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https://issues.apache.org/jira/browse/HDFS-9494?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15066196#comment-15066196
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Tsz Wo Nicholas Sze commented on HDFS-9494:
-------------------------------------------

[~rakeshr], thanks for catching the bug.

For the latest patch, we should re-throw the ExecutionException as an 
IOException instead of printing a warning.  handleStreamerFailure may throw an 
exception when the failure is intolerable, i.e. when the number of remaining 
streamers is less than the number of data blocks.
{code}
+      } catch (ExecutionException ee) {
+        LOG.warn(
+            "Caught ExecutionException while waiting all streamer flush, ", 
ee);
+      }
{code}

> Parallel optimization of DFSStripedOutputStream#flushAllInternals( )
> --------------------------------------------------------------------
>
>                 Key: HDFS-9494
>                 URL: https://issues.apache.org/jira/browse/HDFS-9494
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>            Reporter: GAO Rui
>            Assignee: GAO Rui
>            Priority: Minor
>         Attachments: HDFS-9494-origin-trunk.00.patch, 
> HDFS-9494-origin-trunk.01.patch, HDFS-9494-origin-trunk.02.patch, 
> HDFS-9494-origin-trunk.03.patch
>
>
> Currently, in DFSStripedOutputStream#flushAllInternals( ), we trigger and 
> wait for flushInternal( ) in sequence. So the runtime flow is like:
> {code}
> Streamer0#flushInternal( )
> Streamer0#waitForAckedSeqno( )
> Streamer1#flushInternal( )
> Streamer1#waitForAckedSeqno( )
> …
> Streamer8#flushInternal( )
> Streamer8#waitForAckedSeqno( )
> {code}
> It could be better to trigger all the streamers to flushInternal( ) and
> wait for all of them to return from waitForAckedSeqno( ),  and then 
> flushAllInternals( ) returns.



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