mapreduce memory issues

[Tamas Jambor]

Hi,

I came across a new problem with the mapreduce implementation. I am 
trying to optimize the cluster for this implemetation. But the problem 
is that in order to run 
RecommenderJob-UserVectorToCooccurrenceMapper-UserVectorToCooccurrenceReducer, 
I need to set -Xmx2048m, with a smaller value it fails the job. how come 
it needs so much memory? maybe there is a memory leak here? generally it 
is suggested to set -Xmx512m

the other problem setting it so high is that I have to reduce the number 
map/reduce jobs per node, otherwise the next job brings the whole 
cluster down.

Tamas