Race condition while launching task cleanup attempt.
----------------------------------------------------
Key: MAPREDUCE-1475
URL: https://issues.apache.org/jira/browse/MAPREDUCE-1475
Project: Hadoop Map/Reduce
Issue Type: Bug
Components: tasktracker
Affects Versions: 0.20.1
Reporter: Amareshwari Sriramadasu
We found a race condition while launching task cleanup attempt on a TaskTracker
which would eat up a slot.
The scenario is the following:
The main attempt is killed by TaskTracker because it was a speculative attempt.
Cleanup attempt is launched on the same tracker. Cleanup attempt occupied the
slot and is about to start. But, there was a pending RPC: done() from earlier
attempt in the RPC queue. Before the cleanup attempt could be launched,
TaskTracker processed the rpc from earlier attempt and made the state of the
cleanup attempt as KILLED. Launcher did not launch it because it was already
KILLED. But, the rpc done() failed with NullPointerException because of false
state. In summary, the slot was occupied by the cleanup attempt which could not
be launched. And the slot was never released.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
