One of the most exciting recent developments in Web page technology is the ability to develop dynamic pages — Web pages that are not assembled until the client requests them. Dynamic pages can display the most current data available and can be tailored to clients' preferences. The power of dynamic pages is likely to increase their use on intranets and on the Internet.
Recent experience has shown that applications written for the Common Gateway Interface (CGI), the most popular dynamic Web page interface, severely degrade performance on Windows NT servers. The performance overhead of some CGI applications can cause both memory and processor bottlenecks. These bottlenecks are far less likely on applications written for the Internet Server Application Programming Interface (ISAPI). Therefore, it is important to understand how CGI and ISAPI applications generate dynamic pages, and how to measure and minimize their overhead.
This chapter covers the following sections:
"CGI and ISAPI Interfaces." An overview of the supported interfaces for generating dynamic pages on Windows NT. This section explains how CGI and ISAPI run on Windows NT and why they perform differently.
"Monitoring Client Requests for Dynamic Pages." Guidelines for using Performance Monitor to monitor client requests for pages generated by CGI and ISAPI. Requests are the primary measure of activity of applications that generate dynamic pages.
"Monitoring Servers Running CGI and ISAPI Applications." Suggests methods of monitoring the overall performance of servers running CGI and ISAPI applications using Performance Monitor and Microsoft Web Capacity Analysis Tool (WCAT).
"Tracking CGI Processes." Guidelines for using Process Monitor and the Processes Tab in Task Manager to track CGI request processes.
"Capacity Planning to Support CGI Applications." Suggests additions to an Internet Information Server (IIS) server configuration to enable you to support CGI applications and minimize their performance overhead.
These topics build on information presented in Chapter 5, "Monitoring Virtual Memory" and Chapter 6, "Preventing Processor Bottlenecks." For more information about CGI and ISAPI interfaces, see the online Windows NT Microsoft Internet Information Server Installation and Administration Guide.