Out of memory (heap space) errors on job tracker

[David Rosenstrauch]

Our job tracker has been seizing up with Out of Memory (heap space) 
errors for the past 2 nights.  After the first night's crash, I doubled 
the heap space (from the default of 1GB) to 2GB before restarting the 
job.  After last night's crash I doubled it again to 4GB.

This all seems a bit puzzling to me.  I wouldn't have thought that the 
job tracker should require so much memory.  (The NameNode, yes, but not 
the job tracker.)

Just wondering if this behavior sounds reasonable, or if perhaps there 
might be a bigger problem at play here.  Anyone have any thoughts on the 
matter?

Thanks,

DR