This document discusses common performance pitfalls in Java EE applications and provides recommendations to optimize performance. It covers optimizing servlet threads, database connections, object-relational mapping, rendering, state handling, and latency. Specific recommendations include reducing remote communication overhead, tuning database access and caching, minimizing web and AJAX requests, leveraging client and server caching, reducing file sizes and compressing content, and optimizing memory management and garbage collection.

1. Low Hanging Fruits in Optimizing J EE Performance Alois Reitbauer, dyna Trace Software

2. 1 n . . . Servlet Threads CPU 1 n . . . DB Conn. What‘s inside ?

3. a sample application architecture … … and common performance pitfalls O/R Access Rendering State Handling Latency Data Volume Comm. Behavior JavaScript Data Volume Comm. Behavior Memory and GC Memory and GC

4. What contributes to overall performance? Network Rendering Serialization Memory Usage Database Access

5. Remoting

6. Application Developers View Remote Communication How it works Client Application Stub Serialization Client Infrastructure Server Application Facade Deserialisation Server Infrastructure Networking Networking

7. Remote Communication What can go wrong

8. Avoid Protocol Overhead Reduce Interactions Create Data Locality Adjust Interfaces

9. Database

10. … looking inside Database Access Application Code Connection Pool Connection Result Set Application SQL TCP/IP Database O/R Mapping Layer Caching Layer Statement Connection Prepared Statement Prepared Statement . . .

11. Caching in the DB Layer Persistence Framework JDBC Layer Database Execution Plan Cache Prepared Statement Cache Cross Session Cache Session Caches Query Cache(s)

12. Reduce DB Calls Tune Loading Behavior Optimize for caching Define Proper Entities select … from a,b,c select … from b,c,a … join fetch ….

13. Web/AJAX

14. Web and AJAX What can go wrong Browser Server JavaScript Performance HTML Rendering Many AJAX/HTTP calls High Latency High Datavolume Thread-/ Connectionpools Network Database Access WebService/ Backend Calls Browser Browser

15. Caching on the Web Clients Server Cache per Client Server providing Caching Information Proxy Cache for Many Clients Serverside Data Cache

16. Reduce Files Use Caching Headers Compress Content Reduce State Date Expires E-Tag .js, css, png, …

17. Memory

18. Memory Management What can go wrong Short Lived Object in Tenured Space Large Temporary Object Complex Object Model

19. GC Configuration

20. Optimize Allocations Reduce Session Size Minimize GC Impact

21. alois.reitbauer@dynatrace.com Mail blog.dynatrace.com Blog AloisReitbauer Twitter