About ColdFusion threads
Threads are independent streams
of execution. Multiple threads on a page or CFC can execute simultaneously
and asynchronously, letting you perform asynchronous processing
in CFML.
Threads are useful for two broad types of activities:
Some typical uses for threads include the following examples:
An application that aggregates information from multiple
external sources, that takes significant time to respond, has the
code that gets information from each source in a separate thread.
This way, the application starts all requests quickly and has to
wait only until the last response is received, instead of having
to wait for a response to each request before the next request can
start. One example of such usage is an RSS or Atom feed aggregator.
A page that sends many mail messages runs the code that sends
the mail messages in a separate thread and doesn’t wait for it to
complete to continue processing. The thread that sends the mail
messages continues processing after the page-level processing is
completed and the application starts processing another page.
An application does maintenance of user data, such as using
update queries, deleting records, and so on, whenever a user logs
into the site. If the application does the maintenance in a separate
thread, the user gets an immediate response after logging in, without
having to wait for the updates to complete.
When ColdFusion processes a page, the page executes in a single
thread, called the page thread. The cfthread tag
lets you create additional threads that can process independently
of the page thread, and lets you synchronize thread processing,
for example, by having the page thread wait until threads that you create
complete their processing.
