Java Performance Mistakes
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The document discusses common mistakes in Java performance, highlighting issues such as excessive SQL queries generated by Hibernate and inefficient data handling leading to long processing times. It emphasizes the need for proper caching strategies and improved collaboration between development and operations teams to address performance issues. Solutions proposed include custom logging mechanisms and measuring SQL executions more accurately to identify bottlenecks.
Java Performance Mistakes
- 1. Java Performance: Biggest Mistakes - More on http://blog.dynatrace.com - Dynatrace Free Trial: http://bit.ly/dttrial Andreas Grabner - @grabnerandi 1 @Dynatrace
- 2. And this is where I am from 2 @Dynatrace
- 3. 3 @Dynatrace
- 4. 4 @Dynatrace
- 5. Can you tell my age by looking at my first computer? 5 @Dynatrace
- 6. That’s why I ended up talking about performance 6 @Dynatrace
- 7. Nobody wants this … 7 @Dynatrace
- 8. 8 @Dynatrace
- 9. Nor this … 9 @Dynatrace
- 10. 10 @Dynatrace
- 11. As it leads to this … 11 @Dynatrace
- 12. The “War Room” Facebook – December 2012 12 @Dynatrace
- 13. And potentially to this … 13 @Dynatrace
- 14. 14 @Dynatrace
- 15. And this … 15 @Dynatrace
- 16. 16 @Dynatrace
- 17. And that’s why Business doesn’t like it either … 17 @Dynatrace
- 18. YES we know this 80%Dev Time in Bug Fixing $60B Defect Costs BUT ~80% of problems caused by ~20% patterns 18 @Dynatrace
- 19. 6 Situations on WHY this happened, HOW to avoid it 19 @Dynatrace
- 20. 20 @Dynatrace
- 21. “Blindly” (Re)use Existing Components 21 @Dynatrace
- 22. Requirement: We need a report 22 @Dynatrace
- 23. Using Hibernate results in 4k+ SQL Statements to display 3 items! Hibernate Executes 4k+ Statements Individual Execution VERY FAST But Total SUM takes 6s 23 @Dynatrace
- 24. 24 @Dynatrace
- 25. Not every Architect makes good decisions 25 @Dynatrace
- 26. Project: Online Room Reservation System • Symptoms • HTML takes between 60 and 120s to render • High GC Time • Assumptions • Bad GC Tuning • Probably bad Database Performance as rendering was simple 26 @Dynatrace
- 27. Developers built own monitoring void roomreservationReport(int roomid) { long startTime = System.currentTimeMillis(); Object data = loadDataForRoom(roomid); long dataLoadTime = System.currentTimeMillis() - startTime; generateReport(data, roomid); 27 @Dynatrace } Result: Avg. Data Load Time: 45s! DB Tool says: Avg. SQL Query: <1ms!
- 28. #1: Loading too much data 24889! Calls to the Database API! High CPU and High Memory Usage to keep all data in Memory 28 @Dynatrace
- 29. #2: On individual connections 12444! individual connections Classical N+1 Query Problem Individual SQL really <1ms 29 @Dynatrace
- 30. #3: Putting all data in temp Hashtable Lots of time spent in Hashtable.get Called from their Entity Objects 30 @Dynatrace
- 31. Lesson Learned • Custom Measuring • Was impacted by Garbage Collection • Just measured overall time but not # SQL Executions void roomreservationReport(int roomid) { long startTime = System.currentTimeMillis(); Object data = loadDataForRoom(roomid); long dataLoadTime = System.currentTimeMillis() - startTime; generateReport(data, roomid); } • Learn SQL and don’t use Hashtables as Workaround 31 @Dynatrace
- 32. 32 @Dynatrace
- 33. Implementation Flaws 33 @Dynatrace
- 34. Business Impact requires Action! 34 @Dynatrace
- 35. Solution: Cache to the RESCUE!! 35 @Dynatrace
- 36. Implementation and Rollout Implemented InMemory Cache Worked well in Load Testing 36 @Dynatrace
- 37. Result: Out of Memory Crashes!! Still crashes Fixed Version Deployed Problem fixed! 37 @Dynatrace
- 38. 38 @Dynatrace
- 39. Disconnected Teams 39 @Dynatrace
- 40. “Teamwork” between Dev and Ops SEV1 Problem in Production Need access to log files Where are they? Can’t get them Need to increase log level Can’t do! Can’t change config files in prod! 40 @Dynatrace
- 41. Solution: Implement a Custom “On Demand” Remote Logger 41 @Dynatrace
- 42. Implementation and Rollout Implemented Custom Logger Worked well in Load Testing 42 @Dynatrace
- 43. What happened? ~ 1Mio Lock Exceptions in 30 mins 43 @Dynatrace
- 44. Root Cause: A special WebSphere Setting! Log Service provides a synchronized log file across Log Service provides a synchronized ALL JVMs log file across ALL JVMs 44 @Dynatrace
- 45. 45 @Dynatrace
- 46. “Deployment” Gone Bad! 46 @Dynatrace
- 47. Test Environment Production Environment 8x slower 3x more SQL 47 @Dynatrace
- 48. Test Environment Production Environment Hibernate, Hibernate, Classloading, XML – The Key Classloading, XML – The Key Hotspots I/O for Web Requests Hotspots doesn’t even show up! That’s Normal: Having I/O for Web Request as main contributor 48 @Dynatrace
- 49. Top Contributor Class.getInterfaces Called from Hibernates FieldInterceptionHelper These calls all originate form thousands of calls to find item by code 49 @Dynatrace
- 50. Top Methods related to XML Processing Classloading is triggered through CustomMonnkey and the Xalan CustomMonkey and the Xalan Parser 50 @Dynatrace
- 51. 51 @Dynatrace
- 52. #Push without a Plan 52 @Dynatrace
- 53. Mobile Landing Page of Super Bowl Ad 434 Resources in total on that page: 230 JPEGs, 75 PNGs, 50 GIFs, … Total size of ~ 20MB 53 @Dynatrace
- 54. Fifa.com during Worldcup http://apmblog.compuware.com/2014/05/21/is-the-fifa-world-cup-website-ready-for-the-tournament/ 54 @Dynatrace
- 55. Waiting for Bug Reports 55 @Dynatrace
- 56. Look behind the scenes 56 @Dynatrace
- 57. 57 @Dynatrace
- 58. Performance Clinic: Bring Your Own App When: Thursday, December 18th Lunch Session: NOON – 3PM After Work Session: 4PM – 7PM Where: Dynatrace Office 404 Wyman Street, Waltham Register: http://bit.ly/onlineperfclinic 58 @Dynatrace
- 59. Quick Demo 59 @Dynatrace
- 60. 30 Days Dynatrace Free Trial • Get it here: http://bit.ly/dttrial • YouTube Tutorials: http://bit.ly/dttutorials • Live Q&A Sessions: http://bit.ly/onlineperfclinic • Contact me: [email protected] - @grabnerandi •Special Offer: • SaaS VIP Program: http://bit.ly/dtaasvip 60 @Dynatrace
- 61. Andreas Grabner Dynatrace Developer Advocate @grabnerandi http://blog.dynatrace.com 61 @Dynatrace
Editor's Notes
- #2: More detailed stories can also be found on our blog: http://blog.dynatrace.com All examples have been found using Dynatrace Free Trial – http://bit.ly/dttrial
- #3: Just a bit about myself: That’s where I am from: Austria!
- #4: Not the country with the kangaroos!
- #6: That was my first Amiga 500 which I got when I was 9 years old!
- #7: And that’s my professional background
- #8: But now lets get started …
- #19: Nobody likes to spend time in bugfixing
- #56: Stop waiting for problems to happen
- #57: Start looking behind the scenes