Integration of Database and Internet Technologies

The content of many web sites change frequently. Web site performance, including system up-time and user response time, is a key differentiation point among companies that are eager to reach, attract, and keep customers. Therefore, we develop solutions for integrating Internet services, business logic, and database technologies, and for improving end-to-end scalability of e-commerce systems (This work is done during my visit to NEC USA, CCRL; as a result, I only summarize the portion of the work which is already published).

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Web performance is a key differentiation among content providers. Snafus and slowdowns at major Web sites demonstrate the difficulty that companies face trying to scale to a large amount of Web traffic. One solution to this problem is to store Web content at server-side- and edge-caches for fast delivery to the end users. However, for many e-commerce sites, Web pages are created dynamically based on the current state of business processes, represented in application servers and databases. Since application servers, databases, Web servers, and caches are independent components, there is no efficient mechanism to make changes in the database content reflected to the cached Web pages. As a result, most application servers have to mark dynamically generated Web pages as non-cacheable. Thus, each user request for such a page results in additional delay.

We develop an architectural framework for enabling dynamic content caching for database-driven e-commerce sites. More specifically, we develop techniques for intelligently invalidating dynamically generated Web pages in the caches, thereby enabling caching of Web pages generated based on database contents. The solution achieves this by using a bi-layered approach which divides the problem into two components: sniffing or mapping the relationship between the Web pages and the underlying queries and, once the database is updated, invalidating the Web content dependent on queries that are affected by this update. Consequently, the proposed architecture consists of two independent components, a sniffer, which collects information about user requests and an invalidator, which removes cached pages that are affected by updates to the underlying data.

Another related issue is creation and maintenance of useable E-commerce sites. One important criteria of site usability is ease of navigation. To improcve the ease of navigation, we first have to identify the pages that are important, based on users interest and site structure. Such pages/nodesneeds to satisfy the following criteria:

• High connectivity so that users can navigate from these Web
  site map nodes to other nodes easily.
• The contents of these site map nodes need to be representative.

Thus, the nodes selected need to be both structural and content-wise representative. Therefore, we develop algorithms that can identify such representative nodes and use them to guide the user in site navigation.

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