AUTOMATED HEAPDUMP ANALYSIS FOR DEVELOPERS, TESTERS, AND SUPPORT EMPLOYEES

Transcription

1 AUTOMATED HEAPDUMP ANALYSIS FOR DEVELOPERS, TESTERS, AND SUPPORT EMPLOYEES Krum Tsvetkov Andreas Buchen TS-5729

2 Find memory leaks WITHOUT working with Memory Analyzer 2008 JavaOne SM Conference java.sun.com/javaone 2

3 Agenda Introduction Use Case Technical Support Use Case Development Use Case Testing Summary Q & A 2008 JavaOne SM Conference java.sun.com/javaone 3

4 Manual Memory Analysis Is Complex Requires experience with tools Requires expertise in the analyzed coding People with diverse skills are faced with memory problems 2008 JavaOne SM Conference java.sun.com/javaone 4

5 What Are the Goals of Memory Analyzer? Reduce complexity of handling memory issues Provide results of analysis, not only features to analyze Accommodate diverse skills and demands 2008 JavaOne SM Conference java.sun.com/javaone 5

6 Agenda Introduction Use Case Technical Support Use Case Development Use Case Testing Summary Q & A 2008 JavaOne SM Conference java.sun.com/javaone 6

7 Automated Problem Finding Helps Support Automatically detect and describe problem suspects Enable discovery of known solutions Facilitate the dispatching of new problems Collect details for in-depth analysis by the code experts 2008 JavaOne SM Conference java.sun.com/javaone 7

8 Automated Leak Suspects Discovery 2008 JavaOne SM Conference java.sun.com/javaone 8

9 What Happened Behind the Scenes? First, parsing of the heapdump is triggered Indexes for fast access to the data are generated A dominator tree of the object graph is computed It models the keep-alive dependences among the objects It helps to distinguish the biggest objects Analysis is triggered and the report is generated 2008 JavaOne SM Conference java.sun.com/javaone 9

10 Find Suspects in the Dominator Tree Leak Suspect Dominator Tree Treat very big objects in the dominator tree as suspects Accumulation Point A Significant drop in the retained sizes shows the accumulation point 2008 JavaOne SM Conference java.sun.com/javaone 10

11 Find Who Is Keeping The Suspect Alive Dominator Tree Shortest Path From A GC Root The chain of objects and references which keep the suspect alive 2008 JavaOne SM Conference java.sun.com/javaone 11

12 What Is the Suspect Keeping Alive? Dominator Tree The objects which have been accumulated 2008 JavaOne SM Conference java.sun.com/javaone 12

13 How Problem Suspects Are Found? Treat the biggest objects in the dominator tree as suspects A significant drop in the retained sizes shows the accumulation point 2008 JavaOne SM Conference java.sun.com/javaone 13

14 Heavy Request Analysis 2008 JavaOne SM Conference java.sun.com/javaone 14

15 How Are Request Details Extracted? If the Suspect is a Thread, then Thread Dominator Tree name Extract Activity Details <Java Local> Analyze the local variables and method parameters of the thread to determine its activity 2008 JavaOne SM Conference java.sun.com/javaone 15

16 Agenda Introduction Use Case Technical Support Use Case Development Use Case Testing Summary Q & A 2008 JavaOne SM Conference java.sun.com/javaone 16

17 A Developer-tailored Report Helps To Optimize Memory Footprint Help developers focus on their own component Give hints where footprint can be optimized Check for known anti-patterns Let developers implement their own checks 2008 JavaOne SM Conference java.sun.com/javaone 17

18 Component Footprint Analysis 2008 JavaOne SM Conference java.sun.com/javaone 18

19 Agenda Introduction Use Case Technical Support Use Case Development Use Case Testing Summary Q & A 2008 JavaOne SM Conference java.sun.com/javaone 19

20 What Can Be Done in the Testing Phase? Compare on a regular basis The retained sizes of a predefined list of components The sizes of some important objects Sessions Caches Regularly perform the report from the developers use case Regularly execute custom-specific reports that Check for unreleased resources (e.g. bundles, application loaders) Check for static fields referencing session data And so on 2008 JavaOne SM Conference java.sun.com/javaone 20

21 Agenda Introduction Use Case Technical Support Use Case Development Use Case Testing Summary Q & A 2008 JavaOne SM Conference java.sun.com/javaone 21

22 Summary Automated analysis of memory leaks and footprint Innovative features as building blocks SAP has contributed Memory Analyzer as open source 2008 JavaOne SM Conference java.sun.com/javaone 22

23 For More Information Memory Eclipse Memory Analyzer SAP Java+Memory+Analysis BLOGs: JavaOne SM Conference java.sun.com/javaone 23

24 Krum Tsvetkov Andreas Buchen TS JavaOne SM Conference java.sun.com/javaone 24