What is Oracle Webcache & how does it work?

Oracle AS webcache is a content-aware server accelerator or reverse proxy that improves the performance, scalability & availability of web sites that run on Oracle Application Server.

Oracle AS webcache stores frequently accessed URLs in the memory. Unlike legacy proxies that can handle only static objects, webcache caches static & dynamic generated content from one or more application web servers.

How does Reverse Proxy Web Caching Work?

1. A browser sends a request to a Web site named www.company.com:80
   
2. This request in turn generates a request to Domain Name System (DNS) for the IP address of the Web site
3. DNS returns the IP address of the load balancer for the site, that is,144.25.190.240
4. The browser sends the request for a Web page to the load balancer. In turn, the load balancer sends the request to OracleAS Web Cache server 144.25.190.241
5. If the requested content is in its cache, then OracleAS Web Cache sends the content directly to the browser. This is called a cache hit
6. If OracleAS Web Cache does not have the requested content or the content is stale or invalid, it hands the request off to application Web server 144.25.190.242.This is called a cache miss
7. The application Web server sends the content to OracleAS Web Cache
8. OracleAS Web Cache sends the content to the client and stores a copy of the page in cache