Hi Joe,
The reason for using the duplicate() function to copy data between the request and
application scopes is that creating a pointer to an application scope query in the
request scope, i.e.
<cflock scope="application" ...>
<cset request.myquery = application.myquery>
</cflock>
defeats the purpose of locking the application scope, since using the pointer created
in this example is still using the application scope directly and thus creates the
potential for server instability as a result of application scope race conditions.
You can test this in CF 5 : in the CF Administrator turn on "require locking" for the
application scope, then use the above example and reference the query outside the lock
-- CF Server responds with an error message indicating that the query contains
variables in the application scope and therefore cannot be referenced without an
active lock.
In some cases it's better to simply reference individual variables in a cflock since
you can't manipulate the pointer to a simple value directly in ColdFusion. If you need
the entire contents of a query however, it's often more efficient to go ahead and use
the extra memory in the request scope and let the CF Server's "garbage collection"
handle freeing that memory up after it finishes parsing the page.
Admittedly, I tend to err on the side of using more memory rather than going to the db
more often, etc... The reason I do this is because memory is generally less expensive
and easier to install than more processor speed, etc. Especially lately -- anyone else
notice the fire-sales on RAM this year? :)
Isaac
www.turnkey.to
954-776-0046
Original Message -----------------------
Hi Issac,
Your are right as well.."Right tool for the right Job". I wonder if it
would be a
better solution to "NOT Duplicate the Structure" like
<cflock type="readonly" timeout="20">
<cfset Request.MyReqQuery=Application.MyQuery> Note: No Duplicate or
StructCopy
</cflock>
There by only making referrence to Application scope like a POINTER since
the data doesnt need to manipulated and only stored/displayed.
Wouldnt this save memory space.. since u are not really creating a DEEP
Copy
into the 2nd structure(Request)?
Joe
Certified Advanced ColdFusion Developer
[EMAIL PROTECTED]
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