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https://issues.apache.org/jira/browse/FLUME-3085?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16001532#comment-16001532
 ] 

ASF subversion and git services commented on FLUME-3085:
--------------------------------------------------------

Commit ed433ae1b12d40117ca3dca2ffd57389984ede72 in flume's branch 
refs/heads/trunk from [~denes]
[ https://git-wip-us.apache.org/repos/asf?p=flume.git;h=ed433ae ]

FLUME-3085. HDFS Sink can skip flushing some BucketWriters, might lead to data 
loss

This commit fixes the issue when in HDFSEventSink.process() a 
BucketWriter.append()
call threw a BucketClosedException then the newly created BucketWriter wasn't
flushed after the processing loop.

This closes #129

Reviewers: Attila Simon, Mike Percy

(Denes Arvay via Mike Percy)


> HDFS Sink can skip flushing some BucketWriters, might lead to data loss
> -----------------------------------------------------------------------
>
>                 Key: FLUME-3085
>                 URL: https://issues.apache.org/jira/browse/FLUME-3085
>             Project: Flume
>          Issue Type: Bug
>          Components: Sinks+Sources
>    Affects Versions: 1.7.0
>            Reporter: Denes Arvay
>            Assignee: Denes Arvay
>            Priority: Critical
>             Fix For: 1.8.0
>
>
> The {{HDFSEventSink.process()}} is already prepared for a rare race 
> condition, namely when the BucketWriter acquired in [line 
> 389|https://github.com/apache/flume/blob/trunk/flume-ng-sinks/flume-hdfs-sink/src/main/java/org/apache/flume/sink/hdfs/HDFSEventSink.java#L389]
>  gets closed by an other thread (e.g. because the {{idleTimeout}} or the 
> {{rollInterval}}) before the {{append()}} is called in [line 
> 406|https://github.com/apache/flume/blob/trunk/flume-ng-sinks/flume-hdfs-sink/src/main/java/org/apache/flume/sink/hdfs/HDFSEventSink.java#L406].
> If this is the case the {{BucketWriter.append()}} call throws a 
> {{BucketClosedException}} and the sink creates a new {{BucketWriter}} 
> instance and appends to it.
> But this newly created instance won't be added to the {{writers}} list, which 
> means that it won't be flushed after the processing loop finished: 
> https://github.com/apache/flume/blob/trunk/flume-ng-sinks/flume-hdfs-sink/src/main/java/org/apache/flume/sink/hdfs/HDFSEventSink.java#L429
> This has multiple consequences:
> - unflushed data might get lost
> - the {{BucketWriter}}'s {{idleAction}} won't be scheduled 
> (https://github.com/apache/flume/blob/trunk/flume-ng-sinks/flume-hdfs-sink/src/main/java/org/apache/flume/sink/hdfs/BucketWriter.java#L450),
>  which means that it won't be closed nor renamed if the idle timeout is the 
> only trigger for closing the file.



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