5.5 The Oracle 9 Internet Application Server
5.5 The Oracle 9 Internet Application Server The Oracle 9iAS is an excellent example of both an application server that is available to developers to develop their own applications and a platform for Oracle applications. The Oracle 9iAS is designed to be an environment in which multiple applications can be integrated into one portal . Users are able to access data from browsers or wireless devices to view both unstructured and structured data. Figure 5.12 presents the structure of the Oracle 9iAS. Figure 5.12. Oracle 9iAS. 5.5.1 APPLICATION SERVER CACHELet's begin by relating the features of the Oracle 9iAS with the discussion in the previous section. In Figure 5.12 we note that there is not only a cache between the application server and the database, but between the Web server and the client. In a sense, the application server is surrounded by cache. The Web cache stores both static and dynamic HTML pages. If a page requested by a user is in the Web cache, it is sent directly from the Web cache. Of course, the Web cache cannot store all the pages for a particular Web site. The cache must be cleared of old or outdated pages. The Oracle 9iAS uses a heuristic algorithm to determine which pages need to be refreshed from the Web server. The algorithm uses two variables for every page. The first is a priority variable to establish how important any change may be to a Web page. The second is a validity flag to signal when the data is outdated or invalid and needs refreshing. The first may indicate a cosmetic change, such as a graphic image, font, or color layout. While these changes are nice, they are not critical to the correctness of the data on the page. Consequently, we may give these pages a low priority. We would like to see the change, but it is not critical that it occur immediately. The second flag, when checked, notes that the data on the Web page is no longer valid and must to be updated. For example, we may have a Web site that provides information about our organization along with our price list. At some point in time, we change our company logo along with several prices in the price list. When a user comes to our Web site, we would not want the entire cache purged and repopulated from the Web server. This could quite possibly bring down the Web server. Instead, when a page is accessed, we check to see if the page is valid. If the current cache page is invalid, it is deleted from cache and a newer , valid page is requested from the Web server. If the page is valid, but has a low update priority, the activity on the Web server is checked to see if there are pages being downloaded that are of a higher priority. If the Web server is too busy, the current cached page is sent to the client. If the Web server is available, a new page is retrieved. Consider what this means in relation to IEBI. The application server builds user-requested pages, storing them in the Web cache upon creation. As the user drills down, the new pages are also loaded into the cache. As we proceed back up through the aggregated data, as users quite often do, the cached pages are sent to the user, eliminating the need to access the Web server. The application server also maintains a database cache, which sits between the application and database servers and maintains complete database tables so that queries can be processed completely on the application server. This is very important to IEBI. For example, Oracle provides pre-aggregation of data through materialized views and summation tables. We can cache the materialized views in the database cache on the application server. The majority of queries are fulfilled by the application server, freeing the data warehouse server resources to meet requests that are more demanding. Only when the user requests data that is down to the deepest level of detail do we need to perform a query against the actual data warehouse database. 5.5.2 CUSTOMIZABLE PORTAL PAGESAnother important aspect of the Oracle9iAS is the ability to create an information portal. We discussed the concept of information anarchy, an environment where there is an explosion of information systems and no centralized control of the data. We see symptoms of that anarchy in the Internet-enabled information infrastructure of many of today's organizations. There is a multitude of Web sites and Internet applications throughout the organization. Finding a specific piece of information is near impossible because each department has its own site. Even when you know where to find the information, every time you go to a different Web site, you have to log on to yet another system. Now consider the needs of the decision maker. He or she may require reports on a daily basis. Perhaps the decision maker uses a multidimensional analysis tool. In addition, the C-level executive may be interested in viewing the company's Balanced Scorecard. A manufacturing executive may be interested in analyzing production costs using the Activity Based Management tools or in doing profitability analysis on a particular region or product line. Even in the best of situations, where the Web sites to access these applications are bookmarked in the user's browser, they would still require separate logons . This is where the portal comes into play. The term portal is freely bantered about in the marketplace . A portal establishes a single, personalized Web site from which the user can access any number of applications. The Oracle9iAS provides an extensible framework for bringing together applications and business information into a single personalized Web page; it is in effect a single point of access to information. Note that from this one page the strategist has access to a balanced scorecard application, reports, alerts, email, multidimensional analysis tools, and activity-based management systems. What is important about this environment is that to the user, this is simply his or her Web page. The fact that he or she is accessing multiple applications in different parts of the world is invisible to the user. He or she may have no concept of which applications are providing which information. It is all one integrated environment. How does the Oracle9iAS make this happen? Portlets! As we noted, the portal is a framework. Into this framework fit the portlets, reusable interface components that provide access to Web-based resources. These resources can include any Web page, application, BI report, syndicated content feed, hosted software service, or resource. Companies can create their own portlets or acquire third-party portlets from such companies as Cognos and Business Objects. What is key is that the user is provided a seamless environment or console from which the organization's environment can be analyzed . We need to emphasize this point, not only in relation to the Oracle9iAS, but to IEBI in general. It is critical to the success of IEBI that the decision makers interact with the data. It is up to the architect of the IEBI system to lower whatever barriers there are between decision makers and the strategic information they need to do their jobs. With the IEBI portal, the decision maker has the complete complement of BI tools at his or her disposal. If we were to play this out in a typical business scenario, the decision maker may note on his site that a key performance indicator in the balanced scorecard is out of range. Perhaps profitability for a particular product is down. From this page, the decision maker goes into the activity-based management tool and determines that the cost to manufacture the product has risen dramatically. In tracing through the activity costs, he notes that the capacity of a particular manufacturing facility has been exceeded, forcing production to run an additional shift. The decision maker then refers to the multidimensional analysis tool, where he discovers excess capacity at another nearby facility. He then sends an email to the production manager concerning what has been discovered . As far as the user is concerned , this was all done from one application, the IEBI portal. In reality, the decision maker has accessed five different applications. The important part is that we have given the decision maker a way to interact with the data.  |
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