Best Practices

The following are best-practice techniques for generating and controlling ColdFusion threads. Add these to your coding methodology to ensure better performance and thread safeness.

• Do not overuse ColdFusion threads; performance gains may be realized by leveraging the ColdFusion CFML gateway for some tasks.
  
  
• Keep thread names unique.
  
  
• Always specify a timeout when joining threads. Specify a timeout value that is less than the ColdFusion Administrator Timeout Request setting when joining threads to the page-level request.
  
  
• Properly scope all variables inside the thread body. Remember that unscoped variables default to the THREAD-LOCAL scope and are not accessible outside the thread.
  
  
• Use the thread’s name to access THREAD scope variables. Use CFTHREAD when accessing dynamically named threads.
  
  
• Use <cflock> to prevent potential deadlocks and race conditions between threads. Use the proper scope locks when threads access shared server resources: Server-, Application-, or Session-scoped variables. Use a Request scope lock when threads modify variables or Request-scoped variables. Use named locks when threads access shared resources such as Microsoft Exchange Server or FTP connections.
  
  
• Use the cfthread output metadata variable in page-level code to display thread-generated text.
  
  
• Use <cfabort>, <cfrethrow>, or <cfthrow> to send thread-level exceptions to the page-level code and properly set the threadName.Error and threadName.Status metadata variables.
  
  
• Use the theadName.Error metadata variable to handle thread-specific exceptions in external threads.
  
  
• Use <cflog> and <cftrace> to help track threads.
  
  
• Use the ColdFusion Administrator’s Maximum Number of Threads Available for CFTHREAD setting to control the pool size for concurrently running ColdFusion threads.
  
  
• Use the ColdFusion Server Monitor or the Server Monitor API to monitor and terminate hung threads.