Tuesday

Tuning and optimization J2EE web application for HighLoad

Last few months we are developing a portal for 3rd largest bank in Europe. Unique visitor of the bank grows more than 1 million visitor in a day. The main non functional requirements of the project is the high availability of the portal and giving high through output. One of the main feature of the portal is to giving user to customize their pages with widgets and provide different services for targeted auditory. After a long discussion and analysis, bank decided to use java based engine to build up the portal and we have got the following stack:
1) Java 1.7_47
2) IBM WEBSphere 8.5 as Application server
3) Nginx as web server
4) Alteon as load balancer
5) Oracle 11gR2 as DataBase
6) SOLR for content search
Main challenge for us to supported legacy browser such as IE8, opera 12 e.t.c and one portal for all device (desktop, smart phone and tablet pc). Java based portal engine generated a lot of java script which didn't give us very good performance. For these above reasons we decided to use hybrid method of page rendering (server side (jsp) + client side (java script)) and rest service for business functionality. We eliminate of implementing any business logic in DataBase because, RDBMS is not suitable for scaling and minimize the network roundtrip. Here is our main design decision:
1) Implementing business logic through Rest service in application server
2) Serving all the static content from web server
3) Cashing is as much as possible in every layer
4) Hybrid method of page rendering (server side (jsp) + client side (java script))
Now it's the time for describe briefly what we have done in every layer, most of all steps are well known and i would like to summarize it in one place:

1) Web server optimization (nginx):
- Gzip compression level 6 for xml, json, css, html e.t.c
- Cache control Http header for 3 days
- Cache control for java script
- Etag
2) Client side optimization:
- Minify java script and CSS
- Minimize http request from browser to server. At the beginning we have more than 150 http request from browser to server. It should be remember that modern browser can make 7-8 request at a time to one domain
- Optimize every images (lossless)
- Using CSS sprite
- Aggregate CSS and JS in few files
- Minify Html
3) Server side (backend) optimization:
- Caching every rest response
- using distributive EhCache
- Hibernate + MyBatis second level Cache
- Optimize Connection Pool for database in IBM WAS
- Optimize heap size and GC policy for JVM in IBM WAS
- Optimize thread pool size in IBM WAS
- Optimize session management for IBM WAS
- Scheduler to drop long running and hanged SQL connection from IBM WAS (There is a bug in IBM WAS with connection pool)
4) Database optimization
- Using result cache for Data dictionary
- Move Data dictionary to Oracle KEEP POOL

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