From: Aaron Jackson [mailto:ajack...@pobox.com]
Sent: Tuesday, July 19, 2016 7:17 PM
To: user <user@spark.apache.org>
Subject: Heavy Stage Concentration - Ends With Failure
Hi,
I have a cluster with 15 nodes of which 5 are HDFS nodes. I kick off a job
that creates some 120 stages. Eventually, the active and pending stages reduce
down to a small bottleneck and it never fails... the tasks associated with the
10 (or so) running tasks are always allocated to the same executor on the same
host.
Sooner or later, it runs out of memory ... or some other resource. It falls
over and then they tasks are reallocated to another executor.
Why do we see such heavy concentration of tasks onto a single executor when
other executors are free? Were the tasks assigned to an executor when the job
was decomposed into stages?
