Yes...especially when speculative execution is NOT enabled. But we are
also seeing path problems when speculative execution is enabled. If it
is hanging in the map task my guess would be some type of map code. Are
you using regular expressions of anything similar? Also what is
processor load during the hang?
Dennis Kubes
Eyal Oren wrote:
Hi,
We're seeing some of our map tasks hanging indefinitely during
execution, and I just wanted to check if somebody maybe had seen similar
things (to figure out whether things are a hadoop problem or our problem).
We have a job that runs locally without problems. When pushed through
hadoop the job hangs randomly somewhere during map execution, it doesn't
progress but also doesn't report any exceptions (until it's killed after
its configured timeout). We thought it might be a concurrency problem,
but the same happens when running the job on only one node with only one
task running. Also, increasing java heap to 1GB did not help. Machine
is two-core Intel Xeon @1.86Ghz, with 2Gb of memory, hadoop 0.13.1 and
Java 1.6.0_02.
Has anyone maybe seen something similar? It's a bit hard to figure out
what's going on since we don't get any exceptions thrown.
-eyal
