Heap space error during copy from maptask to reduce task

http://stackoverflow.com/questions/19298357/out-of-memory-error-in-mapreduce-shuffle-phase

I've described the problem on stackoverflow as well. It contains a link to another JIRA: http://hadoop-common.472056.n3.nabble.com/Shuffle-In-Memory-OutOfMemoryError-td433197.html

My errors are completely the same: out of memory error when mapred.job.shuffle.input.buffer.percent = 0.7, the program does work when I put it to 0.2, does this mean the original JIRA was not resolved?

Does anybody have an idea whether this is a mapreduce issue or is it a misconfiguration from my part?