Best Practices in Developing Hig h Performance Java Applications A Perspective Keynote at Silicon India

1. Best Practices in Developing High Performance Java ApplicationsA PerspectiveKeynote at Silicon India Rajgopal Kishore Vice President and Global Head of BI & Analytics, HCL Technologies rkishore@hcl.in rkishore9@gmail.com

2. Agenda • Business Implication of System Performance • Understanding Performance Requirements • Sharing Some War Stories • Best Practices

3. Business Implications of System Performance • We all want a nice user experience • We won’t tolerate slow pages (we have options); lesser still any downtime • 500 ms slower = 20% drop in traffic (Google) • 100 ms slower = 1% drop in sales (Amazon) • Slower Warehouse management system – lower warehouse throughput! • Any downtime in a trading system - $m lost

4. What is Performance? Is a subset of NFR… • On-line applications - • Response time • Maintaining response time with increasing load – scalability • Throughput • Handles user expectations/frustration • Availability • Batch applications • Runs in the batch window – which is constantly shrinking! • Does not slow down other on-line work to an unacceptable level

5. Biggest Cause of Performance Failures.. • Not understanding performance requirements (implicit, explicit, real, or expectation) • Not setting expectations early enough • Not understanding and explaining trade-offs between performance and $ (infrastructure), and time

6. Performance Requirements Capture – Sample • The application will be optimized for high throughput. Traffic is to be tested for 250 concurrent users and 24/7 operations • All simple transactions will have a response time of less than 5 seconds. Complex transactions will have a response time of 15 seconds • The response time of all the pages would be less than 3 seconds

7. Consequently … • Performance requirements captured are insubstantial; Work pattern and user behavior is not understood • Infrastructure is suggested with out any basis • No performance benchmarking done till the system integration phase of the project • Benchmarking goals are not defined

8. What are Performance Requirements? - Multiple dimensions • Infrastructure model • Boxes, routers, IP splitters, CPUs, RAM, bandwidth • Transaction model • Transaction arrivals rates, think time, variation across the day • External transaction model • Any messages, file uploads • Data retention model • # years, hot, warm and cold areas, read-only or read-write

9. Some War Stories

10. Deathcare Major in the US … • 15000 users • Complex application • Low bandwidth network – 128K • 7 seconds response time needs – set after a discussion

11. Major Retailer … • Large and complex application for assortment planning • Board level visibility

12. Large fashion Retailer… • Big brand • Wanted a 2 second response time for a planning application

13. At a mid size Telecom company… • Need to “validate” capacity plan of their boxes for a MLM solution roll-out

14. Summarizing Some Best Practices in development high performance apps… What you will not get on the Internet

15. Best Practices … • Understand, set and control expectations. • Always attempt to understand real business need as opposed to articulated performance requirements • Big picture first – infrastructure capacity planning • Then optimize the application – create an app where the only bottleneck is the infrastructure …

16. Best Practices … • Abstraction is not good for performance …. Including Virtualization!!! • Do not use the same APIS for batch and on-line programs • Early stage performance prototyping….

17. Questions!