[
https://issues.apache.org/jira/browse/HIVE-14739?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15485485#comment-15485485
]
Chris Nauroth commented on HIVE-14739:
--------------------------------------
[~prasanth_j], thank you for sharing this patch. It's interesting for me to
see that Hive appears to have forked its own copy of {{ShutdownHookManager}}
from Hadoop. I don't know the background on this. The code is similar, but
not identical, between the two codebases. Perhaps that's because the Hive
version was not updated to match recent changes in Hadoop, like HADOOP-12950.
In order to fully prevent deadlocks between different shutdown hooks, there
really needs to be a single {{ShutdownHookManager}} in the process. If Hadoop
and Hive each have their own implementation, and a Hive process instantiates
one of each and registers different shutdown hooks with each one, then there
will be 2 threads executing different shutdown hooks concurrently, which could
still cause a deadlock.
Would it make sense to eliminate the forked {{ShutdownHookManager}} class in
Hive and instead rely completely on using the one from Hadoop?
Also, a minor nit: maybe all calls to {{new Thread()}} could be converted to
{{new Runnable()}}. The {{Runnable}} interface is sufficient, and it won't
make use of any additional functionality provided by the {{Thread}}
implementation.
> Replace runnables directly added to runtime shutdown hooks to avoid deadlock
> ----------------------------------------------------------------------------
>
> Key: HIVE-14739
> URL: https://issues.apache.org/jira/browse/HIVE-14739
> Project: Hive
> Issue Type: Bug
> Affects Versions: 2.2.0
> Reporter: Deepesh Khandelwal
> Assignee: Prasanth Jayachandran
> Attachments: HIVE-14739.1.patch
>
>
> [~deepesh] reported that a deadlock can occur when running queries through
> hive cli. [~cnauroth] analyzed it and reported that hive adds shutdown hooks
> directly to java Runtime which may execute in non-deterministic order causing
> deadlocks with hadoop's shutdown hooks. In one case, hadoop shutdown locked
> FileSystem#Cache and FileSystem.close whereas hive shutdown hook locked
> FileSystem.close and FileSystem#Cache order causing a deadlock.
> Hive and Hadoop has ShutdownHookManager that runs the shutdown hooks in
> deterministic order based on priority. We should use that to avoid deadlock
> throughout the code.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
