannot be immediately calculated. The exact sizes may be obtained by using "Calculate exact retained sizes" balloon above the "Retained Size" column. However, for most classes the estimation is very close to the exact value, so there is almost no need to run exact size calculation.
You can narrow down the list by typing a class name in the text field.
Please also consider Memory | Instances by Class... (Ctrl+N), which opens all instances of a class by its name.