Performance

Question 1

General OutOfMemoryCause

Answer 1

General OutOfMemoryCause

1. Memory leak
2. Memory Over Consumption

How to Investigate where is wrong?

1. attach Jprofiler - the ones survive most generations/occupy most memory
2. take memory dump
   - XX heapdumpuro memoryerror I-XXheapdumpurofmemoryerrorPath

Strategy to resolve?

1. NFT stress testing for application
2. Bug - equals() not overriden
3. Using batch rather than load everything in one go
4. Trade-off between re-compute and caching (Keep only necessary data in caching, most costly to compute, long SQL loading)
5. Increase JVM memory

Object allocate rate issue?
Latency - how long to process 1 request
Throughput - how many request my app can handle at peak time