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HDFS-7308. Change the packet chunk size computation in DFSOutputStream in order to enforce packet size <= 64kB. Contributed by Takuya Fukudome

This commit is contained in:
Tsz-Wo Nicholas Sze 2015-02-27 23:45:37 +08:00
parent 4f75b15628
commit a979f3b58f
3 changed files with 36 additions and 1 deletions
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3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -682,6 +682,9 @@ Release 2.7.0 - UNRELEASED
HDFS-7819. Log WARN message for the blocks which are not in Block ID based
layout (Rakesh R via Colin P. McCabe)
HDFS-7308. Change the packet chunk size computation in DFSOutputStream in
order to enforce packet size <= 64kB. (Takuya Fukudome via szetszwo)
OPTIMIZATIONS
HDFS-7454. Reduce memory footprint for AclEntries in NameNode.

3
hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSOutputStream.java
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@ -1851,8 +1851,9 @@ public class DFSOutputStream extends FSOutputSummer
}
private void computePacketChunkSize(int psize, int csize) {
final int bodySize = psize - PacketHeader.PKT_MAX_HEADER_LEN;
final int chunkSize = csize + getChecksumSize();
chunksPerPacket = Math.max(psize/chunkSize, 1);
chunksPerPacket = Math.max(bodySize/chunkSize, 1);
packetSize = chunkSize*chunksPerPacket;
if (DFSClient.LOG.isDebugEnabled()) {
DFSClient.LOG.debug("computePacketChunkSize: src=" + src +

31
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSOutputStream.java
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@ -18,6 +18,8 @@
package org.apache.hadoop.hdfs;
import java.io.IOException;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.concurrent.atomic.AtomicReference;
import org.apache.hadoop.conf.Configuration;
@ -66,6 +68,35 @@ public class TestDFSOutputStream {
dos.close();
}
/**
* The computePacketChunkSize() method of DFSOutputStream should set the actual
* packet size < 64kB. See HDFS-7308 for details.
*/
@Test
public void testComputePacketChunkSize()
throws Exception {
DistributedFileSystem fs = cluster.getFileSystem();
FSDataOutputStream os = fs.create(new Path("/test"));
DFSOutputStream dos = (DFSOutputStream) Whitebox.getInternalState(os,
"wrappedStream");
final int packetSize = 64*1024;
final int bytesPerChecksum = 512;
Method method = dos.getClass().getDeclaredMethod("computePacketChunkSize",
int.class, int.class);
method.setAccessible(true);
method.invoke(dos, packetSize, bytesPerChecksum);
Field field = dos.getClass().getDeclaredField("packetSize");
field.setAccessible(true);
Assert.assertTrue((Integer) field.get(dos) + 33 < packetSize);
// If PKT_MAX_HEADER_LEN is 257, actual packet size come to over 64KB
// without a fix on HDFS-7308.
Assert.assertTrue((Integer) field.get(dos) + 257 < packetSize);
}
@AfterClass
public static void tearDown() {
cluster.shutdown();