Mailing-List: contact hdfs-issues-help@hadoop.apache.org; run by ezmlm
Precedence: bulk
Reply-To: hdfs-issues@hadoop.apache.org
Date: Thu, 9 Apr 2015 18:15:23 +0000 (UTC)
From: "Hudson (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
Message-ID: <JIRA.12787738.1427994915000.43147.1428603323917@Atlassian.JIRA>
In-Reply-To: <JIRA.12787738.1427994915000@Atlassian.JIRA>
References: <JIRA.12787738.1427994915000@Atlassian.JIRA>
 <JIRA.12787738.1427994915823@arcas>
Subject: [jira] [Commented] (HDFS-8046) Allow better control of
 getContentSummary
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 7bit


    [ https://issues.apache.org/jira/browse/HDFS-8046?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14487825#comment-14487825 ] 

Hudson commented on HDFS-8046:
------------------------------

FAILURE: Integrated in Hadoop-Mapreduce-trunk-Java8 #159 (See [https://builds.apache.org/job/Hadoop-Mapreduce-trunk-Java8/159/])
HDFS-8046. Allow better control of getContentSummary. Contributed by Kihwal Lee. (kihwal: rev 285b31e75e51ec8e3a796c2cb0208739368ca9b8)
* hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
* hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
* hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ContentSummaryComputationContext.java
* hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirectory.java
* hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirStatAndListingOp.java


> Allow better control of getContentSummary
> -----------------------------------------
>
>                 Key: HDFS-8046
>                 URL: https://issues.apache.org/jira/browse/HDFS-8046
>             Project: Hadoop HDFS
>          Issue Type: Bug
>            Reporter: Kihwal Lee
>            Assignee: Kihwal Lee
>             Fix For: 2.8.0
>
>         Attachments: HDFS-8046.v1.patch
>
>
> On busy clusters, users performing quota checks against a big directory structure can affect the namenode performance. It has become a lot better after HDFS-4995, but as clusters get bigger and busier, it is apparent that we need finer grain control to avoid long read lock causing throughput drop.
> Even with unfair namesystem lock setting, a long read lock (10s of milliseconds) can starve many readers and especially writers. So the locking duration should be reduced, which can be done by imposing a lower count-per-iteration limit in the existing implementation.  But HDFS-4995 came with a fixed amount of sleep between locks. This needs to be made configurable, so that {{getContentSummary()}} doesn't get exceedingly slow.


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