Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hdfs-issues@hadoop.apache.org
Date: Sat, 29 Aug 2015 08:15:45 +0000 (UTC)
From: "Tsz Wo Nicholas Sze (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: <JIRA.12860485.1440835862000.201796.1440836145796@Atlassian.JIRA>
In-Reply-To: <JIRA.12860485.1440835862000@Atlassian.JIRA>
References: <JIRA.12860485.1440835862000@Atlassian.JIRA>
 <JIRA.12860485.1440835862839@arcas>
Subject: [jira] [Commented] (HDFS-8992) Balancer throws NPE
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HDFS-8992?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14721012#comment-14721012 ] 

Tsz Wo Nicholas Sze commented on HDFS-8992:
-------------------------------------------

Could you post the stack trace?

> Balancer throws NPE
> -------------------
>
>                 Key: HDFS-8992
>                 URL: https://issues.apache.org/jira/browse/HDFS-8992
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: balancer & mover
>    Affects Versions: 2.4.1
>            Reporter: He Xiaoqiao
>
> Balancer may throw NPE because the following {{if Statements}}
> {code:java|firstline=705}
>           synchronized (block) {
>             // update locations
>             for (String datanodeUuid : blk.getDatanodeUuids()) {
>               final BalancerDatanode d = datanodeMap.get(datanodeUuid);
>               if (datanode != null) { // not an unknown datanode
>                 block.addLocation(d);
>               }
>             }
>           }
> {code}
> Before moving block, Balancer divides into two step to get all DNs info & some blocks of DN from NN. Regarding one DN commission after {{getDatanodeReport}} then {{getBlockList}} and one block's target is above DN just right, It will throw NPE when dispatcher.


--
This message was sent by Atlassian JIRA
(v6.3.4#6332)