Heap Snapshot Option Dialog

     


  The heap snapshot options dialog is displayed each time before the actual heap snapshot is taken. The dialog has two tabs, grouping all overhead-related options on the second tab.
  If the Select recorded objects option is checked, the heap walker will restrict the heap snapshot to recorded objects only. In this way you can focus on the objects that have been created during a selected time span. If the option is unchecked, all objects on the heap will be shown (excluding any objects removed by the overhead options below).
  The overhead options are:
  • Remove unreferenced and weakly referenced objects
    If this option is checked, JProfiler will remove all objects from the heap that are not strongly referenced. These include:
    • unreferenced objects that are eligible for garbage collection
    • objects that are referenced only through soft, weak and phantom references
    • objects that are in the finalizer queue and will be garbage collected as soon as the finalizers have been run

    For strongly referenced objects, the heap walker will not display soft, weak and phantom references.

    This mode is preferable for memory leak detection, and is especially helpful to obtain useful information when showing the path to root for selected objects. Deselecting this option reduces the time for processing the heap snapshot and allows you to analyze the heap "as-is".

    Note: With Java >= 1.5.0 (JVMTI), unreferenced objects are not shown by the heap walker. The dynamic memory views like the all objects view and the recorded objects view can therefore show higher instance counts.

  • Calculate retained sizes
    Calculating retained sizes adds memory overhead while the heap snapshot is processed and can take some time for large heap snapshots. If you experience memory problems when taking heap snapshot or if you want the heap snapshot processing to take less time, you can deselect this option. In that case, no retained sizes will be available. Also, the biggest objects view will not be available.

    Retained sizes can only be calculated if the "Remove unreferenced and weakly referenced objects" is selected.

  • Record primitive data
    Note: This option is only visible when you profile with Java 1.4 (JVMPI) or with Java 1.6+ (JVMTI 1.1). With Java 1.5 (JVMTI 1.0), primitive data is not recorded.

    If this option is checked, the heap walker will record primitive data and display string values and values of primitive fields in the reference views.

    Deselecting this option will save memory and is advisable if you experience memory problems when taking heap snapshot. If primitive data is not recorded, it will be requested on demand in a live session, depending on whether the object still exists. The data may not be the same as at the time of the heap snapshot in that case. These on-demand requests only work for Java 1.5+. For Java 1.4, the outgoing references view will display N/A for primitive values.