I am trying lock block on page test.cfm and below is code written on page.

<cfscript>
writeOutput("Before lock at #now()#");
lock name="threadlock" timeout="3" type="exclusive"
{
    writeOutput("<br/>started at #now()#");
    thread action="sleep"  duration="10000";
    writeOutput("<br/>ended at #now()#");
}
writeOutput("<br/>After lock at #now()#");
</cfscript>

assuming my url for page is http://localhost.local/test.cfm and running it on browser in two different tabs. I was expecting one of the url will throw timeout error after 3 second since another url lock it atleast for 10 seconds due to thread sleep. Surprisingly I do not get any timeout error rather second page call run after 10 seconds as first call finish execution.

But I am appending some url parameter (e.g. http://localhost.local/test.cfm?q=1) will throw error. Also I am calling same url in different browser then one of the call will throw timeout issue.

Is lock based on session and url?

Update Here is output for two different cases:

Case 1:

TAB1 Url: http://localhost.local/test/test.cfm

 Before lock at {ts '2013-10-18 09:21:35'} 
 started at {ts '2013-10-18 09:21:35'} 
 ended at {ts '2013-10-18 09:21:45'} 
 After lock at {ts '2013-10-18 09:21:45'}

TAB2 Url: http://localhost.local/test/test.cfm

Before lock at {ts '2013-10-18 09:21:45'} 
started at {ts '2013-10-18 09:21:45'}
ended at {ts '2013-10-18 09:21:55'} 
After lock at {ts '2013-10-18 09:21:55'}

Case 2:

TAB1 Url: http://localhost.local/test/test.cfm

 Before lock at {ts '2013-10-18 09:27:18'} 
 started at {ts '2013-10-18 09:27:18'} 
 ended at {ts '2013-10-18 09:27:28'} 
 After lock at {ts '2013-10-18 09:27:28'}

TAB2 Url: http://localhost.local/test/test.cfm? (Added ? at the end)

Before lock at {ts '2013-10-18 09:27:20'} 
A timeout occurred while attempting to lock threadlock.
The error occurred in C:/inetpub/wwwroot/test/test.cfm: line 13
11 : 
12 : <cfoutput>Before lock at #now()#</cfoutput>
13 : <cflock name="threadlock" timeout="3" type="exclusive">
14 :    <cfoutput><br/>started at #now()#</cfoutput>    
15 :    <cfthread action="sleep"  duration="10000"/> 
...

Result for case 2 as expected.

For case 1, strange thing I just noticed is tab 2 output "Before lock at {ts '2013-10-18 09:21:45'} indicates that whole request start after 10 seconds (means after the complete execution of first tab) when I have fired it in second URL just after 2 seconds of first tabs.