Eyal, Yes, it is right to think of each Task attempt being one individual JVM running individually on any added Node. Multiple slots would mean multiple VMs in parallel as well. Yes, your use of reflection to build your objects will work just fine -- its all user-side java code that is executed.
On 30-Dec-2011, at 4:42 PM, Eyal Golan wrote: > Hi, > > I want to understand a basic concept in MR. > > If a mapper creates an instance of some class (using the 'new' operator), > then the created class exists ONCE in the VM of this node. > For each node. > Correct? > > Now, > what if instead of using the 'new' operator, the class is created using > reflection. > Is it valid in a MR? > Will only one instance of the created class be existing in that node? > > Thanks, > > > Eyal > > Eyal Golan > [email protected] > > Visit: http://jvdrums.sourceforge.net/ > LinkedIn: http://www.linkedin.com/in/egolan74 > Skype: egolan74 > > P Save a tree. Please don't print this e-mail unless it's really necessary >
