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Posted to common-commits@hadoop.apache.org by we...@apache.org on 2019/03/06 22:58:54 UTC
[hadoop] branch trunk updated: HDFS-14111. hdfsOpenFile on HDFS
causes unnecessary IO from file offset 0. Contributed by Sahil Takiar.
This is an automated email from the ASF dual-hosted git repository.
weichiu pushed a commit to branch trunk
in repository https://gitbox.apache.org/repos/asf/hadoop.git
The following commit(s) were added to refs/heads/trunk by this push:
new f5a4b43 HDFS-14111. hdfsOpenFile on HDFS causes unnecessary IO from file offset 0. Contributed by Sahil Takiar.
f5a4b43 is described below
commit f5a4b43a4944e1fcbdc86fc91c3a5179218cefdc
Author: Sahil Takiar <st...@apache.org>
AuthorDate: Wed Mar 6 14:57:46 2019 -0800
HDFS-14111. hdfsOpenFile on HDFS causes unnecessary IO from file offset 0. Contributed by Sahil Takiar.
Signed-off-by: Wei-Chiu Chuang <we...@apache.org>
---
.../apache/hadoop/crypto/CryptoInputStream.java | 1 +
.../hadoop/fs/ByteBufferPositionedReadable.java | 64 +++++
.../org/apache/hadoop/fs/StreamCapabilities.java | 6 +
.../org/apache/hadoop/hdfs/DFSInputStream.java | 1 +
.../src/main/native/libhdfs/hdfs.c | 29 ++-
.../main/native/libhdfspp/tests/hdfs_ext_test.cc | 5 +-
.../fsdataset/impl/AddBlockPoolException.java | 27 +++
.../apache/hadoop/hdfs/TestByteBufferPread.java | 269 +++++++++++++++++++++
8 files changed, 390 insertions(+), 12 deletions(-)
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java
index 5c879ec..67e8690 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/CryptoInputStream.java
@@ -740,6 +740,7 @@ public class CryptoInputStream extends FilterInputStream implements
case StreamCapabilities.READAHEAD:
case StreamCapabilities.DROPBEHIND:
case StreamCapabilities.UNBUFFER:
+ case StreamCapabilities.READBYTEBUFFER:
return true;
default:
return false;
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ByteBufferPositionedReadable.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ByteBufferPositionedReadable.java
new file mode 100644
index 0000000..873a521
--- /dev/null
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/ByteBufferPositionedReadable.java
@@ -0,0 +1,64 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.fs;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+/**
+ * Implementers of this interface provide a positioned read API that writes to a
+ * {@link ByteBuffer} rather than a {@code byte[]}.
+ *
+ * @see PositionedReadable
+ * @see ByteBufferReadable
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public interface ByteBufferPositionedReadable {
+ /**
+ * Reads up to {@code buf.remaining()} bytes into buf from a given position
+ * in the file and returns the number of bytes read. Callers should use
+ * {@code buf.limit(...)} to control the size of the desired read and
+ * {@code buf.position(...)} to control the offset into the buffer the data
+ * should be written to.
+ * <p>
+ * After a successful call, {@code buf.position()} will be advanced by the
+ * number of bytes read and {@code buf.limit()} should be unchanged.
+ * <p>
+ * In the case of an exception, the values of {@code buf.position()} and
+ * {@code buf.limit()} are undefined, and callers should be prepared to
+ * recover from this eventuality.
+ * <p>
+ * Many implementations will throw {@link UnsupportedOperationException}, so
+ * callers that are not confident in support for this method from the
+ * underlying filesystem should be prepared to handle that exception.
+ * <p>
+ * Implementations should treat 0-length requests as legitimate, and must not
+ * signal an error upon their receipt.
+ *
+ * @param position position within file
+ * @param buf the ByteBuffer to receive the results of the read operation.
+ * @return the number of bytes read, possibly zero, or -1 if reached
+ * end-of-stream
+ * @throws IOException if there is some error performing the read
+ */
+ int read(long position, ByteBuffer buf) throws IOException;
+}
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StreamCapabilities.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StreamCapabilities.java
index 3549cdc..c52d307 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StreamCapabilities.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/StreamCapabilities.java
@@ -60,6 +60,12 @@ public interface StreamCapabilities {
String UNBUFFER = "in:unbuffer";
/**
+ * Stream read(ByteBuffer) capability implemented by
+ * {@link ByteBufferReadable#read(java.nio.ByteBuffer)}.
+ */
+ String READBYTEBUFFER = "in:readbytebuffer";
+
+ /**
* Capabilities that a stream can support and be queried for.
*/
@Deprecated
diff --git a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
index f47b88c..a3e2ad5 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
+++ b/hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/DFSInputStream.java
@@ -1779,6 +1779,7 @@ public class DFSInputStream extends FSInputStream
case StreamCapabilities.READAHEAD:
case StreamCapabilities.DROPBEHIND:
case StreamCapabilities.UNBUFFER:
+ case StreamCapabilities.READBYTEBUFFER:
return true;
default:
return false;
diff --git a/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/hdfs.c b/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/hdfs.c
index 0cced97..41caffd 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/hdfs.c
+++ b/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfs/hdfs.c
@@ -1013,7 +1013,7 @@ static hdfsFile hdfsOpenFileImpl(hdfsFS fs, const char *path, int flags,
return f{is|os};
*/
int accmode = flags & O_ACCMODE;
- jstring jStrBufferSize = NULL, jStrReplication = NULL;
+ jstring jStrBufferSize = NULL, jStrReplication = NULL, jCapabilityString = NULL;
jobject jConfiguration = NULL, jPath = NULL, jFile = NULL;
jobject jFS = (jobject)fs;
jthrowable jthr;
@@ -1171,16 +1171,22 @@ static hdfsFile hdfsOpenFileImpl(hdfsFS fs, const char *path, int flags,
file->flags = 0;
if ((flags & O_WRONLY) == 0) {
- // Try a test read to see if we can do direct reads
- char buf;
- if (readDirect(fs, file, &buf, 0) == 0) {
- // Success - 0-byte read should return 0
+ // Check the StreamCapabilities of jFile to see if we can do direct reads
+ jthr = newJavaStr(env, "in:readbytebuffer", &jCapabilityString);
+ if (jthr) {
+ ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+ "hdfsOpenFile(%s): newJavaStr", path);
+ goto done;
+ }
+ jthr = invokeMethod(env, &jVal, INSTANCE, jFile, HADOOP_ISTRM,
+ "hasCapability", "(Ljava/lang/String;)Z", jCapabilityString);
+ if (jthr) {
+ ret = printExceptionAndFree(env, jthr, PRINT_EXC_ALL,
+ "hdfsOpenFile(%s): FSDataInputStream#hasCapability", path);
+ goto done;
+ }
+ if (jVal.z) {
file->flags |= HDFS_FILE_SUPPORTS_DIRECT_READ;
- } else if (errno != ENOTSUP) {
- // Unexpected error. Clear it, don't set the direct flag.
- fprintf(stderr,
- "hdfsOpenFile(%s): WARN: Unexpected error %d when testing "
- "for direct read compatibility\n", path, errno);
}
}
ret = 0;
@@ -1190,7 +1196,8 @@ done:
destroyLocalReference(env, jStrReplication);
destroyLocalReference(env, jConfiguration);
destroyLocalReference(env, jPath);
- destroyLocalReference(env, jFile);
+ destroyLocalReference(env, jFile);
+ destroyLocalReference(env, jCapabilityString);
if (ret) {
if (file) {
if (file->file) {
diff --git a/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc b/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc
index 19d95b4..79771f0 100644
--- a/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc
+++ b/hadoop-hdfs-project/hadoop-hdfs-native-client/src/main/native/libhdfspp/tests/hdfs_ext_test.cc
@@ -503,7 +503,10 @@ TEST_F(HdfsExtTest, TestReadStats) {
hdfsFileFreeReadStatistics(stats);
EXPECT_EQ(0, hdfsCloseFile(fs, file));
- EXPECT_EQ(0, errno);
+ // Since libhdfs is not guaranteed to set errno to 0 on successful
+ // operations, we disable this check for now, see HDFS-14325 for a
+ // long term solution to this problem
+ // EXPECT_EQ(0, errno);
}
//Testing working directory
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/AddBlockPoolException.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/AddBlockPoolException.java
new file mode 100644
index 0000000..1d2bca6
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/AddBlockPoolException.java
@@ -0,0 +1,27 @@
+package org.apache.hadoop.hdfs.server.datanode.fsdataset.impl;
+
+import java.io.IOException;
+import java.util.Map;
+import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
+
+/**
+ * This exception collects all IOExceptions thrown when adding block pools and
+ * scanning volumes. It keeps the information about which volume is associated
+ * with an exception.
+ *
+ */
+public class AddBlockPoolException extends IOException {
+ private Map<FsVolumeSpi, IOException> unhealthyDataDirs;
+ public AddBlockPoolException(Map<FsVolumeSpi, IOException>
+ unhealthyDataDirs) {
+ this.unhealthyDataDirs = unhealthyDataDirs;
+ }
+
+ public Map<FsVolumeSpi, IOException> getFailingVolumes() {
+ return unhealthyDataDirs;
+ }
+ @Override
+ public String toString() {
+ return getClass().getName() + ": " + unhealthyDataDirs.toString();
+ }
+}
\ No newline at end of file
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestByteBufferPread.java b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestByteBufferPread.java
new file mode 100644
index 0000000..64f2d06
--- /dev/null
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestByteBufferPread.java
@@ -0,0 +1,269 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+import java.util.Arrays;
+import java.util.Random;
+
+import static org.junit.Assert.assertArrayEquals;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+/**
+ * This class tests the DFS positional read functionality on a single node
+ * mini-cluster. These tests are inspired from {@link TestPread}. The tests
+ * are much less comprehensive than other pread tests because pread already
+ * internally uses {@link ByteBuffer}s.
+ */
+public class TestByteBufferPread {
+
+ private static MiniDFSCluster cluster;
+ private static FileSystem fs;
+ private static byte[] fileContents;
+ private static Path testFile;
+ private static Random rand;
+
+ private static final long SEED = 0xDEADBEEFL;
+ private static final int BLOCK_SIZE = 4096;
+ private static final int FILE_SIZE = 12 * BLOCK_SIZE;
+
+ @BeforeClass
+ public static void setup() throws IOException {
+ // Setup the cluster with a small block size so we can create small files
+ // that span multiple blocks
+ Configuration conf = new Configuration();
+ conf.setLong(DFSConfigKeys.DFS_BLOCK_SIZE_KEY, BLOCK_SIZE);
+ cluster = new MiniDFSCluster.Builder(conf).numDataNodes(3).build();
+ fs = cluster.getFileSystem();
+
+ // Create a test file that spans 12 blocks, and contains a bunch of random
+ // bytes
+ fileContents = new byte[FILE_SIZE];
+ rand = new Random(SEED);
+ rand.nextBytes(fileContents);
+ testFile = new Path("/byte-buffer-pread-test.dat");
+ try (FSDataOutputStream out = fs.create(testFile, (short) 3)) {
+ out.write(fileContents);
+ }
+ }
+
+ /**
+ * Test preads with {@link java.nio.HeapByteBuffer}s.
+ */
+ @Test
+ public void testPreadWithHeapByteBuffer() throws IOException {
+ testPreadWithByteBuffer(ByteBuffer.allocate(FILE_SIZE));
+ testPreadWithFullByteBuffer(ByteBuffer.allocate(FILE_SIZE));
+ testPreadWithPositionedByteBuffer(ByteBuffer.allocate(FILE_SIZE));
+ testPreadWithLimitedByteBuffer(ByteBuffer.allocate(FILE_SIZE));
+ testPositionedPreadWithByteBuffer(ByteBuffer.allocate(FILE_SIZE));
+ }
+
+ /**
+ * Test preads with {@link java.nio.DirectByteBuffer}s.
+ */
+ @Test
+ public void testPreadWithDirectByteBuffer() throws IOException {
+ testPreadWithByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
+ testPreadWithFullByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
+ testPreadWithPositionedByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
+ testPreadWithLimitedByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
+ testPositionedPreadWithByteBuffer(ByteBuffer.allocateDirect(FILE_SIZE));
+ }
+
+ /**
+ * Reads the entire testFile using the pread API and validates that its
+ * contents are properly loaded into the supplied {@link ByteBuffer}.
+ */
+ private void testPreadWithByteBuffer(ByteBuffer buffer) throws IOException {
+ int bytesRead;
+ int totalBytesRead = 0;
+ try (FSDataInputStream in = fs.open(testFile)) {
+ while ((bytesRead = in.read(totalBytesRead, buffer)) > 0) {
+ totalBytesRead += bytesRead;
+ // Check that each call to read changes the position of the ByteBuffer
+ // correctly
+ assertEquals(totalBytesRead, buffer.position());
+ }
+
+ // Make sure the buffer is full
+ assertFalse(buffer.hasRemaining());
+ // Make sure the contents of the read buffer equal the contents of the
+ // file
+ buffer.position(0);
+ byte[] bufferContents = new byte[FILE_SIZE];
+ buffer.get(bufferContents);
+ assertArrayEquals(bufferContents, fileContents);
+ buffer.position(buffer.limit());
+ }
+ }
+
+ /**
+ * Attempts to read the testFile into a {@link ByteBuffer} that is already
+ * full, and validates that doing so does not change the contents of the
+ * supplied {@link ByteBuffer}.
+ */
+ private void testPreadWithFullByteBuffer(ByteBuffer buffer)
+ throws IOException {
+ // Load some dummy data into the buffer
+ byte[] existingBufferBytes = new byte[FILE_SIZE];
+ rand.nextBytes(existingBufferBytes);
+ buffer.put(existingBufferBytes);
+ // Make sure the buffer is full
+ assertFalse(buffer.hasRemaining());
+
+ try (FSDataInputStream in = fs.open(testFile)) {
+ // Attempt to read into the buffer, 0 bytes should be read since the
+ // buffer is full
+ assertEquals(0, in.read(buffer));
+
+ // Double check the buffer is still full and its contents have not
+ // changed
+ assertFalse(buffer.hasRemaining());
+ buffer.position(0);
+ byte[] bufferContents = new byte[FILE_SIZE];
+ buffer.get(bufferContents);
+ assertArrayEquals(bufferContents, existingBufferBytes);
+ }
+ }
+
+ /**
+ * Reads half of the testFile into the {@link ByteBuffer} by setting a
+ * {@link ByteBuffer#limit} on the buffer. Validates that only half of the
+ * testFile is loaded into the buffer.
+ */
+ private void testPreadWithLimitedByteBuffer(
+ ByteBuffer buffer) throws IOException {
+ int bytesRead;
+ int totalBytesRead = 0;
+ // Set the buffer limit to half the size of the file
+ buffer.limit(FILE_SIZE / 2);
+
+ try (FSDataInputStream in = fs.open(testFile)) {
+ while ((bytesRead = in.read(totalBytesRead, buffer)) > 0) {
+ totalBytesRead += bytesRead;
+ // Check that each call to read changes the position of the ByteBuffer
+ // correctly
+ assertEquals(totalBytesRead, buffer.position());
+ }
+
+ // Since we set the buffer limit to half the size of the file, we should
+ // have only read half of the file into the buffer
+ assertEquals(totalBytesRead, FILE_SIZE / 2);
+ // Check that the buffer is full and the contents equal the first half of
+ // the file
+ assertFalse(buffer.hasRemaining());
+ buffer.position(0);
+ byte[] bufferContents = new byte[FILE_SIZE / 2];
+ buffer.get(bufferContents);
+ assertArrayEquals(bufferContents,
+ Arrays.copyOfRange(fileContents, 0, FILE_SIZE / 2));
+ }
+ }
+
+ /**
+ * Reads half of the testFile into the {@link ByteBuffer} by setting the
+ * {@link ByteBuffer#position} the half the size of the file. Validates that
+ * only half of the testFile is loaded into the buffer.
+ */
+ private void testPreadWithPositionedByteBuffer(
+ ByteBuffer buffer) throws IOException {
+ int bytesRead;
+ int totalBytesRead = 0;
+ // Set the buffer position to half the size of the file
+ buffer.position(FILE_SIZE / 2);
+
+ try (FSDataInputStream in = fs.open(testFile)) {
+ while ((bytesRead = in.read(totalBytesRead, buffer)) > 0) {
+ totalBytesRead += bytesRead;
+ // Check that each call to read changes the position of the ByteBuffer
+ // correctly
+ assertEquals(totalBytesRead + FILE_SIZE / 2, buffer.position());
+ }
+
+ // Since we set the buffer position to half the size of the file, we
+ // should have only read half of the file into the buffer
+ assertEquals(totalBytesRead, FILE_SIZE / 2);
+ // Check that the buffer is full and the contents equal the first half of
+ // the file
+ assertFalse(buffer.hasRemaining());
+ buffer.position(FILE_SIZE / 2);
+ byte[] bufferContents = new byte[FILE_SIZE / 2];
+ buffer.get(bufferContents);
+ assertArrayEquals(bufferContents,
+ Arrays.copyOfRange(fileContents, 0, FILE_SIZE / 2));
+ }
+ }
+
+ /**
+ * Reads half of the testFile into the {@link ByteBuffer} by specifying a
+ * position for the pread API that is half of the file size. Validates that
+ * only half of the testFile is loaded into the buffer.
+ */
+ private void testPositionedPreadWithByteBuffer(
+ ByteBuffer buffer) throws IOException {
+ int bytesRead;
+ int totalBytesRead = 0;
+
+ try (FSDataInputStream in = fs.open(testFile)) {
+ // Start reading from halfway through the file
+ while ((bytesRead = in.read(totalBytesRead + FILE_SIZE / 2,
+ buffer)) > 0) {
+ totalBytesRead += bytesRead;
+ // Check that each call to read changes the position of the ByteBuffer
+ // correctly
+ assertEquals(totalBytesRead, buffer.position());
+ }
+
+ // Since we starting reading halfway through the file, the buffer should
+ // only be half full
+ assertEquals(totalBytesRead, FILE_SIZE / 2);
+ assertEquals(buffer.position(), FILE_SIZE / 2);
+ assertTrue(buffer.hasRemaining());
+ // Check that the buffer contents equal the second half of the file
+ buffer.position(0);
+ byte[] bufferContents = new byte[FILE_SIZE / 2];
+ buffer.get(bufferContents);
+ assertArrayEquals(bufferContents,
+ Arrays.copyOfRange(fileContents, FILE_SIZE / 2, FILE_SIZE));
+ }
+ }
+
+ @AfterClass
+ public static void shutdown() throws IOException {
+ try {
+ fs.delete(testFile, false);
+ fs.close();
+ } finally {
+ cluster.shutdown(true);
+ }
+ }
+}
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