Scalability

A true enterprise application must be scalable. The architecture of the SAS Information Delivery Portal uses a multi-tiered (also called n-tiered) distributed application model that is based on the Java 2 Platform. This allows the portal to scale to the requirements of even the largest enterprises.

One of the advantages of an n-tiered architecture is that it enables you to distribute your processing load across multiple processors. With the SAS Information Delivery Portal, your SAS programs and data access logic run on the back tier (also called the business tier) and are separated from the Web components that run on the middle tier (also called the Web tier). This not only distributes the workload, but it also allows you to take advantage of the SAS Multi-vendor Architecture (MVA) for your business logic that is implemented in the SAS 4GL. Because this code is portable, you can "right size" the business tier platform(s) to meet your needs.

The portal’s middle-tier components (comprised of a Web server that runs Java Servlets and JSPs) also operate in a multithreaded environment. This enables a single instance of a servlet to provide service for multiple clients by processing each request in a separate thread. Also, servlet technology provides even more throughput capacity because servlets do not have to be recompiled each time they are executed. And because Java technology is portable, you have a wide range of platforms available to choose from for this tier.

The SAS Information Delivery Portal also manages system resources wisely by pooling connections to Integrated Object Model (IOM) servers. When a client requests content that is located on an IOM server, the portal Web application uses a connection from the pool of connections to that server to retrieve the content rather than starting a new connection for each client that needs to access that server. When the request has been fulfilled, the connection is returned to the pool. This enables the middle tier to scale larger, and it also improves performance because a client does not have to wait for the connection to be established.

The portal also uses caching to achieve higher scalability. It caches on several levels. First, when it retrieves metadata for content from the enterprise directory, it saves this metadata for future accesses. The content itself is also cached on the file system of the middle tier. The portal manages these caches and ages out older information as required.

All of these features enable the SAS Information Delivery Portal to scale to the required level for your business.