tracker issue : CF-3946143

Problem Description:
When running cfcache on a site with a lot of concurrent traffic, it occasionally fails with an exception.
See other people's experience with the error at http://stackoverflow.com/questions/27412484/cache-already-exists-error-with-cfcache

Steps to Reproduce:
There is a code sample on the linked stackoverflow page.  In my case I had cfcache surrounding a code block, with memory storage.
Concurrent execution of the page is required.  The problem is a race condition so it's not always easy to produce.

Actual Result:
Message 	Cache erms_vuiTEMPLATE already exists 
StackTrace 	net.sf.ehcache.ObjectExistsException: Cache erms_vuiTEMPLATE already exists at net.sf.ehcache.CacheManager.addCache(CacheManager.java:1171) at coldfusion.tagext.io.cache.ehcache.GenericEhcache.createCache(GenericEhcache.java:516) at 
... (snipped for character count limit)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61) at java.lang.Thread.run(Thread.java:745) 

Expected Result:
Either there should be 1 cache miss and the other execution waits for the cache to be filled in, or two cache misses and both generate the content but only one is stored.  Either way no crash.


Any Workarounds:
Surround <CFCACHE> with <CFLOCK type="exclusive">.  Obviously this is heavy handed and harms performance more than necessary on multicore machines.

----------------------------- Additional Watson Details -----------------------------

Watson Bug ID:	3946143

External Customer Info:
External Company:  
External Customer Name: Stephen
External Customer Email:  
External Test Config: My Hardware and Environment details:

ColdFusion 10 Enterprise update 15.

Windows 2008 R2 64bit

Attachments:

1. September 29, 2015 00:00:00: 1_2015-04-14-2300-web_server_fetches_only.txt

Comments: