MACROMEDIA COLDFUSION 4.5-ADMINISTRING COLDFUSION SERVER Manual page 158

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powerful client-side processing available via your browser. Some of these
technologies include Java Script, applets, Dynamic HTML, and ColdFusion's
WDDX components (for client-side form validation, for example). Well planned
use of these client technologies can reduce unnecessary trips to the server,
thereby minimizing performance degradation.
Business services — Represent the custom business logic and rules that the
application uses to perform calculations and application-specific functions. An
example of a business service would be an algorithm that automatically
calculates the shipping and handling charges for an order based on the total
cost of the order. In ColdFusion, this logic is contained within your CFML that
the ColdFusion Server processes and interprets. Depending on the nature of the
business and how often the business rules need to change, business logic can
be partitioned to sit on its own server for easier access that expedites frequent
logic modifications, or it can reside in stored procedures on the database server.
Data services — Refer to the interaction between the application and the
database in which the application stores and manipulates data. The way in
which an application manages data services is directly tied to the application's
performance capability. In short, accessing a database can be a costly endeavor
and can cause significant performance degradation depending on a variety of
factors. For example, the types of database drivers used for connections (native
vs. ODBC), the actual construction of SQL queries, the manner in which
database connections are pooled and maintained, and whether or not stored
procedures are implemented for frequent database access all directly impact
the application's performance.
The way in which architects and Web developers decide to partition and deploy these
core application services significantly affects the application's ability to scale. Although
your development efforts may no longer be burdened with developing, distributing,
customizing, and updating proprietary client software for your applications, the
ubiquitous graphical user interface (GUI) — the Web browser — presents new
interface issues and challenges. For example, you must ensure that your applications'
presentation remains performance-friendly. It should minimize the number and size
of graphic elements that must be downloaded to the client. Also, because not all
browsers are yet able to display all emerging technologies cleanly, such as Java applets
and frames, you should carefully evaluate their use in your applications.
Bear in mind these types of presentation guidelines to aid your applications'
performance and user experience, and be sure to plan and test for the lowest common
denominator that all browsers can accommodate.
Often, partitioning business services to a separate business logic application server
from the primary application server, if necessary, can yield better application
organization and easier maintenance. You can maximize your application's data
services by carefully constructing them and by ensuring that a separate database
server (in this case, a separate machine) is used to increase processor capacity for any
database transactions.
These are several of the most important topics you and the developers creating your
Web applications should consider early on. In doing so, you ensure that your Web
applications are designed and coded with scalability in mind.
Administering ColdFusion Server