Identifying sources of memory retention

1. A method for identifying sources of memory retention in an executing application, the method comprising:

tracking a size for a set of objects over multiple time periods;

determining a period to be a growth period if the size for the set of objects increases above a previous maximum size, otherwise determining a period to be a non-growth period;

counting a number of growth periods within the multiple time periods;

flagging the set of objects if the number of growth periods is greater than a first threshold number of growth periods;

indicating a potential undesired object retention for the set of objects if the set of objects is flagged and the number of elapsed non-growth periods from the most recent growth period is less than or equal to a second threshold number, the second threshold number being a number of non-growth periods; and

locating a source of the memory retention by finding a cause of a resource consumption growth.

2. The method of claim 1 , further comprising limiting overhead to find the root cause by restricting a frequency at which said finding operation is performed for each identified set of objects.

3. The method of claim 2 , further comprising determining a context of the root cause after the set of objects is flagged as having unconstrained growth.

4. The method of claim 1 , further comprising determining a number of elapsed time periods from a most recent growth period.

5. The method of claim 1 , wherein tracking the size of the set of objects is performed using sampling.

6. The method of claim 5 , further comprising incrementing a counter when a new object is added to the set of objects by the application.

7. The method of claim 6 , further comprising determining what the time to track the size of the set of objects is when the counter reaches a multiple of a constant number.

8. The method of claim 1 , wherein the set of objects comprises objects aggregated by a collection class.

9. The method of claim 8 , further comprising declaration of a wrapper class which is a subclass of the collection class.

10. The method of claim 9 , wherein the wrapper class comprises additional fields including at least the number of growth periods, a maximum size observed, and a flag for indicating that the first threshold has been exceeded.

11. The method of claim 10 , wherein the additional fields further include a peak period identifier for determining if a number of elapsed periods from a peak period is less than or equal to a second threshold number.

12. The method of claim 1 , wherein the set of objects whose size is to be tracked comprises all objects of a particular type.

13. The method of claim 1 , wherein the set of objects comprises all objects reachable from a given object in the application.

14. The method of claim 1 , wherein the set of objects is specified by a user.

15. The method of claim 1 , wherein a length of each period is a fixed time period.

16. The method of claim 1 , wherein a length of each period is a variable time period in dependence on a configurable parameter.

17. The method of claim 16 , wherein the configurable parameter comprises an application load.

18. An apparatus configured with a processor for identifying sources of memory retention, the apparatus comprising:

processor-executable code configured to track a size for a set of objects over multiple periods;

processor-executable code configured to determine a period to be a growth period if the size for the set of objects increases above a previous maximum size, and otherwise indicating a period to be a non-growth period;

processor-executable code configured to count a number of growth periods over the multiple periods;

processor-executable code configured to flag the set of objects if the number of growth periods is greater than a first threshold number of growth periods;

processor-executable code configured to determine a number of elapsed non-growth periods from a most recent growth period; and

processor-executable code configured to indicate a potential memory leak in the set of objects if the set of objects is flagged and the number of elapsed non-growth periods from the most recent growth period is less than or equal to a second threshold number, the second threshold number being a number of non-growth periods;

processor-executable code to locate a source of the memory retention by finding a cause of a resource consumption growth.

19. A system configured with a processor for locating sources of memory retention, comprising:

means for observing a size for a set of objects over multiple periods;

means for designating a period as a growth period if the size of the set of objects increases above a previous maximum size, and otherwise designating a period as a non-growth period;

means for tracking a number of growth periods within the multiple time periods;

means for setting a flag corresponding to the set of objects if the number of growth periods is greater than a first threshold number of growth periods;

means for calculating a number of elapsed non-growth periods from a most recent growth period; and

means for reporting a potential memory leak in the set of objects if the set of objects is flagged and the number of elapsed non-growth periods from the most recent growth period is less than or equal to a second threshold number, the second threshold number being a number of non-growth periods; and

means for locating a source of the memory retention by finding a cause of a resource consumption growth.