Hi Franco Maria, Try with: MAP_MEMORY=1500 JAVA_CHILD_OPTS=-Xmx1G -Dmapred.job.map.memory.mb="${MAP_MEMORY}" \ -Dmapred.map.child.java.opts="${JAVA_CHILD_OPTS}" \
Cheers, -- Gianmarco On Thu, Sep 13, 2012 at 11:01 PM, Franco Maria Nardini < francomaria.nard...@isti.cnr.it> wrote: > Hi all, > > I am running the PageRank code on single machine hadoop installation. > In particular, I am running the code using four workers on a graph of > 100.000 nodes. I am getting this exception: > > 012-09-13 22:54:38,379 INFO org.apache.hadoop.mapred.Task: > Communication exception: java.lang.OutOfMemoryError: GC overhead limit > exceeded > at > org.apache.hadoop.util.ProcfsBasedProcessTree.getProcessList(ProcfsBasedProcessTree.java:365) > at > org.apache.hadoop.util.ProcfsBasedProcessTree.getProcessTree(ProcfsBasedProcessTree.java:138) > at > org.apache.hadoop.util.LinuxResourceCalculatorPlugin.getProcResourceValues(LinuxResourceCalculatorPlugin.java:401) > at > org.apache.hadoop.mapred.Task.updateResourceCounters(Task.java:808) > at org.apache.hadoop.mapred.Task.updateCounters(Task.java:830) > at org.apache.hadoop.mapred.Task.access$600(Task.java:66) > at org.apache.hadoop.mapred.Task$TaskReporter.run(Task.java:666) > at java.lang.Thread.run(Thread.java:662) > > It's seems to be a problem related to communication stuff. Do I have > to specify or modify some options to hadoop to avoid this? > > Best, > > Franco Maria >