How to use

isFlushed

method

in

org.apache.hadoop.hdfs.server.namenode.EditsDoubleBuffer

public void setReadyToFlush() {
 assert isFlushed() : "previous data not flushed yet";
 TxnBuffer tmp = bufReady;
 bufReady = bufCurrent;
 bufCurrent = tmp;
}

/**
 * There is no persistent storage. Just clear the buffers.
 */
@Override // EditLogOutputStream
public void create(int layoutVersion) throws IOException {
 assert doubleBuf.isFlushed() : "previous data is not flushed yet";
 this.doubleBuf = new EditsDoubleBuffer(DEFAULT_BUFFER_SIZE);
}

/**
 * Flush ready buffer to persistent store. currentBuffer is not flushed as it
 * accumulates new log records while readyBuffer will be flushed and synced.
 */
@Override
public void flushAndSync(boolean durable) throws IOException {
 if (fp == null) {
  throw new IOException("Trying to use aborted output stream");
 }
 if (doubleBuf.isFlushed()) {
  LOG.info("Nothing to flush");
  return;
 }
 preallocate(); // preallocate file if necessary
 doubleBuf.flushTo(fp);
 if (durable && !shouldSkipFsyncForTests && !shouldSyncWritesAndSkipFsync) {
  fc.force(false); // metadata updates not needed
 }
}

@Override // EditLogOutputStream
protected void flushAndSync(boolean durable) throws IOException {
 assert out.getLength() == 0 : "Output buffer is not empty";
 
 if (doubleBuf.isFlushed()) {
  LOG.info("Nothing to flush");
  return;
 }
 int numReadyTxns = doubleBuf.countReadyTxns();
 long firstTxToFlush = doubleBuf.getFirstReadyTxId();
 
 doubleBuf.flushTo(out);
 if (out.getLength() > 0) {
  assert numReadyTxns > 0;
  
  byte[] data = Arrays.copyOf(out.getData(), out.getLength());
  out.reset();
  assert out.getLength() == 0 : "Output buffer is not empty";
  backupNode.journal(journalInfo, 0, firstTxToFlush, numReadyTxns, data);
 }
}

void setReadyToFlush() {
 assert isFlushed() : "previous data not flushed yet";
 TxnBuffer tmp = bufReady;
 bufReady = bufCurrent;
 bufCurrent = tmp;
}

public void setReadyToFlush() {
 assert isFlushed() : "previous data not flushed yet";
 TxnBuffer tmp = bufReady;
 bufReady = bufCurrent;
 bufCurrent = tmp;
}

public void setReadyToFlush() {
 assert isFlushed() : "previous data not flushed yet";
 TxnBuffer tmp = bufReady;
 bufReady = bufCurrent;
 bufCurrent = tmp;
}

/**
 * There is no persistent storage. Just clear the buffers.
 */
@Override // EditLogOutputStream
public void create(int layoutVersion) throws IOException {
 assert doubleBuf.isFlushed() : "previous data is not flushed yet";
 this.doubleBuf = new EditsDoubleBuffer(DEFAULT_BUFFER_SIZE);
}

/**
 * There is no persistent storage. Just clear the buffers.
 */
@Override // EditLogOutputStream
public void create(int layoutVersion) throws IOException {
 assert doubleBuf.isFlushed() : "previous data is not flushed yet";
 this.doubleBuf = new EditsDoubleBuffer(DEFAULT_BUFFER_SIZE);
}

/**
 * Flush ready buffer to persistent store. currentBuffer is not flushed as it
 * accumulates new log records while readyBuffer will be flushed and synced.
 */
@Override
protected void flushAndSync() throws IOException {
 if (fp == null) {
  throw new IOException("Trying to use aborted output stream");
 }
 preallocate(); // preallocate file if necessary
 if (doubleBuf.isFlushed()) {
  return;
 }
 doubleBuf.flushTo(fp);
 fc.force(false); // metadata updates not needed
 fc.position(fc.position() - 1); // skip back the end-of-file marker         
}

/**
 * Flush ready buffer to persistent store. currentBuffer is not flushed as it
 * accumulates new log records while readyBuffer will be flushed and synced.
 */
@Override
public void flushAndSync(boolean durable) throws IOException {
 if (fp == null) {
  throw new IOException("Trying to use aborted output stream");
 }
 if (doubleBuf.isFlushed()) {
  LOG.info("Nothing to flush");
  return;
 }
 preallocate(); // preallocate file if necessary
 doubleBuf.flushTo(fp);
 if (durable && !shouldSkipFsyncForTests && !shouldSyncWritesAndSkipFsync) {
  fc.force(false); // metadata updates not needed
 }
}

/**
 * Flush ready buffer to persistent store. currentBuffer is not flushed as it
 * accumulates new log records while readyBuffer will be flushed and synced.
 */
@Override
public void flushAndSync(boolean durable) throws IOException {
 if (fp == null) {
  throw new IOException("Trying to use aborted output stream");
 }
 if (doubleBuf.isFlushed()) {
  LOG.info("Nothing to flush");
  return;
 }
 preallocate(); // preallocate file if necessary
 doubleBuf.flushTo(fp);
 if (durable && !shouldSkipFsyncForTests && !shouldSyncWritesAndSkipFsync) {
  fc.force(false); // metadata updates not needed
 }
}

@Override // EditLogOutputStream
protected void flushAndSync(boolean durable) throws IOException {
 assert out.getLength() == 0 : "Output buffer is not empty";
 
 if (doubleBuf.isFlushed()) {
  LOG.info("Nothing to flush");
  return;
 }
 int numReadyTxns = doubleBuf.countReadyTxns();
 long firstTxToFlush = doubleBuf.getFirstReadyTxId();
 
 doubleBuf.flushTo(out);
 if (out.getLength() > 0) {
  assert numReadyTxns > 0;
  
  byte[] data = Arrays.copyOf(out.getData(), out.getLength());
  out.reset();
  assert out.getLength() == 0 : "Output buffer is not empty";
  backupNode.journal(journalInfo, 0, firstTxToFlush, numReadyTxns, data);
 }
}

@Override // EditLogOutputStream
protected void flushAndSync(boolean durable) throws IOException {
 assert out.getLength() == 0 : "Output buffer is not empty";
 
 if (doubleBuf.isFlushed()) {
  LOG.info("Nothing to flush");
  return;
 }
 int numReadyTxns = doubleBuf.countReadyTxns();
 long firstTxToFlush = doubleBuf.getFirstReadyTxId();
 
 doubleBuf.flushTo(out);
 if (out.getLength() > 0) {
  assert numReadyTxns > 0;
  
  byte[] data = Arrays.copyOf(out.getData(), out.getLength());
  out.reset();
  assert out.getLength() == 0 : "Output buffer is not empty";
  backupNode.journal(journalInfo, 0, firstTxToFlush, numReadyTxns, data);
 }
}

EditsDoubleBuffer buf = new EditsDoubleBuffer(1024);
assertTrue(buf.isFlushed());
byte[] data = new byte[100];
buf.writeRaw(data, 0, data.length);
  buf.isFlushed());
assertEquals("Swapping buffers should still count buffered bytes",
  data.length, buf.countBufferedBytes());
assertFalse(buf.isFlushed());
buf.flushTo(outBuf);
assertEquals(data.length, outBuf.getLength());
assertTrue(buf.isFlushed());
assertEquals(0, buf.countBufferedBytes());