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https://issues.apache.org/jira/browse/HADOOP-11542?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14312739#comment-14312739
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Zhe Zhang commented on HADOOP-11542:
------------------------------------
Thanks Kai for the updated patch.
Structures:
# Did you highlight the changes from HDFS-RAID's {{GaloisField}} class? Based
on your description, should I look for all {{ByteBuffer}} usage in your new
class, like the below?
{code}
+ /**
+ * A "bulk" version of the solveVandermondeSystem, using ByteBuffer.
+ */
+ public void solveVandermondeSystem(int[] x, ByteBuffer[] y,
+ int len, int dataLen) {
{code}
# Otherwise, the code structure looks good to me. However it's hard to fully
understand and verify the arithmetic logics so I think we should be careful to
check test results.
Nits:
# {{testCoding#usingDirectBuffer}} is not used?
# {{testCoding}} actually only tested lost data chunks; do we plan to test lost
parity chunks as well?
# In {{prepareInputChunksForDecoding}}, why are parity chunks put in front of
data chunks? Functionally it doesn't really matter, but it'd be better to have
a consistent ordering.
# {{TestJRSRawCoder#prepare}} looks it belongs to one of the base classes --
either {{TestCoderBase}} or {{TestRawCoderBase}}?
# "Please note this implementation doesn't outperform" -- let's remove this and
just say "Please always use the native implementation when possible."
# {{eraseDataFromChunk}} could used bulk put instead of putting individual
bytes.
# {{TestCoderBase#compareAndVerify}} could use {{deepEquals}} for nested arrays
# It doesn't actually matter in a loop condition, but would be better to unify
to {{i++}}.
{code}
for (int i = 0; i < erasedChunks.length; ++i) {
{code}
> Raw Reed-Solomon coder in pure Java
> -----------------------------------
>
> Key: HADOOP-11542
> URL: https://issues.apache.org/jira/browse/HADOOP-11542
> Project: Hadoop Common
> Issue Type: Sub-task
> Affects Versions: HDFS-EC
> Reporter: Kai Zheng
> Assignee: Kai Zheng
> Attachments: HADOOP-11542-v1.patch, HADOOP-11542-v2.patch,
> HADOOP-11542-v3.patch
>
>
> This will implement RS coder by porting existing codes in HDFS-RAID in the
> new codec and coder framework, which could be useful in case native support
> isn't available or convenient in some environments or platforms.
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