How to use

getTransactionId

method

in

org.apache.hadoop.hdfs.server.namenode.FSEditLogOp

 @Override
 public long scanOp() throws IOException {
  // Edit logs of this age don't have any length prefix, so we just have
  // to read the entire Op.
  FSEditLogOp op = decodeOp();
  return op == null ?
    HdfsServerConstants.INVALID_TXID : op.getTransactionId();
 }
}

 @Override
 public long scanOp() throws IOException {
  if (!NameNodeLayoutVersion.supports(
    LayoutVersion.Feature.STORED_TXIDS, logVersion)) {
   throw new IOException("Can't scan a pre-transactional edit log.");
  }
  FSEditLogOp op = decodeOp();
  return op == null ?
    HdfsServerConstants.INVALID_TXID : op.getTransactionId();
 }
}

/** 
 * Skip edit log operations up to a given transaction ID, or until the
 * end of the edit log is reached.
 *
 * After this function returns, the next call to readOp will return either
 * end-of-file (null) or a transaction with a txid equal to or higher than
 * the one we asked for.
 *
 * @param txid    The transaction ID to read up until.
 * @return        Returns true if we found a transaction ID greater than
 *                or equal to 'txid' in the log.
 */
public boolean skipUntil(long txid) throws IOException {
 while (true) {
  FSEditLogOp op = readOp();
  if (op == null) {
   return false;
  }
  if (op.getTransactionId() >= txid) {
   cachedOp = op;
   return true;
  }
 }
}

if (syncTxid > 0 && op.getTransactionId() > syncTxid) {
 breakOuter = true;
 break;
 totalEvents += eventBatch.getEvents().length;
if (op.getTransactionId() > maxSeenTxid) {
 maxSeenTxid = op.getTransactionId();
 firstSeenTxid = op.getTransactionId();
  op.getTransactionId() == syncTxid)) {

op = reader.readOp(skipBrokenEdits);
if ((op != null) && (op.hasTransactionId())) {
 long txId = op.getTransactionId();
 if ((txId >= lastTxId) &&
   (lastTxId != HdfsServerConstants.INVALID_TXID)) {

nextTxId = op.getTransactionId();
if (nextTxId <= 0) {
 nextTxId = 1;

 in.getPosition();
if (op.hasTransactionId()) {
 if (op.getTransactionId() > expectedTxId) { 
  MetaRecoveryContext.editLogLoaderPrompt("There appears " +
    "to be a gap in the edit log.  We expected txid " +
    expectedTxId + ", but got txid " +
    op.getTransactionId() + ".", recovery, "ignoring missing " +
    " transaction IDs");
 } else if (op.getTransactionId() < expectedTxId) { 
  MetaRecoveryContext.editLogLoaderPrompt("There appears " +
    "to be an out-of-order edit in the edit log.  We " +
    "expected txid " + expectedTxId + ", but got txid " +
    op.getTransactionId() + ".", recovery,
    "skipping the out-of-order edit");
  continue;
 lastAppliedTxId = op.getTransactionId();
 expectedTxId = lastAppliedTxId + 1;
} else {

if (fixTxIds) {
 if (nextTxId <= 0) {
  nextTxId = op.getTransactionId();
  if (nextTxId <= 0) {
   nextTxId = 1;

 prevTxId = op.getTransactionId();
 return op;
} catch (IOException e) {

/** 
 * Skip edit log operations up to a given transaction ID, or until the
 * end of the edit log is reached.
 *
 * After this function returns, the next call to readOp will return either
 * end-of-file (null) or a transaction with a txid equal to or higher than
 * the one we asked for.
 *
 * @param txid    The transaction ID to read up until.
 * @return        Returns true if we found a transaction ID greater than
 *                or equal to 'txid' in the log.
 */
public boolean skipUntil(long txid) throws IOException {
 while (true) {
  FSEditLogOp op = readOp();
  if (op == null) {
   return false;
  }
  if (op.getTransactionId() >= txid) {
   cachedOp = op;
   return true;
  }
 }
}

/** 
 * Skip edit log operations up to a given transaction ID, or until the
 * end of the edit log is reached.
 *
 * After this function returns, the next call to readOp will return either
 * end-of-file (null) or a transaction with a txid equal to or higher than
 * the one we asked for.
 *
 * @param txid    The transaction ID to read up until.
 * @return        Returns true if we found a transaction ID greater than
 *                or equal to 'txid' in the log.
 */
public boolean skipUntil(long txid) throws IOException {
 while (true) {
  FSEditLogOp op = readOp();
  if (op == null) {
   return false;
  }
  if (op.getTransactionId() >= txid) {
   cachedOp = op;
   return true;
  }
 }
}

static EditLogValidation scanEditLog(EditLogInputStream in) {
 long lastPos = 0;
 long lastTxId = HdfsConstants.INVALID_TXID;
 long numValid = 0;
 FSEditLogOp op = null;
 while (true) {
  lastPos = in.getPosition();
  try {
   if ((op = in.readOp()) == null) { // TODO
    break;
   }
  } catch (Throwable t) {
   FSImage.LOG.warn("Caught exception after reading " + numValid +
     " ops from " + in + " while determining its valid length." +
     "Position was " + lastPos, t);
   in.resync();
   FSImage.LOG.warn("After resync, position is " + in.getPosition());
   continue;
  }
  if (lastTxId == HdfsConstants.INVALID_TXID
    || op.getTransactionId() > lastTxId) {
   lastTxId = op.getTransactionId();
  }
  numValid++;
 }
 return new EditLogValidation(lastPos, lastTxId, false);
}

 || op.getTransactionId() > lastTxId) {
lastTxId = op.getTransactionId();

private static long readAllEdits(Collection<EditLogInputStream> streams,
  long startTxId) throws IOException {
 FSEditLogOp op;
 long nextTxId = startTxId;
 long numTx = 0;
 for (EditLogInputStream s : streams) {
  while (true) {
   op = s.readOp();
   if (op == null)
    break;
   if (op.getTransactionId() != nextTxId) {
    throw new IOException("out of order transaction ID!  expected " +
      nextTxId + " but got " + op.getTransactionId() + " when " +
      "reading " + s.getName());
   }
   numTx++;
   nextTxId = op.getTransactionId() + 1;
  }
 }
 return numTx;
}

} else {
 FSEditLogOp op = decodeOp();
 return op == null ? HdfsConstants.INVALID_TXID : op.getTransactionId();

static EditLogValidation scanEditLog(EditLogInputStream in) {
 long lastPos = 0;
 long lastTxId = HdfsConstants.INVALID_TXID;
 long numValid = 0;
 FSEditLogOp op = null;
 while (true) {
  lastPos = in.getPosition();
  try {
   if ((op = in.readOp()) == null) { // TODO
    break;
   }
  } catch (Throwable t) {
   FSImage.LOG.warn("Caught exception after reading " + numValid +
     " ops from " + in + " while determining its valid length." +
     "Position was " + lastPos, t);
   in.resync();
   FSImage.LOG.warn("After resync, position is " + in.getPosition());
   continue;
  }
  if (lastTxId == HdfsConstants.INVALID_TXID
    || op.getTransactionId() > lastTxId) {
   lastTxId = op.getTransactionId();
  }
  numValid++;
 }
 return new EditLogValidation(lastPos, lastTxId, false);
}

 || op.getTransactionId() > lastTxId) {
lastTxId = op.getTransactionId();

/**
 * Make sure that we starting reading the correct op when we request a stream
 * with a txid in the middle of an edit log file.
 */
@Test
public void testReadFromMiddleOfEditLog() throws CorruptionException,
  IOException {
 File f = new File(TestEditLog.TEST_DIR + "/readfrommiddleofeditlog");
 NNStorage storage = setupEdits(Collections.<URI>singletonList(f.toURI()), 
                 10);
 StorageDirectory sd = storage.dirIterator(NameNodeDirType.EDITS).next();
 
 FileJournalManager jm = new FileJournalManager(conf, sd, storage);
 
 EditLogInputStream elis = getJournalInputStream(jm, 5, true);
 try {
  FSEditLogOp op = elis.readOp();
  assertEquals("read unexpected op", op.getTransactionId(), 5);
 } finally {
  IOUtils.cleanup(LOG, elis);
 }
}

assertEquals(expected, op.getTransactionId());

/**
 * Make sure that in-progress streams aren't counted if we don't ask for
 * them.
 */
@Test
public void testExcludeInProgressStreams() throws CorruptionException,
  IOException {
 File f = new File(TestEditLog.TEST_DIR + "/excludeinprogressstreams");
 
 // Don't close the edit log once the files have been set up.
 NNStorage storage = setupEdits(Collections.<URI>singletonList(f.toURI()), 
                 10, false);
 StorageDirectory sd = storage.dirIterator(NameNodeDirType.EDITS).next();
 
 FileJournalManager jm = new FileJournalManager(conf, sd, storage);
 
 // If we exclude the in-progess stream, we should only have 100 tx.
 assertEquals(100, getNumberOfTransactions(jm, 1, false, false));
 
 EditLogInputStream elis = getJournalInputStream(jm, 90, false);
 try {
  FSEditLogOp lastReadOp = null;
  while ((lastReadOp = elis.readOp()) != null) {
   assertTrue(lastReadOp.getTransactionId() <= 100);
  }
 } finally {
  IOUtils.cleanup(LOG, elis);
 }
}