It is common in an error handler that you want to output all of the error details to the screen, a file, or an email. Therefore, the cfdump tag is commonly used for this; and, while this works well in development, it is not always the best practice on a production site because of the performance of the cfdump tag due to its use of reflection (Runtime type introspection).

A better performing alternative is to output the information you want directly from the Error/Exception struct within a 'cfoutput' tag. This can be done by looking up the Error structure or the cfcatch structure in the ColdFusion docs to see what is available and what values you might want to output:

You can also click here for an example CF custom tag that will give a similar error output as when using the cfdump tag on an error variable. Below is its usage:

In the error handler specified in your 'cferror' tag:
<cf_OutputError Error="#Error#" />
The above code would replace:
<cfdump var="#Error#" />
Or, in a cfcatch block:
   <cf_OutputCFCatch CFCatch="#CFCatch#" />