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https://issues.apache.org/jira/browse/HDFS-8287?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14733651#comment-14733651
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Tsz Wo Nicholas Sze commented on HDFS-8287:
-------------------------------------------
Some minor comments:
- We don't really need to declare the new class ParityGenerateTask. Just use
an anonymous class.
{code}
final byte[][] checkSumArrays =
doubleCellBuffer.getCheckSumArrays().clone();
completionService.submit(new Callable<Void>() {
@Override
public Void call() throws Exception {
encode(encoder, numDataBlocks, copiedBuffers);
synchronized (copiedBuffers) {
for (int i = numDataBlocks; i < numAllBlocks; i++) {
try {
writeParity(i, copiedBuffers[i], checkSumArrays[i]);
} catch (IOException e) {
LOG.warn("Caught exception ", e);
}
}
}
return null;
}
});
{code}
- Do we need to synchronize copiedBuffers? It is just a local variable.
- We should avoid copying arrays/buffers. Let do this improvement separately.
> DFSStripedOutputStream.writeChunk should not wait for writing parity
> ---------------------------------------------------------------------
>
> Key: HDFS-8287
> URL: https://issues.apache.org/jira/browse/HDFS-8287
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: hdfs-client
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Kai Sasaki
> Attachments: HDFS-8287-HDFS-7285.00.patch,
> HDFS-8287-HDFS-7285.01.patch, HDFS-8287-HDFS-7285.02.patch,
> HDFS-8287-HDFS-7285.03.patch, HDFS-8287-HDFS-7285.04.patch,
> HDFS-8287-HDFS-7285.05.patch, HDFS-8287-HDFS-7285.06.patch
>
>
> When a stripping cell is full, writeChunk computes and generates parity
> packets. It sequentially calls waitAndQueuePacket so that user client cannot
> continue to write data until it finishes.
> We should allow user client to continue writing instead but not blocking it
> when writing parity.
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