It is a potential race condition, but that doesn't automatically mean that a lock is needed. The data being updated is a list of forums and threads. It may be the case that it doesn't need to accurate to the millisecond. If I create a new thread and someone has a page view at the exact time I do the update, they might miss it, but they will see it on their next page view. A named exclusive lock would make sure that my request doesn't go through until my update is done, but the additional overhead might not be needed in this use case. I think that the worst situation would be a delete of a thread or forum and someone clicks on the link to the item that is in the process of being deleted. But that should just be a situation you'd want to catch anyway.
I'm a fan of locking anyway, so I would advocate for an exclusive named lock, but the best answer in this case is probably to try it with the locks, do some load testing, and find out what the overhead is. Then talk to the user base and see what the consensus is on whether the overhead is worth it. Judah Brian Kotek wrote: > This is the very definition of a race condition, and will require a lock to > ensure data consistency. > > On 8/22/07, Rick Root <[EMAIL PROTECTED]> wrote: >> Over the years, I've rarely used cflock for anything. I still don't >> fully understand when I should use it. >> >> Anyway, I'm concerned about scaling CFMBB... lots of application scoped >> stuff. >> >> For example, there are many places where I do this: >> >> <cfset application.forum.updateForumData()> >> >> Application.forum is an instance of forum.cfc ... all the >> updateForumData() does is run a bunch of queries to make sure the >> denormalized columns in the forums table (msgcount and lastpost) and >> in the threads table (lastpost) are up to date. This method is called >> each time a message or topic is posted or deleted, and each time a >> forum or conference is created or deleted. >> >> And everywhere I run it, I do this immediately after: >> >> <cfset application.qryForums = application.forum.getForums()> >> <cfset application.qryThreads = application.thread.getThreads()> >> >> This seems like a place where I might need locking ... but I'm really >> not sure =) >> >> In a very busy environment, this code could run a lot... imagine >> thousands of active users on a baseball team web site during the world >> series.. all posting new resposnes to the "official game thread"... >> where you might get 2000 responses or more during a 3 hour game. >> >> And yet your list of threads might get viewed 100 times per second >> during that time (which is why I'm putting the data - a relatively >> small amount of data.. just list of forums and list of threads) into >> the application scope. >> >> Comments? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| ColdFusion is delivering applications solutions at at top companies around the world in government. Find out how and where now http://www.adobe.com/cfusion/showcase/index.cfm?event=finder&productID=1522&loc=en_us Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:286914 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=89.70.4
