Java LocatedBlock.getStartOffset方法代码示例

import org.apache.hadoop.hdfs.protocol.LocatedBlock; //导入方法依赖的package包/类
private LocatedBlocks makeBadBlockList(LocatedBlocks goodBlockList) {
  LocatedBlock goodLocatedBlock = goodBlockList.get(0);
  LocatedBlock badLocatedBlock = new LocatedBlock(
    goodLocatedBlock.getBlock(),
    new DatanodeInfo[] {
      DFSTestUtil.getDatanodeInfo("1.2.3.4", "bogus", 1234)
    },
    goodLocatedBlock.getStartOffset(),
    false);


  List<LocatedBlock> badBlocks = new ArrayList<LocatedBlock>();
  badBlocks.add(badLocatedBlock);
  return new LocatedBlocks(goodBlockList.getFileLength(), false,
                           badBlocks, null, true,
                           null);
}
 

import org.apache.hadoop.hdfs.protocol.LocatedBlock; //导入方法依赖的package包/类
private DNAddrPair chooseDataNode(LocatedBlock block,
    Collection<DatanodeInfo> ignoredNodes) throws IOException {
  while (true) {
    try {
      return getBestNodeDNAddrPair(block, ignoredNodes);
    } catch (IOException ie) {
      String errMsg = getBestNodeDNAddrPairErrorString(block.getLocations(),
        deadNodes, ignoredNodes);
      String blockInfo = block.getBlock() + " file=" + src;
      if (failures >= dfsClient.getMaxBlockAcquireFailures()) {
        String description = "Could not obtain block: " + blockInfo;
        DFSClient.LOG.warn(description + errMsg
            + ". Throwing a BlockMissingException");
        throw new BlockMissingException(src, description,
            block.getStartOffset());
      }

      DatanodeInfo[] nodes = block.getLocations();
      if (nodes == null || nodes.length == 0) {
        DFSClient.LOG.info("No node available for " + blockInfo);
      }
      DFSClient.LOG.info("Could not obtain " + block.getBlock()
          + " from any node: " + ie + errMsg
          + ". Will get new block locations from namenode and retry...");
      try {
        // Introducing a random factor to the wait time before another retry.
        // The wait time is dependent on # of failures and a random factor.
        // At the first time of getting a BlockMissingException, the wait time
        // is a random number between 0..3000 ms. If the first retry
        // still fails, we will wait 3000 ms grace period before the 2nd retry.
        // Also at the second retry, the waiting window is expanded to 6000 ms
        // alleviating the request rate from the server. Similarly the 3rd retry
        // will wait 6000ms grace period before retry and the waiting window is
        // expanded to 9000ms. 
        final int timeWindow = dfsClient.getConf().timeWindow;
        double waitTime = timeWindow * failures +       // grace period for the last round of attempt
          timeWindow * (failures + 1) * DFSUtil.getRandom().nextDouble(); // expanding time window for each failure
        DFSClient.LOG.warn("DFS chooseDataNode: got # " + (failures + 1) + " IOException, will wait for " + waitTime + " msec.");
        Thread.sleep((long)waitTime);
      } catch (InterruptedException iex) {
      }
      deadNodes.clear(); //2nd option is to remove only nodes[blockId]
      openInfo();
      block = getBlockAt(block.getStartOffset());
      failures++;
      continue;
    }
  }
}