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https://issues.apache.org/jira/browse/HDFS-7325?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14195124#comment-14195124
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Hadoop QA commented on HDFS-7325:
---------------------------------
{color:red}-1 overall{color}. Here are the results of testing the latest
attachment
http://issues.apache.org/jira/secure/attachment/12678981/HDFS-7325.001.patch
against trunk revision 67f13b5.
{color:green}+1 @author{color}. The patch does not contain any @author
tags.
{color:red}-1 tests included{color}. The patch doesn't appear to include
any new or modified tests.
Please justify why no new tests are needed for this
patch.
Also please list what manual steps were performed to
verify this patch.
{color:green}+1 javac{color}. The applied patch does not increase the
total number of javac compiler warnings.
{color:green}+1 javadoc{color}. There were no new javadoc warning messages.
{color:green}+1 eclipse:eclipse{color}. The patch built with
eclipse:eclipse.
{color:green}+1 findbugs{color}. The patch does not introduce any new
Findbugs (version 2.0.3) warnings.
{color:green}+1 release audit{color}. The applied patch does not increase
the total number of release audit warnings.
{color:red}-1 core tests{color}. The following test timeouts occurred in
hadoop-hdfs-project/hadoop-hdfs:
org.apache.hadoop.fs.TestEnhancedByteBufferAccess
{color:green}+1 contrib tests{color}. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-HDFS-Build/8626//testReport/
Console output: https://builds.apache.org/job/PreCommit-HDFS-Build/8626//console
This message is automatically generated.
> Prevent thundering herd problem in ByteArrayManager by using notify not
> notifyAll
> ---------------------------------------------------------------------------------
>
> Key: HDFS-7325
> URL: https://issues.apache.org/jira/browse/HDFS-7325
> Project: Hadoop HDFS
> Issue Type: Bug
> Affects Versions: 2.6.0
> Reporter: Colin Patrick McCabe
> Assignee: Colin Patrick McCabe
> Attachments: HDFS-7325.001.patch
>
>
> Currently ByteArrayManager wakes all waiting threads whenever a byte array is
> released and count == limit. However, only one thread can proceed. With a
> large number of waiters, this will cause a thundering herd problem. (See
> http://en.wikipedia.org/wiki/Thundering_herd_problem.) We should avoid this
> by only waking a single thread.
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