When you use custom tags to place exclusive locks around the session scope, it causes ColdFusion service issues, which affects all users within a shared environment. You can prevent these ColdFusion service issues by using a common fix we use to fine tune our code:

Use a variable scope to remove the memory being used by the session scope once the tag has completed it's necessary action.



We would be replacing all references of session to variables.LSess and copying the local copy of the structure back to the session scope.



If you have difficulty copying over structures in your local version to the session scope, you can duplicate each key under the local session structure over to the scope. Your final code would look similar to:

Can you explain why locking a session causes server-wide service issues?

Duplicating session scope for custom tags is generally unnecessary. In the past (pre-MX), session scope was generally duplicate()ed into the request scope for such issues, but those days are gone. MX+ sessions are thread safe, and accessing the session scope outside of a lock no longer causes server issues. Unless there is some sort of race condition that could occur, the locking suggested here is overhead (especially at 45 seconds). Also as a side note, the use of evaluate() is frowned upon, unless absolutely necessary.

That was essentially what I was getting at with my question. A session lock affects only the particular session in question on CFMX and the technique suggested here is completely unnecessary.

Also, as Nick pointed out, evaluate is poor practice and is completely unwarranted, as demonstrated in an earlier post by HMS itself. Also, the loop in the example is a list loop for some bizarre reason - instead, loop over the collection directly for this kind of thing. If for some reason you need to loop over a struct to copy every key, this would be the better way to do it:

<CFLOOP item="Key" collection="#variables.LSess#">
<CFSET Session[Key] =Duplicate(variables.LSess[Key])>
</CFLOOP>