Thanks Neil -----Original Message----- From: Robertson-Ravo, Neil (RX) [mailto:[EMAIL PROTECTED] Sent: 07 September 2006 07:53 To: CF-Talk Subject: Re: Locking Theory
A race condition is a condition is where a value may be not what you expect when you get/set it. This is normally the case in say, application, server, and to a lesser degree session variables. So, you try and access value a, which you know to be "Jenny" - this is set at the server level. Problem is, Ben has went in at the same time to change this value to "Ben" just as you access it..this is a race condition. Cflock, ensures that this never happens, as Ben will only ever be able to chance value a to "Ben" after you have finished with it. Hth "This e-mail is from Reed Exhibitions (Oriel House, 26 The Quadrant, Richmond, Surrey, TW9 1DL, United Kingdom), a division of Reed Business, Registered in England, Number 678540. It contains information which is confidential and may also be privileged. It is for the exclusive use of the intended recipient(s). If you are not the intended recipient(s) please note that any form of distribution, copying or use of this communication or the information in it is strictly prohibited and may be unlawful. If you have received this communication in error please return it to the sender or call our switchboard on +44 (0) 20 89107910. The opinions expressed within this communication are not necessarily those expressed by Reed Exhibitions." Visit our website at http://www.reedexpo.com -----Original Message----- From: Jenny Gavin-Wear To: CF-Talk Sent: Thu Sep 07 07:43:30 2006 Subject: RE: Locking Theory Hi Ben, Could you explain the term "race condition" please? Jenny -----Original Message----- From: Ben Nadel [mailto:[EMAIL PROTECTED] Sent: 06 September 2006 23:30 To: CF-Talk Subject: RE: Locking Theory In my opinion, only use CFLock when you care if the race condition matters. Take setting SESSION values for instance. Let's say you have the following code: <cfset SESSION.FirstName = qUser.first_name /> This would NOT require a lock. Yes, it's shared data. Yes you could have conflicts. But the question is, does it matter? If a user has two pages that happen to run this code simultaneously, is there going to be a bad outcome if no locking? NOOOO. Both will set the appropriate value. Then take a session counter in the application: <cfset APPLICATION.SessionCount = ( APPLICATION.SessionCount + 1 ) /> Again, you are updating shared memory... But again, does it matter? Can this ever fire in such a way where it will get hurt? No. No matter what, sessions are going to be added. So the questions you need to ask yourself in this order are: 1. Is there a race condition? 2. Does the race condition matter? .......................... Ben Nadel www.bennadel.com Certified Advanced ColdFusion Developer Need Help? www.bennadel.com/ask-ben/ -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.405 / Virus Database: 268.12.1/440 - Release Date: 06/09/2006 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| Introducing the Fusion Authority Quarterly Update. 80 pages of hard-hitting, up-to-date ColdFusion information by your peers, delivered to your door four times a year. http://www.fusionauthority.com/quarterly Archive: http://www.houseoffusion.com/groups/CF-Talk/message.cfm/messageid:252328 Subscription: http://www.houseoffusion.com/groups/CF-Talk/subscribe.cfm Unsubscribe: http://www.houseoffusion.com/cf_lists/unsubscribe.cfm?user=11502.10531.4
