Memory Snapshot Comparison
See Also
The Memory Snapshot Comparison window displays a comparison of two memory snapshots.
This window opens in the main editor window after you choose the Compare
Snapshots command from the main menu and select two memory snapshots.
Alternatively, you can click the compute the difference button
(
)
in the toolbar of a memory snapshot.
The window displays a table with details about the number of
object instances and the amount of memory occupied by the
objects at the time the snapshots were taken.
The IDE compares the two snapshot and for each object
displays the changes that occurred between the snapshots.
The comparison that is displayed depends upon the data that is contained in the snapshots.
The data that is captured in the snapshot depends upon the options that were selected
for the profiling session.
Sampling Comparison
If the Quick (sampled) option was selected for the profiling session,
the comparison provides details on the difference between the number of live objects
in the two snapshots.
The table in the Sampling Comparison window contains the following columns:
- Class Name - Live Objects. Name of the class or live object.
- Live Bytes. Graphic display of the relative amount of memory currently occupied by the live object.
- Live Bytes. Memory size in bytes that is currently occupied by the live object.
- Live Objects. Exact difference between the number of live objects in the two snapshots.
You can perform the following actions in the memory comparison window.
- You can click a column header to sort the order that the results are displayed.
- You can load the source .java file of a class by right-clicking in
the row for the class and choosing Go To Source.
- You can filter the list by the class name by typing the filter criteria in the
Class Name Filter at the bottom of the window and clicking the filter icon
(
) to selecting a filter option.
Allocations Comparison
If Record object creation was selected for the profiling session,
the comparison provides details on the total number of instances.
The table in the Allocations Comparison window contains the following columns:
- Class Name - Allocated Objects. Name of the class or allocated object.
- Bytes Allocated. Graphic display of the relative amount of memory occupied by instances of the class.
- Bytes Allocated. Memory size in bytes occupied by the instances of the class.
- Objects Allocated. Number of all instances of the class.
Liveness Comparison
If Record both object creation and garbage collection was selected for the profiling session,
the comparison provides more detailed data on live instances.
The table in the Liveness Comparison window contains the following columns:
- Class Name - Allocated Objects. Name of the class or allocated object.
- Live Bytes. Graphic display of the relative amount of memory currently occupied by live instances of the class.
- Live Bytes. Memory size in bytes that is currently occupied by the live instances of the class.
- Live Objects. Number of current live instances of the class.
- Allocated Objects. Number of all instances of the class created since the application was started or since the results were last reset.
- Average Age. Average age in generations of live instances of the class.
- Generations. Number of different generations (garbage collections survived) of live instances of the class.
- See Also
- Taking a Snapshot
- Exploring Snapshots
- Analyzing Application Memory Usage
- About Profiling Results
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