Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hdfs-issues@hadoop.apache.org
Date: Fri, 14 Aug 2015 10:48:45 +0000 (UTC)
From: "Walter Su (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: <JIRA.12856122.1439547863000.66666.1439549325660@Atlassian.JIRA>
In-Reply-To: <JIRA.12856122.1439547863000@Atlassian.JIRA>
References: <JIRA.12856122.1439547863000@Atlassian.JIRA>
 <JIRA.12856122.1439547863841@arcas>
Subject: [jira] [Updated] (HDFS-8896) DataNode object isn't GCed when
 shutdown, because it has GC root in ShutdownHookManager
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


     [ https://issues.apache.org/jira/browse/HDFS-8896?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Walter Su updated HDFS-8896:
----------------------------
    Status: Patch Available  (was: Open)

> DataNode object isn't GCed when shutdown, because it has GC root in ShutdownHookManager
> ---------------------------------------------------------------------------------------
>
>                 Key: HDFS-8896
>                 URL: https://issues.apache.org/jira/browse/HDFS-8896
>             Project: Hadoop HDFS
>          Issue Type: Bug
>          Components: test
>            Reporter: Walter Su
>            Assignee: Walter Su
>            Priority: Minor
>         Attachments: HDFS-8896.01.patch, screenshot_1.PNG, screenshot_2.PNG
>
>
> The anonymous {{Thread}} object created in {{ShutdownHookManager}} is a GC root.
> screenshot_1 shows how DN object be traced to the GC root.
> It's not a problem in production.
> It's a problem in test, especially when MiniDFSCluster starts/shutdowns many DNs, which could cause {{OutOfMemoryError}}.
> screenshot_2 shows many DN objects are not GCed when run the test of HDFS-8838.


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