Java PersistedRecoveryPaxosData类代码示例

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * In the case the node crashes in between downloading a log segment
 * and persisting the associated paxos recovery data, the log segment
 * will be left in its temporary location on disk. Given the paxos data,
 * we can check if this was indeed the case, and "roll forward"
 * the atomic operation.
 * 
 * See the inline comments in
 * {@link #acceptRecovery(RequestInfo, SegmentStateProto, URL)} for more
 * details.
 *
 * @throws IOException if the temporary file is unable to be renamed into
 * place
 */
private void completeHalfDoneAcceptRecovery(
    PersistedRecoveryPaxosData paxosData) throws IOException {
  if (paxosData == null) {
    return;
  }

  long segmentId = paxosData.getSegmentState().getStartTxId();
  long epoch = paxosData.getAcceptedInEpoch();
  
  File tmp = storage.getSyncLogTemporaryFile(segmentId, epoch);
  
  if (tmp.exists()) {
    File dst = storage.getInProgressEditLog(segmentId);
    LOG.info("Rolling forward previously half-completed synchronization: " +
        tmp + " -> " + dst);
    FileUtil.replaceFile(tmp, dst);
  }
}
 

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * Retrieve the persisted data for recovering the given segment from disk.
 */
private PersistedRecoveryPaxosData getPersistedPaxosData(long segmentTxId)
    throws IOException {
  File f = storage.getPaxosFile(segmentTxId);
  if (!f.exists()) {
    // Default instance has no fields filled in (they're optional)
    return null;
  }
  
  InputStream in = new FileInputStream(f);
  try {
    PersistedRecoveryPaxosData ret = PersistedRecoveryPaxosData.parseDelimitedFrom(in);
    Preconditions.checkState(ret != null &&
        ret.getSegmentState().getStartTxId() == segmentTxId,
        "Bad persisted data for segment %s: %s",
        segmentTxId, ret);
    return ret;
  } finally {
    IOUtils.closeStream(in);
  }
}
 

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * In the case the node crashes in between downloading a log segment
 * and persisting the associated paxos recovery data, the log segment
 * will be left in its temporary location on disk. Given the paxos data,
 * we can check if this was indeed the case, and "roll forward"
 * the atomic operation.
 * 
 * See the inline comments in
 * {@link #acceptRecovery(RequestInfo, SegmentStateProto, URL)} for more
 * details.
 *
 * @throws IOException if the temporary file is unable to be renamed into
 * place
 */
private void completeHalfDoneAcceptRecovery(
    PersistedRecoveryPaxosData paxosData) throws IOException {
  if (paxosData == null) {
    return;
  }

  long segmentId = paxosData.getSegmentState().getStartTxId();
  long epoch = paxosData.getAcceptedInEpoch();
  
  File tmp = journalStorage.getSyncLogTemporaryFile(segmentId, epoch);
  
  if (tmp.exists()) {
    File dst = journalStorage.getInProgressEditLog(segmentId);
    LOG.info("Rolling forward previously half-completed synchronization: " +
        tmp + " -> " + dst);
    FileUtil.replaceFile(tmp, dst);
  }
}
 

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * Retrieve the persisted data for recovering the given segment from disk.
 */
private PersistedRecoveryPaxosData getPersistedPaxosData(long segmentTxId)
    throws IOException {
  File f = journalStorage.getPaxosFile(segmentTxId);
  if (!f.exists()) {
    // Default instance has no fields filled in (they're optional)
    return null;
  }
  
  InputStream in = new FileInputStream(f);
  try {
    PersistedRecoveryPaxosData ret = PersistedRecoveryPaxosData.parseDelimitedFrom(in);
    Preconditions.checkState(ret != null &&
        ret.getSegmentState().getStartTxId() == segmentTxId,
        "Bad persisted data for segment %s: %s",
        segmentTxId, ret);
    return ret;
  } finally {
    IOUtils.closeStream(in);
  }
}
 

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * Persist data for recovering the given segment from disk.
 */
private void persistPaxosData(long segmentTxId,
    PersistedRecoveryPaxosData newData) throws IOException {
  File f = storage.getPaxosFile(segmentTxId);
  boolean success = false;
  AtomicFileOutputStream fos = new AtomicFileOutputStream(f);
  try {
    newData.writeDelimitedTo(fos);
    fos.write('\n');
    // Write human-readable data after the protobuf. This is only
    // to assist in debugging -- it's not parsed at all.
    OutputStreamWriter writer = new OutputStreamWriter(fos, Charsets.UTF_8);
    
    writer.write(String.valueOf(newData));
    writer.write('\n');
    writer.flush();
    
    fos.flush();
    success = true;
  } finally {
    if (success) {
      IOUtils.closeStream(fos);
    } else {
      fos.abort();
    }
  }
}
 

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * @see QJournalProtocol#prepareRecovery(RequestInfo, long)
 */
public synchronized PrepareRecoveryResponseProto prepareRecovery(
    RequestInfo reqInfo, long segmentTxId) throws IOException {
  checkJournalStorageFormatted();
  checkRequest(reqInfo);
  
  abortCurSegment();
  
  PrepareRecoveryResponseProto ret = new PrepareRecoveryResponseProto();

  PersistedRecoveryPaxosData previouslyAccepted = getPersistedPaxosData(segmentTxId);
  completeHalfDoneAcceptRecovery(previouslyAccepted);

  SegmentStateProto segInfo = getSegmentInfo(segmentTxId);
  boolean hasFinalizedSegment = segInfo != null && !segInfo.getIsInProgress();

  if (previouslyAccepted != null && !hasFinalizedSegment) {
    ret.setAcceptedInEpoch(previouslyAccepted.getAcceptedInEpoch());   
    ret.setSegmentState(previouslyAccepted.getSegmentState());
  } else {
    if (segInfo != null) {
      ret.setSegmentState(segInfo);
    }
  }
  
  ret.setLastWriterEpoch(lastWriterEpoch.get());
  if (committedTxnId.get() != HdfsConstants.INVALID_TXID) {
    ret.setLastCommittedTxId(committedTxnId.get());
  }
  
  LOG.info("Prepared recovery for segment " + segmentTxId + ": " + ret);
  return ret;
}
 

import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.PersistedRecoveryPaxosData; //导入依赖的package包/类
/**
 * Persist data for recovering the given segment from disk.
 */
private void persistPaxosData(long segmentTxId,
    PersistedRecoveryPaxosData newData) throws IOException {
  File f = journalStorage.getPaxosFile(segmentTxId);
  boolean success = false;
  AtomicFileOutputStream fos = new AtomicFileOutputStream(f);
  try {
    newData.writeDelimitedTo(fos);
    fos.write('\n');
    // Write human-readable data after the protobuf. This is only
    // to assist in debugging -- it's not parsed at all.
    OutputStreamWriter writer = new OutputStreamWriter(fos, Charsets.UTF_8);
    
    writer.write(String.valueOf(newData));
    writer.write('\n');
    writer.flush();
    
    fos.flush();
    success = true;
  } finally {
    if (success) {
      IOUtils.closeStream(fos);
    } else {
      fos.abort();
    }
  }
}