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https://issues.apache.org/jira/browse/HDFS-8901?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15338872#comment-15338872
]
Kai Zheng commented on HDFS-8901:
---------------------------------
Thanks Bo for the update, and fixing of the test failure.
The fix by implementing the {{read(ByteBuffer buf)}} method looks good, but I
wonder if we could remove the long deprecated class entirely at all. Will raise
this separately.
{code}
diff --git
a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/impl/BlockReaderRemote.java
b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/impl/BlockReaderRemote.java
index 22d4e23..d7c5da9 100644
---
a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/impl/BlockReaderRemote.java
+++
b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/client/impl/BlockReaderRemote.java
@@ -480,7 +480,21 @@ void sendReadResult(Peer peer, Status statusCode) {
@Override
public int read(ByteBuffer buf) throws IOException {
- throw new UnsupportedOperationException("readDirect unsupported in
BlockReaderRemote");
+ int toRead = buf.remaining();
+ int nRead;
+ if (buf.isDirect()) {
+ byte[] bytes = new byte[toRead];
+ nRead = read(bytes, 0, toRead);
+ if (nRead > 0) {
+ buf.put(bytes, 0, nRead);
+ }
+ } else {
+ nRead = read(buf.array(), buf.arrayOffset(), toRead);
+ if (nRead > 0) {
+ buf.position(buf.position() + nRead);
+ }
+ }
+ return nRead;
}
{code}
> Use ByteBuffer in striping positional read
> ------------------------------------------
>
> Key: HDFS-8901
> URL: https://issues.apache.org/jira/browse/HDFS-8901
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Kai Zheng
> Assignee: Kai Zheng
> Attachments: HDFS-8901-v2.patch, HDFS-8901-v3.patch,
> HDFS-8901-v4.patch, HDFS-8901-v5.patch, HDFS-8901-v6.patch,
> HDFS-8901-v7.patch, HDFS-8901-v8.patch, HDFS-8901-v9.patch, initial-poc.patch
>
>
> Native erasure coder prefers to direct ByteBuffer for performance
> consideration. To prepare for it, this change uses ByteBuffer through the
> codes in implementing striping position read. It will also fix avoiding
> unnecessary data copying between striping read chunk buffers and decode input
> buffers.
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