Deleting Client Variables Stored in the Registry
By default ColdFusion stores client variables in the registry. This can cause performance degradation in high-traffic sites as the registry will increase considerably in size, causing ColdFusion server instability. Allaire/Macromedia recommends storing client variables in an enterprise RDBMS. Here's the workaround:
Deleting Client Variables Stored in the Registry (Allaire/Macromedia Knowledge Base Article, March 8, 2001)