[infinispan-issues] [JBoss JIRA] (ISPN-3999) Invoke reducer while intermediate values are being collected

Invoke reducer while intermediate values are being collected ------------------------------------------------------------ Key: ISPN-3999 URL: https://issues.jboss.org/browse/ISPN-3999 Project: Infinispan Issue Type: Enhancement Reporter: Vladimir Blagojevic Assignee: Mircea Markus Currently in intermediate phase [1] as values for every KOut are being collected/grouped in the cluster we simply add every VOut to the list of values key by KOut. In reducer phase we then send a reducer function that gets invoked on List<VOut> and reduces those values into single VOut. However, this could be suboptimal as we can invoke reducer function as every VOut gets grouped rather than wait for all VOut values to be collected and then invoke reducer. However, reduce function could potentially take a lot of time to execute even for one value thus causing prolonged locking and congestions. We should implement this enhancement and do thorough performance measurements. This feature should be have an API setting in MapReduceTask. Sanne Grinovero gets the credit for this idea. [1] http://blog.infinispan.org/2012/07/mapreduce-improvements-in-infinispan.html