/* This file is part of VoltDB.
* Copyright (C) 2008-2014 VoltDB Inc.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with VoltDB. If not, see <http://www.gnu.org/licenses/>.
*/
package org.voltcore.network;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.channels.GatheringByteChannel;
import java.util.ArrayDeque;
import java.util.concurrent.TimeUnit;
import org.voltcore.logging.Level;
import org.voltcore.logging.VoltLogger;
import org.voltcore.utils.DBBPool.BBContainer;
import org.voltcore.utils.DeferredSerialization;
import org.voltcore.utils.RateLimitedLogger;
/**
*
* Base class for tracking pending writes to a socket and dealing with serializing them
* to a series of buffers. Actually draining to a socket is delegated to subclasses as
* is queuing writes which have different locking and backpressure policies
*/
public abstract class NIOWriteStreamBase {
private static final VoltLogger networkLog = new VoltLogger("NETWORK");
protected boolean m_isShutdown = false;
protected BBContainer m_currentWriteBuffer = null;
/**
* Contains serialized buffers ready to write to the socket
*/
protected final ArrayDeque<BBContainer> m_queuedBuffers = new ArrayDeque<BBContainer>();
protected long m_bytesWritten = 0;
protected long m_messagesWritten = 0;
/*
* Used to provide incremental reads of the amount of
* data written.
* Stats now use a separate lock and risk reading dirty data
* rather than risk deadlock by acquiring the lock of the writestream.
*/
private long m_lastBytesWritten = 0;
private long m_lastMessagesWritten = 0;
long[] getBytesAndMessagesWritten(boolean interval) {
if (interval) {
final long bytesWrittenThisTime = m_bytesWritten - m_lastBytesWritten;
m_lastBytesWritten = m_bytesWritten;
final long messagesWrittenThisTime = m_messagesWritten - m_lastMessagesWritten;
m_lastMessagesWritten = m_messagesWritten;
return new long[] { bytesWrittenThisTime, messagesWrittenThisTime };
} else {
return new long[] {m_bytesWritten, m_messagesWritten};
}
}
/*
* Return the number of messages waiting to be written to the network
*/
public int getOutstandingMessageCount()
{
return m_queuedBuffers.size();
}
public boolean isEmpty()
{
return m_queuedBuffers.isEmpty() && m_currentWriteBuffer == null;
}
abstract int drainTo (final GatheringByteChannel channel) throws IOException;
protected abstract ArrayDeque<DeferredSerialization> getQueuedWrites();
/**
* Swap the two queues of DeferredSerializations and serialize everything into the queue
* of pending buffers
* @return
* @throws IOException
*/
final int swapAndSerializeQueuedWrites(final NetworkDBBPool pool) throws IOException {
int processedWrites = 0;
final ArrayDeque<DeferredSerialization> oldlist = getQueuedWrites();
if (oldlist.isEmpty()) return 0;
DeferredSerialization ds = null;
int bytesQueued = 0;
while ((ds = oldlist.poll()) != null) {
processedWrites++;
final int serializedSize = ds.getSerializedSize();
if (serializedSize == DeferredSerialization.EMPTY_MESSAGE_LENGTH) continue;
BBContainer outCont = m_queuedBuffers.peekLast();
ByteBuffer outbuf = null;
if (outCont == null || !outCont.b().hasRemaining()) {
outCont = pool.acquire();
outCont.b().clear();
m_queuedBuffers.offer(outCont);
}
outbuf = outCont.b();
//Fastpath, serialize to direct buffer creating no garbage
if (outbuf.remaining() >= serializedSize) {
final int oldLimit = outbuf.limit();
outbuf.limit(outbuf.position() + serializedSize);
final ByteBuffer slice = outbuf.slice();
ds.serialize(slice);
checkSloppySerialization(slice, ds);
slice.position(0);
bytesQueued += slice.remaining();
outbuf.position(outbuf.limit());
outbuf.limit(oldLimit);
} else {
//Slow path serialize to heap, and then put in buffers
ByteBuffer buf = ByteBuffer.allocate(serializedSize);
ds.serialize(buf);
checkSloppySerialization(buf, ds);
buf.position(0);
bytesQueued += buf.remaining();
while (buf.hasRemaining()) {
if (!outbuf.hasRemaining()) {
outCont = pool.acquire();
outbuf = outCont.b();
outbuf.clear();
m_queuedBuffers.offer(outCont);
}
if (outbuf.remaining() >= buf.remaining()) {
outbuf.put(buf);
} else {
final int oldLimit = buf.limit();
buf.limit(buf.position() + outbuf.remaining());
outbuf.put(buf);
buf.limit(oldLimit);
}
}
}
}
updateQueued(bytesQueued, true);
return processedWrites;
}
private static final boolean ASSERT_ON;
static {
boolean assertOn = false;
assert (assertOn = true);
ASSERT_ON = assertOn;
}
/*
* Validate that serialization is accurately reporting the amount of data necessary
* to serialize the message
*/
private void checkSloppySerialization(ByteBuffer buf, DeferredSerialization ds) {
if (buf.limit() != buf.capacity()) {
if (ASSERT_ON) {
networkLog.fatal("Sloppy serialization size for message class " + ds);
System.exit(-1);
}
RateLimitedLogger.tryLogForMessage(
System.currentTimeMillis(),
1, TimeUnit.HOURS,
networkLog,
Level.WARN, "Sloppy serialization size for message class %s", ds);
}
}
/**
* Free the pool resources that are held by this WriteStream. The pool itself is thread local
* and will be freed when the thread terminates.
*/
void shutdown() {
int bytesReleased = 0;
m_isShutdown = true;
BBContainer c = null;
if (m_currentWriteBuffer != null) {
bytesReleased += m_currentWriteBuffer.b().remaining();
m_currentWriteBuffer.discard();
}
while ((c = m_queuedBuffers.poll()) != null) {
//Buffer is not flipped after being written to in swap and serialize, need to do it here
c.b().flip();
bytesReleased += c.b().remaining();
c.discard();
}
updateQueued(-bytesReleased, false);
}
/*
* Track bytes queued for backpressure
*/
protected abstract void updateQueued(int queued, boolean noBackpressureSignal);
}