TestSeekBug.java
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上传日期:2018-01-08
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- /**
- * 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 junit.framework.TestCase;
- import java.io.*;
- import java.util.Random;
- import org.apache.hadoop.conf.Configuration;
- import org.apache.hadoop.fs.ChecksumFileSystem;
- import org.apache.hadoop.fs.FSDataInputStream;
- import org.apache.hadoop.fs.FSInputStream;
- import org.apache.hadoop.fs.FileSystem;
- import org.apache.hadoop.fs.Path;
- /**
- * This class tests the presence of seek bug as described
- * in HADOOP-508
- */
- public class TestSeekBug extends TestCase {
- static final long seed = 0xDEADBEEFL;
- static final int ONEMB = 1 << 20;
-
- private void writeFile(FileSystem fileSys, Path name) throws IOException {
- // create and write a file that contains 1MB
- DataOutputStream stm = fileSys.create(name);
- byte[] buffer = new byte[ONEMB];
- Random rand = new Random(seed);
- rand.nextBytes(buffer);
- stm.write(buffer);
- stm.close();
- }
-
- private void checkAndEraseData(byte[] actual, int from, byte[] expected, String message) {
- for (int idx = 0; idx < actual.length; idx++) {
- this.assertEquals(message+" byte "+(from+idx)+" differs. expected "+
- expected[from+idx]+" actual "+actual[idx],
- actual[idx], expected[from+idx]);
- actual[idx] = 0;
- }
- }
-
- private void seekReadFile(FileSystem fileSys, Path name) throws IOException {
- FSDataInputStream stm = fileSys.open(name, 4096);
- byte[] expected = new byte[ONEMB];
- Random rand = new Random(seed);
- rand.nextBytes(expected);
-
- // First read 128 bytes to set count in BufferedInputStream
- byte[] actual = new byte[128];
- stm.read(actual, 0, actual.length);
- // Now read a byte array that is bigger than the internal buffer
- actual = new byte[100000];
- stm.read(actual, 0, actual.length);
- checkAndEraseData(actual, 128, expected, "First Read Test");
- // now do a small seek, within the range that is already read
- stm.seek(96036); // 4 byte seek
- actual = new byte[128];
- stm.read(actual, 0, actual.length);
- checkAndEraseData(actual, 96036, expected, "Seek Bug");
- // all done
- stm.close();
- }
- /*
- * Read some data, skip a few bytes and read more. HADOOP-922.
- */
- private void smallReadSeek(FileSystem fileSys, Path name) throws IOException {
- if (fileSys instanceof ChecksumFileSystem) {
- fileSys = ((ChecksumFileSystem)fileSys).getRawFileSystem();
- }
- // Make the buffer size small to trigger code for HADOOP-922
- FSDataInputStream stmRaw = fileSys.open(name, 1);
- byte[] expected = new byte[ONEMB];
- Random rand = new Random(seed);
- rand.nextBytes(expected);
-
- // Issue a simple read first.
- byte[] actual = new byte[128];
- stmRaw.seek(100000);
- stmRaw.read(actual, 0, actual.length);
- checkAndEraseData(actual, 100000, expected, "First Small Read Test");
- // now do a small seek of 4 bytes, within the same block.
- int newpos1 = 100000 + 128 + 4;
- stmRaw.seek(newpos1);
- stmRaw.read(actual, 0, actual.length);
- checkAndEraseData(actual, newpos1, expected, "Small Seek Bug 1");
- // seek another 256 bytes this time
- int newpos2 = newpos1 + 256;
- stmRaw.seek(newpos2);
- stmRaw.read(actual, 0, actual.length);
- checkAndEraseData(actual, newpos2, expected, "Small Seek Bug 2");
- // all done
- stmRaw.close();
- }
-
- private void cleanupFile(FileSystem fileSys, Path name) throws IOException {
- assertTrue(fileSys.exists(name));
- fileSys.delete(name, true);
- assertTrue(!fileSys.exists(name));
- }
-
- /**
- * Test if the seek bug exists in FSDataInputStream in DFS.
- */
- public void testSeekBugDFS() throws IOException {
- Configuration conf = new Configuration();
- MiniDFSCluster cluster = new MiniDFSCluster(conf, 1, true, null);
- FileSystem fileSys = cluster.getFileSystem();
- try {
- Path file1 = new Path("seektest.dat");
- writeFile(fileSys, file1);
- seekReadFile(fileSys, file1);
- smallReadSeek(fileSys, file1);
- cleanupFile(fileSys, file1);
- } finally {
- fileSys.close();
- cluster.shutdown();
- }
- }
-
- /**
- * Tests if the seek bug exists in FSDataInputStream in LocalFS.
- */
- public void testSeekBugLocalFS() throws IOException {
- Configuration conf = new Configuration();
- FileSystem fileSys = FileSystem.getLocal(conf);
- try {
- Path file1 = new Path("build/test/data", "seektest.dat");
- writeFile(fileSys, file1);
- seekReadFile(fileSys, file1);
- cleanupFile(fileSys, file1);
- } finally {
- fileSys.close();
- }
- }
- }