Using tracing
As
its name indicates, the cftrace tag is designed to
help you trace the execution of your application. It can help you
do any of several things:
You can time the execution of a tag or code section.
This capability is useful for tags and operations that can take
substantial processing time. Typical candidates include all ColdFusion
tags that access external resources, including cfquery, cfldap, cfftp, cffile, and so on. To time
execution of any tag or code block, call the cftrace tag
before and after the code you want to time.
You can display the values of internal variables, including
data structures. For example, you can display the raw results of
a database query.
You can display an intermediate value of a variable. For
example, you could use this tag to display the contents of a raw
string value before you use string functions to select a substring
or format it.
You can display and log processing progress. For example,
you can place a cftrace call at the head of pages
in your application or before critical tags or calls to critical
functions. (Doing this could result in massive log files in a complex
application, so use this technique with care.)
If a page has many nested cfif and cfelseif tags you can place cftrace tags
in each conditional block to trace the execution flow. When you
do this, use the condition variable in the message or var attribute.
If you find that the ColdFusion server is hanging, and you
suspect a particular block of code (or call to a cfx tag, COM object,
or other third-party component), you can place a cftrace tag
before and after the suspect code, to log entry and exit.
