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https://issues.apache.org/jira/browse/HADOOP-5859?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12713180#action_12713180
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Kan Zhang edited comment on HADOOP-5859 at 6/4/09 5:55 PM:
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> Unless the variable is declared as "volatile", right?
I just checked, the JDK6 implementation of LinkedList didn't declare the "size"
variable volatile. So Todd is right, a second thread may see a stale cached
value. In any case, this is a non-issue after my refactoring. In the refactored
code, all accesses to dataQueue or ackQueue are sync'ed on dataQueue lock.
was (Author: kzhang):
> Unless the variable is declared as "volatile", right?
I just checked, the JDK6 implementation of LinkedList didn't declare the "size"
variable volatile. So Todd is right, a second thread may see a stale cached
value (does anyone know how long the value will be cached by a thread, I hope
it's not forever :)). In any case, this is a non-issue after my refactoring. In
the refactored code, all accesses to dataQueue or ackQueue are sync'ed on
dataQueue lock.
> FindBugs : fix "wait() or sleep() with locks held" warnings in hdfs
> -------------------------------------------------------------------
>
> Key: HADOOP-5859
> URL: https://issues.apache.org/jira/browse/HADOOP-5859
> Project: Hadoop Core
> Issue Type: Bug
> Components: dfs
> Reporter: Kan Zhang
> Assignee: Kan Zhang
> Fix For: 0.21.0
>
> Attachments: 5859-21.patch, 5859-22.patch, 5859-26.patch,
> 5859-33.patch, 5859-35.patch, 5859-36.patch, 5859-38.patch, 5859-4.patch,
> 5859-40.patch, 5859-41.patch, 5859-5.patch, 5859-8.patch
>
>
> This JIRA fixes the following warnings:
> SWL org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.closeInternal() calls
> Thread.sleep() with a lock held
> TLW wait() with two locks held in
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.flushInternal()
> TLW wait() with two locks held in
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.flushInternal()
> TLW wait() with two locks held in
> org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.writeChunk(byte[], int, int,
> byte[])
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