<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div>LOL! This is what I got when accessing those pastebins…</div><div><br></div><div><img height="1002" width="1350" apple-width="yes" apple-height="yes" id="c7a00285-91fb-4510-bec2-84499b1e5309" src="cid:9E4B5683-F6DC-4DEA-94DA-B014D07764EE"></div><br>On Jan 31, 2012, at 6:46 PM, Vladimir Blagojevic wrote:<br><br><blockquote type="cite">Response from Brent Douglas:<br><br>Hi Vladimir,<br><br>I'm not sure this is the same thing being discussed however if it is not I had intended to request this anyhow. When I looked into using infinispans's map reduce facility this is the the task I came up with:<br><br><a href="http://pastebin.com/7GGjVnVt">http://pastebin.com/7GGjVnVt</a><br><br>I would prefer to specify it as:<br><br>http://pastebin.com/HTSq3g66<br><br>I'm pretty sure this is the not intended use case but it distributes the creation of my reports which is what I want. It's not really a big deal for me as I can get around this limitation by creating a wrapper class such as in the first example but it would be nice if I did not have to. Is this a reasonable request?<br><br>Also, and this is probably just wrong, when I use this I bundle up the task and execute it via JMS. Would it be reasonable to make Collator extend Serializable?<br><br>Brent<br><br><br>On 12-01-30 11:47 AM, Vladimir Blagojevic wrote:<br><blockquote cite="mid:4F26AD6E.3030206@redhat.com" type="cite">Guys,<br><br>I was looking at this again recently and I still do not understand how combiner could have different interface than Reducer! Hadoop forces a user to implement combiner as a Reducer http://developer.yahoo.com/hadoop/tutorial/module4.html#functionality and http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/mapreduce/Job.html#setCombinerClass%28java.lang.Class%29 In addition, the original paper does not mention any change of types.<br><br>What we have admittedly done wrong is to apply Reducer on individual Mapper without checking if a reduce function is both commutative and associative! This can lead to problems: http://philippeadjiman.com/blog/2010/01/14/hadoop-tutorial-series-issue-4-to-use-or-not-to-use-a-combiner/<br><br>So yes, I am all for adding Combiner (it should do the optional reducer per mapper we do automatically now) but I do not see why we have to change the interface!<br><br><br>Regards,<br>Vladimir<br><br><br><br><br><div>_______________________________________________</div><div>infinispan-dev mailing list</div><br class="Apple-interchange-newline">infinispan-dev@lists.jboss.org<br>https://lists.jboss.org/mailman/listinfo/infinispan-dev<br></blockquote><br>_______________________________________________<br>infinispan-dev mailing list<br>infinispan-dev@lists.jboss.org<br>https://lists.jboss.org/mailman/listinfo/infinispan-dev<br></blockquote><br><div>--<br>Galder Zamarreño<br>Sr. Software Engineer<br>Infinispan, JBoss Cache<br></div><br></body></html>