Java FSDataInputStream.releaseBuffer方法代碼示例

import org.apache.hadoop.fs.FSDataInputStream; //導入方法依賴的package包/類
/**
 * Test that when a client has a replica mmapped, we will not un-mlock that
 * replica for a reasonable amount of time, even if an uncache request
 * occurs.
 */
@Test(timeout=120000)
public void testPinning() throws Exception {
  assumeTrue(NativeCodeLoader.isNativeCodeLoaded() && !Path.WINDOWS);
  Configuration conf = getDefaultConf();
  // Set a really long revocation timeout, so that we won't reach it during
  // this test.
  conf.setLong(DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION_TIMEOUT_MS,
      1800000L);
  // Poll very often
  conf.setLong(DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION_POLLING_MS, 2L);
  MiniDFSCluster cluster = null;
  cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
  cluster.waitActive();
  DistributedFileSystem dfs = cluster.getFileSystem();

  // Create and cache a file.
  final String TEST_FILE = "/test_file";
  DFSTestUtil.createFile(dfs, new Path(TEST_FILE),
      BLOCK_SIZE, (short)1, 0xcafe);
  dfs.addCachePool(new CachePoolInfo("pool"));
  long cacheDirectiveId =
    dfs.addCacheDirective(new CacheDirectiveInfo.Builder().
      setPool("pool").setPath(new Path(TEST_FILE)).
        setReplication((short) 1).build());
  FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();
  DFSTestUtil.verifyExpectedCacheUsage(BLOCK_SIZE, 1, fsd);

  // Mmap the file.
  FSDataInputStream in = dfs.open(new Path(TEST_FILE));
  ByteBuffer buf =
      in.read(null, BLOCK_SIZE, EnumSet.noneOf(ReadOption.class));

  // Attempt to uncache file.  The file should still be cached.
  dfs.removeCacheDirective(cacheDirectiveId);
  Thread.sleep(500);
  DFSTestUtil.verifyExpectedCacheUsage(BLOCK_SIZE, 1, fsd);

  // Un-mmap the file.  The file should be uncached after this.
  in.releaseBuffer(buf);
  DFSTestUtil.verifyExpectedCacheUsage(0, 0, fsd);

  // Cleanup
  in.close();
  cluster.shutdown();
}
 

import org.apache.hadoop.fs.FSDataInputStream; //導入方法依賴的package包/類
/**
 * Test that when we have an uncache request, and the client refuses to release
 * the replica for a long time, we will un-mlock it.
 */
@Test(timeout=120000)
public void testRevocation() throws Exception {
  assumeTrue(NativeCodeLoader.isNativeCodeLoaded() && !Path.WINDOWS);
  BlockReaderTestUtil.enableHdfsCachingTracing();
  BlockReaderTestUtil.enableShortCircuitShmTracing();
  Configuration conf = getDefaultConf();
  // Set a really short revocation timeout.
  conf.setLong(DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION_TIMEOUT_MS, 250L);
  // Poll very often
  conf.setLong(DFSConfigKeys.DFS_DATANODE_CACHE_REVOCATION_POLLING_MS, 2L);
  MiniDFSCluster cluster = null;
  cluster = new MiniDFSCluster.Builder(conf).numDataNodes(1).build();
  cluster.waitActive();
  DistributedFileSystem dfs = cluster.getFileSystem();

  // Create and cache a file.
  final String TEST_FILE = "/test_file2";
  DFSTestUtil.createFile(dfs, new Path(TEST_FILE),
      BLOCK_SIZE, (short)1, 0xcafe);
  dfs.addCachePool(new CachePoolInfo("pool"));
  long cacheDirectiveId =
      dfs.addCacheDirective(new CacheDirectiveInfo.Builder().
          setPool("pool").setPath(new Path(TEST_FILE)).
          setReplication((short) 1).build());
  FsDatasetSpi<?> fsd = cluster.getDataNodes().get(0).getFSDataset();
  DFSTestUtil.verifyExpectedCacheUsage(BLOCK_SIZE, 1, fsd);

  // Mmap the file.
  FSDataInputStream in = dfs.open(new Path(TEST_FILE));
  ByteBuffer buf =
      in.read(null, BLOCK_SIZE, EnumSet.noneOf(ReadOption.class));

  // Attempt to uncache file.  The file should get uncached.
  LOG.info("removing cache directive {}", cacheDirectiveId);
  dfs.removeCacheDirective(cacheDirectiveId);
  LOG.info("finished removing cache directive {}", cacheDirectiveId);
  Thread.sleep(1000);
  DFSTestUtil.verifyExpectedCacheUsage(0, 0, fsd);

  // Cleanup
  in.releaseBuffer(buf);
  in.close();
  cluster.shutdown();
}