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simplify inputstream

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This commit is contained in:
Chris Lu 2020-07-16 10:54:29 -07:00
parent c9b50e8a22
commit 2629da2cb9
12 changed files with 58 additions and 1576 deletions
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137
other/java/hdfs2/src/main/java/seaweed/hdfs/ReadBuffer.java
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@ -1,137 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
import java.util.concurrent.CountDownLatch;
class ReadBuffer {
private SeaweedInputStream stream;
private long offset; // offset within the file for the buffer
private int length; // actual length, set after the buffer is filles
private int requestedLength; // requested length of the read
private byte[] buffer; // the buffer itself
private int bufferindex = -1; // index in the buffers array in Buffer manager
private ReadBufferStatus status; // status of the buffer
private CountDownLatch latch = null; // signaled when the buffer is done reading, so any client
// waiting on this buffer gets unblocked
// fields to help with eviction logic
private long timeStamp = 0; // tick at which buffer became available to read
private boolean isFirstByteConsumed = false;
private boolean isLastByteConsumed = false;
private boolean isAnyByteConsumed = false;
public SeaweedInputStream getStream() {
return stream;
}
public void setStream(SeaweedInputStream stream) {
this.stream = stream;
}
public long getOffset() {
return offset;
}
public void setOffset(long offset) {
this.offset = offset;
}
public int getLength() {
return length;
}
public void setLength(int length) {
this.length = length;
}
public int getRequestedLength() {
return requestedLength;
}
public void setRequestedLength(int requestedLength) {
this.requestedLength = requestedLength;
}
public byte[] getBuffer() {
return buffer;
}
public void setBuffer(byte[] buffer) {
this.buffer = buffer;
}
public int getBufferindex() {
return bufferindex;
}
public void setBufferindex(int bufferindex) {
this.bufferindex = bufferindex;
}
public ReadBufferStatus getStatus() {
return status;
}
public void setStatus(ReadBufferStatus status) {
this.status = status;
}
public CountDownLatch getLatch() {
return latch;
}
public void setLatch(CountDownLatch latch) {
this.latch = latch;
}
public long getTimeStamp() {
return timeStamp;
}
public void setTimeStamp(long timeStamp) {
this.timeStamp = timeStamp;
}
public boolean isFirstByteConsumed() {
return isFirstByteConsumed;
}
public void setFirstByteConsumed(boolean isFirstByteConsumed) {
this.isFirstByteConsumed = isFirstByteConsumed;
}
public boolean isLastByteConsumed() {
return isLastByteConsumed;
}
public void setLastByteConsumed(boolean isLastByteConsumed) {
this.isLastByteConsumed = isLastByteConsumed;
}
public boolean isAnyByteConsumed() {
return isAnyByteConsumed;
}
public void setAnyByteConsumed(boolean isAnyByteConsumed) {
this.isAnyByteConsumed = isAnyByteConsumed;
}
}

394
other/java/hdfs2/src/main/java/seaweed/hdfs/ReadBufferManager.java
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@ -1,394 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Collection;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;
import java.util.concurrent.CountDownLatch;
/**
* The Read Buffer Manager for Rest AbfsClient.
*/
final class ReadBufferManager {
private static final Logger LOGGER = LoggerFactory.getLogger(ReadBufferManager.class);
private static final int NUM_BUFFERS = 16;
private static final int BLOCK_SIZE = 4 * 1024 * 1024;
private static final int NUM_THREADS = 8;
private static final int THRESHOLD_AGE_MILLISECONDS = 3000; // have to see if 3 seconds is a good threshold
private Thread[] threads = new Thread[NUM_THREADS];
private byte[][] buffers; // array of byte[] buffers, to hold the data that is read
private Stack<Integer> freeList = new Stack<>(); // indices in buffers[] array that are available
private Queue<ReadBuffer> readAheadQueue = new LinkedList<>(); // queue of requests that are not picked up by any worker thread yet
private LinkedList<ReadBuffer> inProgressList = new LinkedList<>(); // requests being processed by worker threads
private LinkedList<ReadBuffer> completedReadList = new LinkedList<>(); // buffers available for reading
private static final ReadBufferManager BUFFER_MANAGER; // singleton, initialized in static initialization block
static {
BUFFER_MANAGER = new ReadBufferManager();
BUFFER_MANAGER.init();
}
static ReadBufferManager getBufferManager() {
return BUFFER_MANAGER;
}
private void init() {
buffers = new byte[NUM_BUFFERS][];
for (int i = 0; i < NUM_BUFFERS; i++) {
buffers[i] = new byte[BLOCK_SIZE]; // same buffers are reused. The byte array never goes back to GC
freeList.add(i);
}
for (int i = 0; i < NUM_THREADS; i++) {
Thread t = new Thread(new ReadBufferWorker(i));
t.setDaemon(true);
threads[i] = t;
t.setName("SeaweedFS-prefetch-" + i);
t.start();
}
ReadBufferWorker.UNLEASH_WORKERS.countDown();
}
// hide instance constructor
private ReadBufferManager() {
}
/*
*
* SeaweedInputStream-facing methods
*
*/
/**
* {@link SeaweedInputStream} calls this method to queue read-aheads.
*
* @param stream The {@link SeaweedInputStream} for which to do the read-ahead
* @param requestedOffset The offset in the file which shoukd be read
* @param requestedLength The length to read
*/
void queueReadAhead(final SeaweedInputStream stream, final long requestedOffset, final int requestedLength) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Start Queueing readAhead for {} offset {} length {}",
stream.getPath(), requestedOffset, requestedLength);
}
ReadBuffer buffer;
synchronized (this) {
if (isAlreadyQueued(stream, requestedOffset)) {
return; // already queued, do not queue again
}
if (freeList.isEmpty() && !tryEvict()) {
return; // no buffers available, cannot queue anything
}
buffer = new ReadBuffer();
buffer.setStream(stream);
buffer.setOffset(requestedOffset);
buffer.setLength(0);
buffer.setRequestedLength(requestedLength);
buffer.setStatus(ReadBufferStatus.NOT_AVAILABLE);
buffer.setLatch(new CountDownLatch(1));
Integer bufferIndex = freeList.pop(); // will return a value, since we have checked size > 0 already
buffer.setBuffer(buffers[bufferIndex]);
buffer.setBufferindex(bufferIndex);
readAheadQueue.add(buffer);
notifyAll();
}
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Done q-ing readAhead for file {} offset {} buffer idx {}",
stream.getPath(), requestedOffset, buffer.getBufferindex());
}
}
/**
* {@link SeaweedInputStream} calls this method read any bytes already available in a buffer (thereby saving a
* remote read). This returns the bytes if the data already exists in buffer. If there is a buffer that is reading
* the requested offset, then this method blocks until that read completes. If the data is queued in a read-ahead
* but not picked up by a worker thread yet, then it cancels that read-ahead and reports cache miss. This is because
* depending on worker thread availability, the read-ahead may take a while - the calling thread can do it's own
* read to get the data faster (copmared to the read waiting in queue for an indeterminate amount of time).
*
* @param stream the file to read bytes for
* @param position the offset in the file to do a read for
* @param length the length to read
* @param buffer the buffer to read data into. Note that the buffer will be written into from offset 0.
* @return the number of bytes read
*/
int getBlock(final SeaweedInputStream stream, final long position, final int length, final byte[] buffer) {
// not synchronized, so have to be careful with locking
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("getBlock for file {} position {} thread {}",
stream.getPath(), position, Thread.currentThread().getName());
}
waitForProcess(stream, position);
int bytesRead = 0;
synchronized (this) {
bytesRead = getBlockFromCompletedQueue(stream, position, length, buffer);
}
if (bytesRead > 0) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Done read from Cache for {} position {} length {}",
stream.getPath(), position, bytesRead);
}
return bytesRead;
}
// otherwise, just say we got nothing - calling thread can do its own read
return 0;
}
/*
*
* Internal methods
*
*/
private void waitForProcess(final SeaweedInputStream stream, final long position) {
ReadBuffer readBuf;
synchronized (this) {
clearFromReadAheadQueue(stream, position);
readBuf = getFromList(inProgressList, stream, position);
}
if (readBuf != null) { // if in in-progress queue, then block for it
try {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("got a relevant read buffer for file {} offset {} buffer idx {}",
stream.getPath(), readBuf.getOffset(), readBuf.getBufferindex());
}
readBuf.getLatch().await(); // blocking wait on the caller stream's thread
// Note on correctness: readBuf gets out of inProgressList only in 1 place: after worker thread
// is done processing it (in doneReading). There, the latch is set after removing the buffer from
// inProgressList. So this latch is safe to be outside the synchronized block.
// Putting it in synchronized would result in a deadlock, since this thread would be holding the lock
// while waiting, so no one will be able to change any state. If this becomes more complex in the future,
// then the latch cane be removed and replaced with wait/notify whenever inProgressList is touched.
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("latch done for file {} buffer idx {} length {}",
stream.getPath(), readBuf.getBufferindex(), readBuf.getLength());
}
}
}
/**
* If any buffer in the completedlist can be reclaimed then reclaim it and return the buffer to free list.
* The objective is to find just one buffer - there is no advantage to evicting more than one.
*
* @return whether the eviction succeeeded - i.e., were we able to free up one buffer
*/
private synchronized boolean tryEvict() {
ReadBuffer nodeToEvict = null;
if (completedReadList.size() <= 0) {
return false; // there are no evict-able buffers
}
// first, try buffers where all bytes have been consumed (approximated as first and last bytes consumed)
for (ReadBuffer buf : completedReadList) {
if (buf.isFirstByteConsumed() && buf.isLastByteConsumed()) {
nodeToEvict = buf;
break;
}
}
if (nodeToEvict != null) {
return evict(nodeToEvict);
}
// next, try buffers where any bytes have been consumed (may be a bad idea? have to experiment and see)
for (ReadBuffer buf : completedReadList) {
if (buf.isAnyByteConsumed()) {
nodeToEvict = buf;
break;
}
}
if (nodeToEvict != null) {
return evict(nodeToEvict);
}
// next, try any old nodes that have not been consumed
long earliestBirthday = Long.MAX_VALUE;
for (ReadBuffer buf : completedReadList) {
if (buf.getTimeStamp() < earliestBirthday) {
nodeToEvict = buf;
earliestBirthday = buf.getTimeStamp();
}
}
if ((currentTimeMillis() - earliestBirthday > THRESHOLD_AGE_MILLISECONDS) && (nodeToEvict != null)) {
return evict(nodeToEvict);
}
// nothing can be evicted
return false;
}
private boolean evict(final ReadBuffer buf) {
freeList.push(buf.getBufferindex());
completedReadList.remove(buf);
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Evicting buffer idx {}; was used for file {} offset {} length {}",
buf.getBufferindex(), buf.getStream().getPath(), buf.getOffset(), buf.getLength());
}
return true;
}
private boolean isAlreadyQueued(final SeaweedInputStream stream, final long requestedOffset) {
// returns true if any part of the buffer is already queued
return (isInList(readAheadQueue, stream, requestedOffset)
|| isInList(inProgressList, stream, requestedOffset)
|| isInList(completedReadList, stream, requestedOffset));
}
private boolean isInList(final Collection<ReadBuffer> list, final SeaweedInputStream stream, final long requestedOffset) {
return (getFromList(list, stream, requestedOffset) != null);
}
private ReadBuffer getFromList(final Collection<ReadBuffer> list, final SeaweedInputStream stream, final long requestedOffset) {
for (ReadBuffer buffer : list) {
if (buffer.getStream() == stream) {
if (buffer.getStatus() == ReadBufferStatus.AVAILABLE
&& requestedOffset >= buffer.getOffset()
&& requestedOffset < buffer.getOffset() + buffer.getLength()) {
return buffer;
} else if (requestedOffset >= buffer.getOffset()
&& requestedOffset < buffer.getOffset() + buffer.getRequestedLength()) {
return buffer;
}
}
}
return null;
}
private void clearFromReadAheadQueue(final SeaweedInputStream stream, final long requestedOffset) {
ReadBuffer buffer = getFromList(readAheadQueue, stream, requestedOffset);
if (buffer != null) {
readAheadQueue.remove(buffer);
notifyAll(); // lock is held in calling method
freeList.push(buffer.getBufferindex());
}
}
private int getBlockFromCompletedQueue(final SeaweedInputStream stream, final long position, final int length,
final byte[] buffer) {
ReadBuffer buf = getFromList(completedReadList, stream, position);
if (buf == null || position >= buf.getOffset() + buf.getLength()) {
return 0;
}
int cursor = (int) (position - buf.getOffset());
int availableLengthInBuffer = buf.getLength() - cursor;
int lengthToCopy = Math.min(length, availableLengthInBuffer);
System.arraycopy(buf.getBuffer(), cursor, buffer, 0, lengthToCopy);
if (cursor == 0) {
buf.setFirstByteConsumed(true);
}
if (cursor + lengthToCopy == buf.getLength()) {
buf.setLastByteConsumed(true);
}
buf.setAnyByteConsumed(true);
return lengthToCopy;
}
/*
*
* ReadBufferWorker-thread-facing methods
*
*/
/**
* ReadBufferWorker thread calls this to get the next buffer that it should work on.
*
* @return {@link ReadBuffer}
* @throws InterruptedException if thread is interrupted
*/
ReadBuffer getNextBlockToRead() throws InterruptedException {
ReadBuffer buffer = null;
synchronized (this) {
//buffer = readAheadQueue.take(); // blocking method
while (readAheadQueue.size() == 0) {
wait();
}
buffer = readAheadQueue.remove();
notifyAll();
if (buffer == null) {
return null; // should never happen
}
buffer.setStatus(ReadBufferStatus.READING_IN_PROGRESS);
inProgressList.add(buffer);
}
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("ReadBufferWorker picked file {} for offset {}",
buffer.getStream().getPath(), buffer.getOffset());
}
return buffer;
}
/**
* ReadBufferWorker thread calls this method to post completion.
*
* @param buffer the buffer whose read was completed
* @param result the {@link ReadBufferStatus} after the read operation in the worker thread
* @param bytesActuallyRead the number of bytes that the worker thread was actually able to read
*/
void doneReading(final ReadBuffer buffer, final ReadBufferStatus result, final int bytesActuallyRead) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("ReadBufferWorker completed file {} for offset {} bytes {}",
buffer.getStream().getPath(), buffer.getOffset(), bytesActuallyRead);
}
synchronized (this) {
inProgressList.remove(buffer);
if (result == ReadBufferStatus.AVAILABLE && bytesActuallyRead > 0) {
buffer.setStatus(ReadBufferStatus.AVAILABLE);
buffer.setTimeStamp(currentTimeMillis());
buffer.setLength(bytesActuallyRead);
completedReadList.add(buffer);
} else {
freeList.push(buffer.getBufferindex());
// buffer should go out of scope after the end of the calling method in ReadBufferWorker, and eligible for GC
}
}
//outside the synchronized, since anyone receiving a wake-up from the latch must see safe-published results
buffer.getLatch().countDown(); // wake up waiting threads (if any)
}
/**
* Similar to System.currentTimeMillis, except implemented with System.nanoTime().
* System.currentTimeMillis can go backwards when system clock is changed (e.g., with NTP time synchronization),
* making it unsuitable for measuring time intervals. nanotime is strictly monotonically increasing per CPU core.
* Note: it is not monotonic across Sockets, and even within a CPU, its only the
* more recent parts which share a clock across all cores.
*
* @return current time in milliseconds
*/
private long currentTimeMillis() {
return System.nanoTime() / 1000 / 1000;
}
}

29
other/java/hdfs2/src/main/java/seaweed/hdfs/ReadBufferStatus.java
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@ -1,29 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
/**
* The ReadBufferStatus for Rest AbfsClient
*/
public enum ReadBufferStatus {
NOT_AVAILABLE, // buffers sitting in readaheadqueue have this stats
READING_IN_PROGRESS, // reading is in progress on this buffer. Buffer should be in inProgressList
AVAILABLE, // data is available in buffer. It should be in completedList
READ_FAILED // read completed, but failed.
}

70
other/java/hdfs2/src/main/java/seaweed/hdfs/ReadBufferWorker.java
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@ -1,70 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
import java.util.concurrent.CountDownLatch;
class ReadBufferWorker implements Runnable {
protected static final CountDownLatch UNLEASH_WORKERS = new CountDownLatch(1);
private int id;
ReadBufferWorker(final int id) {
this.id = id;
}
/**
* return the ID of ReadBufferWorker.
*/
public int getId() {
return this.id;
}
/**
* Waits until a buffer becomes available in ReadAheadQueue.
* Once a buffer becomes available, reads the file specified in it and then posts results back to buffer manager.
* Rinse and repeat. Forever.
*/
public void run() {
try {
UNLEASH_WORKERS.await();
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
ReadBufferManager bufferManager = ReadBufferManager.getBufferManager();
ReadBuffer buffer;
while (true) {
try {
buffer = bufferManager.getNextBlockToRead(); // blocks, until a buffer is available for this thread
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
return;
}
if (buffer != null) {
try {
// do the actual read, from the file.
int bytesRead = buffer.getStream().readRemote(buffer.getOffset(), buffer.getBuffer(), 0, buffer.getRequestedLength());
bufferManager.doneReading(buffer, ReadBufferStatus.AVAILABLE, bytesRead); // post result back to ReadBufferManager
} catch (Exception ex) {
bufferManager.doneReading(buffer, ReadBufferStatus.READ_FAILED, 0);
}
}
}
}
}

4
other/java/hdfs2/src/main/java/seaweed/hdfs/SeaweedFileSystemStore.java
View File

@ -212,7 +212,6 @@ public class SeaweedFileSystemStore {
LOG.debug("openFileForRead path:{} bufferSize:{}", path, bufferSize);
int readAheadQueueDepth = 2;
FilerProto.Entry entry = lookupEntry(path);
if (entry == null) {
@ -223,8 +222,7 @@ public class SeaweedFileSystemStore {
statistics,
path.toUri().getPath(),
entry,
bufferSize,
readAheadQueueDepth);
bufferSize);
}
public void setOwner(Path path, String owner, String group) {

169
other/java/hdfs2/src/main/java/seaweed/hdfs/SeaweedInputStream.java
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@ -27,16 +27,9 @@ public class SeaweedInputStream extends FSInputStream {
private final List<SeaweedRead.VisibleInterval> visibleIntervalList;
private final long contentLength;
private final int bufferSize; // default buffer size
private final int readAheadQueueDepth; // initialized in constructor
private final boolean readAheadEnabled; // whether enable readAhead;
private byte[] buffer = null; // will be initialized on first use
private long position = 0; // cursor of the file
private long fCursor = 0; // cursor of buffer within file - offset of next byte to read from remote server
private long fCursorAfterLastRead = -1;
private int bCursor = 0; // cursor of read within buffer - offset of next byte to be returned from buffer
private int limit = 0; // offset of next byte to be read into buffer from service (i.e., upper marker+1
// of valid bytes in buffer)
private boolean closed = false;
public SeaweedInputStream(
@ -44,16 +37,13 @@ public class SeaweedInputStream extends FSInputStream {
final Statistics statistics,
final String path,
final FilerProto.Entry entry,
final int bufferSize,
final int readAheadQueueDepth) {
final int bufferSize) {
this.filerGrpcClient = filerGrpcClient;
this.statistics = statistics;
this.path = path;
this.entry = entry;
this.contentLength = SeaweedRead.totalSize(entry.getChunksList());
this.bufferSize = bufferSize;
this.readAheadQueueDepth = (readAheadQueueDepth >= 0) ? readAheadQueueDepth : Runtime.getRuntime().availableProcessors();
this.readAheadEnabled = true;
this.visibleIntervalList = SeaweedRead.nonOverlappingVisibleIntervals(entry.getChunksList());
@ -78,122 +68,7 @@ public class SeaweedInputStream extends FSInputStream {
@Override
public synchronized int read(final byte[] b, final int off, final int len) throws IOException {
int currentOff = off;
int currentLen = len;
int lastReadBytes;
int totalReadBytes = 0;
do {
lastReadBytes = readOneBlock(b, currentOff, currentLen);
if (lastReadBytes > 0) {
currentOff += lastReadBytes;
currentLen -= lastReadBytes;
totalReadBytes += lastReadBytes;
}
if (currentLen <= 0 || currentLen > b.length - currentOff) {
break;
}
} while (lastReadBytes > 0);
return totalReadBytes > 0 ? totalReadBytes : lastReadBytes;
}
private int readOneBlock(final byte[] b, final int off, final int len) throws IOException {
if (closed) {
throw new IOException(FSExceptionMessages.STREAM_IS_CLOSED);
}
Preconditions.checkNotNull(b);
if (len == 0) {
return 0;
}
if (this.available() == 0) {
return -1;
}
if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
}
//If buffer is empty, then fill the buffer.
if (bCursor == limit) {
//If EOF, then return -1
if (fCursor >= contentLength) {
return -1;
}
long bytesRead = 0;
//reset buffer to initial state - i.e., throw away existing data
bCursor = 0;
limit = 0;
if (buffer == null) {
buffer = new byte[bufferSize];
}
// Enable readAhead when reading sequentially
if (-1 == fCursorAfterLastRead || fCursorAfterLastRead == fCursor || b.length >= bufferSize) {
bytesRead = readInternal(fCursor, buffer, 0, bufferSize, false);
} else {
bytesRead = readInternal(fCursor, buffer, 0, b.length, true);
}
if (bytesRead == -1) {
return -1;
}
limit += bytesRead;
fCursor += bytesRead;
fCursorAfterLastRead = fCursor;
}
//If there is anything in the buffer, then return lesser of (requested bytes) and (bytes in buffer)
//(bytes returned may be less than requested)
int bytesRemaining = limit - bCursor;
int bytesToRead = Math.min(len, bytesRemaining);
System.arraycopy(buffer, bCursor, b, off, bytesToRead);
bCursor += bytesToRead;
if (statistics != null) {
statistics.incrementBytesRead(bytesToRead);
}
return bytesToRead;
}
private int readInternal(final long position, final byte[] b, final int offset, final int length,
final boolean bypassReadAhead) throws IOException {
if (readAheadEnabled && !bypassReadAhead) {
// try reading from read-ahead
if (offset != 0) {
throw new IllegalArgumentException("readahead buffers cannot have non-zero buffer offsets");
}
int receivedBytes;
// queue read-aheads
int numReadAheads = this.readAheadQueueDepth;
long nextSize;
long nextOffset = position;
while (numReadAheads > 0 && nextOffset < contentLength) {
nextSize = Math.min((long) bufferSize, contentLength - nextOffset);
ReadBufferManager.getBufferManager().queueReadAhead(this, nextOffset, (int) nextSize);
nextOffset = nextOffset + nextSize;
numReadAheads--;
}
// try reading from buffers first
receivedBytes = ReadBufferManager.getBufferManager().getBlock(this, position, length, b);
if (receivedBytes > 0) {
return receivedBytes;
}
// got nothing from read-ahead, do our own read now
receivedBytes = readRemote(position, b, offset, length);
return receivedBytes;
} else {
return readRemote(position, b, offset, length);
}
}
int readRemote(long position, byte[] b, int offset, int length) throws IOException {
if (position < 0) {
throw new IllegalArgumentException("attempting to read from negative offset");
}
@ -203,21 +78,30 @@ public class SeaweedInputStream extends FSInputStream {
if (b == null) {
throw new IllegalArgumentException("null byte array passed in to read() method");
}
if (offset >= b.length) {
if (off >= b.length) {
throw new IllegalArgumentException("offset greater than length of array");
}
if (length < 0) {
if (len < 0) {
throw new IllegalArgumentException("requested read length is less than zero");
}
if (length > (b.length - offset)) {
if (len > (b.length - off)) {
throw new IllegalArgumentException("requested read length is more than will fit after requested offset in buffer");
}
long bytesRead = SeaweedRead.read(filerGrpcClient, visibleIntervalList, position, b, offset, length);
long bytesRead = SeaweedRead.read(this.filerGrpcClient, this.visibleIntervalList, this.position, b, off, len);
if (bytesRead > Integer.MAX_VALUE) {
throw new IOException("Unexpected Content-Length");
}
if (bytesRead > 0) {
this.position += bytesRead;
if (statistics != null) {
statistics.incrementBytesRead(bytesRead);
}
}
return (int)bytesRead;
}
/**
@ -239,17 +123,8 @@ public class SeaweedInputStream extends FSInputStream {
throw new EOFException(FSExceptionMessages.CANNOT_SEEK_PAST_EOF);
}
if (n >= fCursor - limit && n <= fCursor) { // within buffer
bCursor = (int) (n - (fCursor - limit));
return;
}
this.position = n;
// next read will read from here
fCursor = n;
//invalidate buffer
limit = 0;
bCursor = 0;
}
@Override
@ -257,20 +132,19 @@ public class SeaweedInputStream extends FSInputStream {
if (closed) {
throw new IOException(FSExceptionMessages.STREAM_IS_CLOSED);
}
long currentPos = getPos();
if (currentPos == contentLength) {
if (this.position == contentLength) {
if (n > 0) {
throw new EOFException(FSExceptionMessages.CANNOT_SEEK_PAST_EOF);
}
}
long newPos = currentPos + n;
long newPos = this.position + n;
if (newPos < 0) {
newPos = 0;
n = newPos - currentPos;
n = newPos - this.position;
}
if (newPos > contentLength) {
newPos = contentLength;
n = newPos - currentPos;
n = newPos - this.position;
}
seek(newPos);
return n;
@ -321,7 +195,7 @@ public class SeaweedInputStream extends FSInputStream {
if (closed) {
throw new IOException(FSExceptionMessages.STREAM_IS_CLOSED);
}
return fCursor - limit + bCursor;
return position;
}
/**
@ -338,7 +212,6 @@ public class SeaweedInputStream extends FSInputStream {
@Override
public synchronized void close() throws IOException {
closed = true;
buffer = null; // de-reference the buffer so it can be GC'ed sooner
}
/**

137
other/java/hdfs3/src/main/java/seaweed/hdfs/ReadBuffer.java
View File

@ -1,137 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
import java.util.concurrent.CountDownLatch;
class ReadBuffer {
private SeaweedInputStream stream;
private long offset; // offset within the file for the buffer
private int length; // actual length, set after the buffer is filles
private int requestedLength; // requested length of the read
private byte[] buffer; // the buffer itself
private int bufferindex = -1; // index in the buffers array in Buffer manager
private ReadBufferStatus status; // status of the buffer
private CountDownLatch latch = null; // signaled when the buffer is done reading, so any client
// waiting on this buffer gets unblocked
// fields to help with eviction logic
private long timeStamp = 0; // tick at which buffer became available to read
private boolean isFirstByteConsumed = false;
private boolean isLastByteConsumed = false;
private boolean isAnyByteConsumed = false;
public SeaweedInputStream getStream() {
return stream;
}
public void setStream(SeaweedInputStream stream) {
this.stream = stream;
}
public long getOffset() {
return offset;
}
public void setOffset(long offset) {
this.offset = offset;
}
public int getLength() {
return length;
}
public void setLength(int length) {
this.length = length;
}
public int getRequestedLength() {
return requestedLength;
}
public void setRequestedLength(int requestedLength) {
this.requestedLength = requestedLength;
}
public byte[] getBuffer() {
return buffer;
}
public void setBuffer(byte[] buffer) {
this.buffer = buffer;
}
public int getBufferindex() {
return bufferindex;
}
public void setBufferindex(int bufferindex) {
this.bufferindex = bufferindex;
}
public ReadBufferStatus getStatus() {
return status;
}
public void setStatus(ReadBufferStatus status) {
this.status = status;
}
public CountDownLatch getLatch() {
return latch;
}
public void setLatch(CountDownLatch latch) {
this.latch = latch;
}
public long getTimeStamp() {
return timeStamp;
}
public void setTimeStamp(long timeStamp) {
this.timeStamp = timeStamp;
}
public boolean isFirstByteConsumed() {
return isFirstByteConsumed;
}
public void setFirstByteConsumed(boolean isFirstByteConsumed) {
this.isFirstByteConsumed = isFirstByteConsumed;
}
public boolean isLastByteConsumed() {
return isLastByteConsumed;
}
public void setLastByteConsumed(boolean isLastByteConsumed) {
this.isLastByteConsumed = isLastByteConsumed;
}
public boolean isAnyByteConsumed() {
return isAnyByteConsumed;
}
public void setAnyByteConsumed(boolean isAnyByteConsumed) {
this.isAnyByteConsumed = isAnyByteConsumed;
}
}

394
other/java/hdfs3/src/main/java/seaweed/hdfs/ReadBufferManager.java
View File

@ -1,394 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
* <p>
* http://www.apache.org/licenses/LICENSE-2.0
* <p>
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.Collection;
import java.util.LinkedList;
import java.util.Queue;
import java.util.Stack;
import java.util.concurrent.CountDownLatch;
/**
* The Read Buffer Manager for Rest AbfsClient.
*/
final class ReadBufferManager {
private static final Logger LOGGER = LoggerFactory.getLogger(ReadBufferManager.class);
private static final int NUM_BUFFERS = 16;
private static final int BLOCK_SIZE = 4 * 1024 * 1024;
private static final int NUM_THREADS = 8;
private static final int THRESHOLD_AGE_MILLISECONDS = 3000; // have to see if 3 seconds is a good threshold
private Thread[] threads = new Thread[NUM_THREADS];
private byte[][] buffers; // array of byte[] buffers, to hold the data that is read
private Stack<Integer> freeList = new Stack<>(); // indices in buffers[] array that are available
private Queue<ReadBuffer> readAheadQueue = new LinkedList<>(); // queue of requests that are not picked up by any worker thread yet
private LinkedList<ReadBuffer> inProgressList = new LinkedList<>(); // requests being processed by worker threads
private LinkedList<ReadBuffer> completedReadList = new LinkedList<>(); // buffers available for reading
private static final ReadBufferManager BUFFER_MANAGER; // singleton, initialized in static initialization block
static {
BUFFER_MANAGER = new ReadBufferManager();
BUFFER_MANAGER.init();
}
static ReadBufferManager getBufferManager() {
return BUFFER_MANAGER;
}
private void init() {
buffers = new byte[NUM_BUFFERS][];
for (int i = 0; i < NUM_BUFFERS; i++) {
buffers[i] = new byte[BLOCK_SIZE]; // same buffers are reused. The byte array never goes back to GC
freeList.add(i);
}
for (int i = 0; i < NUM_THREADS; i++) {
Thread t = new Thread(new ReadBufferWorker(i));
t.setDaemon(true);
threads[i] = t;
t.setName("SeaweedFS-prefetch-" + i);
t.start();
}
ReadBufferWorker.UNLEASH_WORKERS.countDown();
}
// hide instance constructor
private ReadBufferManager() {
}
/*
*
* SeaweedInputStream-facing methods
*
*/
/**
* {@link SeaweedInputStream} calls this method to queue read-aheads.
*
* @param stream The {@link SeaweedInputStream} for which to do the read-ahead
* @param requestedOffset The offset in the file which shoukd be read
* @param requestedLength The length to read
*/
void queueReadAhead(final SeaweedInputStream stream, final long requestedOffset, final int requestedLength) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Start Queueing readAhead for {} offset {} length {}",
stream.getPath(), requestedOffset, requestedLength);
}
ReadBuffer buffer;
synchronized (this) {
if (isAlreadyQueued(stream, requestedOffset)) {
return; // already queued, do not queue again
}
if (freeList.isEmpty() && !tryEvict()) {
return; // no buffers available, cannot queue anything
}
buffer = new ReadBuffer();
buffer.setStream(stream);
buffer.setOffset(requestedOffset);
buffer.setLength(0);
buffer.setRequestedLength(requestedLength);
buffer.setStatus(ReadBufferStatus.NOT_AVAILABLE);
buffer.setLatch(new CountDownLatch(1));
Integer bufferIndex = freeList.pop(); // will return a value, since we have checked size > 0 already
buffer.setBuffer(buffers[bufferIndex]);
buffer.setBufferindex(bufferIndex);
readAheadQueue.add(buffer);
notifyAll();
}
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Done q-ing readAhead for file {} offset {} buffer idx {}",
stream.getPath(), requestedOffset, buffer.getBufferindex());
}
}
/**
* {@link SeaweedInputStream} calls this method read any bytes already available in a buffer (thereby saving a
* remote read). This returns the bytes if the data already exists in buffer. If there is a buffer that is reading
* the requested offset, then this method blocks until that read completes. If the data is queued in a read-ahead
* but not picked up by a worker thread yet, then it cancels that read-ahead and reports cache miss. This is because
* depending on worker thread availability, the read-ahead may take a while - the calling thread can do it's own
* read to get the data faster (copmared to the read waiting in queue for an indeterminate amount of time).
*
* @param stream the file to read bytes for
* @param position the offset in the file to do a read for
* @param length the length to read
* @param buffer the buffer to read data into. Note that the buffer will be written into from offset 0.
* @return the number of bytes read
*/
int getBlock(final SeaweedInputStream stream, final long position, final int length, final byte[] buffer) {
// not synchronized, so have to be careful with locking
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("getBlock for file {} position {} thread {}",
stream.getPath(), position, Thread.currentThread().getName());
}
waitForProcess(stream, position);
int bytesRead = 0;
synchronized (this) {
bytesRead = getBlockFromCompletedQueue(stream, position, length, buffer);
}
if (bytesRead > 0) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Done read from Cache for {} position {} length {}",
stream.getPath(), position, bytesRead);
}
return bytesRead;
}
// otherwise, just say we got nothing - calling thread can do its own read
return 0;
}
/*
*
* Internal methods
*
*/
private void waitForProcess(final SeaweedInputStream stream, final long position) {
ReadBuffer readBuf;
synchronized (this) {
clearFromReadAheadQueue(stream, position);
readBuf = getFromList(inProgressList, stream, position);
}
if (readBuf != null) { // if in in-progress queue, then block for it
try {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("got a relevant read buffer for file {} offset {} buffer idx {}",
stream.getPath(), readBuf.getOffset(), readBuf.getBufferindex());
}
readBuf.getLatch().await(); // blocking wait on the caller stream's thread
// Note on correctness: readBuf gets out of inProgressList only in 1 place: after worker thread
// is done processing it (in doneReading). There, the latch is set after removing the buffer from
// inProgressList. So this latch is safe to be outside the synchronized block.
// Putting it in synchronized would result in a deadlock, since this thread would be holding the lock
// while waiting, so no one will be able to change any state. If this becomes more complex in the future,
// then the latch cane be removed and replaced with wait/notify whenever inProgressList is touched.
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("latch done for file {} buffer idx {} length {}",
stream.getPath(), readBuf.getBufferindex(), readBuf.getLength());
}
}
}
/**
* If any buffer in the completedlist can be reclaimed then reclaim it and return the buffer to free list.
* The objective is to find just one buffer - there is no advantage to evicting more than one.
*
* @return whether the eviction succeeeded - i.e., were we able to free up one buffer
*/
private synchronized boolean tryEvict() {
ReadBuffer nodeToEvict = null;
if (completedReadList.size() <= 0) {
return false; // there are no evict-able buffers
}
// first, try buffers where all bytes have been consumed (approximated as first and last bytes consumed)
for (ReadBuffer buf : completedReadList) {
if (buf.isFirstByteConsumed() && buf.isLastByteConsumed()) {
nodeToEvict = buf;
break;
}
}
if (nodeToEvict != null) {
return evict(nodeToEvict);
}
// next, try buffers where any bytes have been consumed (may be a bad idea? have to experiment and see)
for (ReadBuffer buf : completedReadList) {
if (buf.isAnyByteConsumed()) {
nodeToEvict = buf;
break;
}
}
if (nodeToEvict != null) {
return evict(nodeToEvict);
}
// next, try any old nodes that have not been consumed
long earliestBirthday = Long.MAX_VALUE;
for (ReadBuffer buf : completedReadList) {
if (buf.getTimeStamp() < earliestBirthday) {
nodeToEvict = buf;
earliestBirthday = buf.getTimeStamp();
}
}
if ((currentTimeMillis() - earliestBirthday > THRESHOLD_AGE_MILLISECONDS) && (nodeToEvict != null)) {
return evict(nodeToEvict);
}
// nothing can be evicted
return false;
}
private boolean evict(final ReadBuffer buf) {
freeList.push(buf.getBufferindex());
completedReadList.remove(buf);
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("Evicting buffer idx {}; was used for file {} offset {} length {}",
buf.getBufferindex(), buf.getStream().getPath(), buf.getOffset(), buf.getLength());
}
return true;
}
private boolean isAlreadyQueued(final SeaweedInputStream stream, final long requestedOffset) {
// returns true if any part of the buffer is already queued
return (isInList(readAheadQueue, stream, requestedOffset)
|| isInList(inProgressList, stream, requestedOffset)
|| isInList(completedReadList, stream, requestedOffset));
}
private boolean isInList(final Collection<ReadBuffer> list, final SeaweedInputStream stream, final long requestedOffset) {
return (getFromList(list, stream, requestedOffset) != null);
}
private ReadBuffer getFromList(final Collection<ReadBuffer> list, final SeaweedInputStream stream, final long requestedOffset) {
for (ReadBuffer buffer : list) {
if (buffer.getStream() == stream) {
if (buffer.getStatus() == ReadBufferStatus.AVAILABLE
&& requestedOffset >= buffer.getOffset()
&& requestedOffset < buffer.getOffset() + buffer.getLength()) {
return buffer;
} else if (requestedOffset >= buffer.getOffset()
&& requestedOffset < buffer.getOffset() + buffer.getRequestedLength()) {
return buffer;
}
}
}
return null;
}
private void clearFromReadAheadQueue(final SeaweedInputStream stream, final long requestedOffset) {
ReadBuffer buffer = getFromList(readAheadQueue, stream, requestedOffset);
if (buffer != null) {
readAheadQueue.remove(buffer);
notifyAll(); // lock is held in calling method
freeList.push(buffer.getBufferindex());
}
}
private int getBlockFromCompletedQueue(final SeaweedInputStream stream, final long position, final int length,
final byte[] buffer) {
ReadBuffer buf = getFromList(completedReadList, stream, position);
if (buf == null || position >= buf.getOffset() + buf.getLength()) {
return 0;
}
int cursor = (int) (position - buf.getOffset());
int availableLengthInBuffer = buf.getLength() - cursor;
int lengthToCopy = Math.min(length, availableLengthInBuffer);
System.arraycopy(buf.getBuffer(), cursor, buffer, 0, lengthToCopy);
if (cursor == 0) {
buf.setFirstByteConsumed(true);
}
if (cursor + lengthToCopy == buf.getLength()) {
buf.setLastByteConsumed(true);
}
buf.setAnyByteConsumed(true);
return lengthToCopy;
}
/*
*
* ReadBufferWorker-thread-facing methods
*
*/
/**
* ReadBufferWorker thread calls this to get the next buffer that it should work on.
*
* @return {@link ReadBuffer}
* @throws InterruptedException if thread is interrupted
*/
ReadBuffer getNextBlockToRead() throws InterruptedException {
ReadBuffer buffer = null;
synchronized (this) {
//buffer = readAheadQueue.take(); // blocking method
while (readAheadQueue.size() == 0) {
wait();
}
buffer = readAheadQueue.remove();
notifyAll();
if (buffer == null) {
return null; // should never happen
}
buffer.setStatus(ReadBufferStatus.READING_IN_PROGRESS);
inProgressList.add(buffer);
}
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("ReadBufferWorker picked file {} for offset {}",
buffer.getStream().getPath(), buffer.getOffset());
}
return buffer;
}
/**
* ReadBufferWorker thread calls this method to post completion.
*
* @param buffer the buffer whose read was completed
* @param result the {@link ReadBufferStatus} after the read operation in the worker thread
* @param bytesActuallyRead the number of bytes that the worker thread was actually able to read
*/
void doneReading(final ReadBuffer buffer, final ReadBufferStatus result, final int bytesActuallyRead) {
if (LOGGER.isTraceEnabled()) {
LOGGER.trace("ReadBufferWorker completed file {} for offset {} bytes {}",
buffer.getStream().getPath(), buffer.getOffset(), bytesActuallyRead);
}
synchronized (this) {
inProgressList.remove(buffer);
if (result == ReadBufferStatus.AVAILABLE && bytesActuallyRead > 0) {
buffer.setStatus(ReadBufferStatus.AVAILABLE);
buffer.setTimeStamp(currentTimeMillis());
buffer.setLength(bytesActuallyRead);
completedReadList.add(buffer);
} else {
freeList.push(buffer.getBufferindex());
// buffer should go out of scope after the end of the calling method in ReadBufferWorker, and eligible for GC
}
}
//outside the synchronized, since anyone receiving a wake-up from the latch must see safe-published results
buffer.getLatch().countDown(); // wake up waiting threads (if any)
}
/**
* Similar to System.currentTimeMillis, except implemented with System.nanoTime().
* System.currentTimeMillis can go backwards when system clock is changed (e.g., with NTP time synchronization),
* making it unsuitable for measuring time intervals. nanotime is strictly monotonically increasing per CPU core.
* Note: it is not monotonic across Sockets, and even within a CPU, its only the
* more recent parts which share a clock across all cores.
*
* @return current time in milliseconds
*/
private long currentTimeMillis() {
return System.nanoTime() / 1000 / 1000;
}
}

29
other/java/hdfs3/src/main/java/seaweed/hdfs/ReadBufferStatus.java
View File

@ -1,29 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
/**
* The ReadBufferStatus for Rest AbfsClient
*/
public enum ReadBufferStatus {
NOT_AVAILABLE, // buffers sitting in readaheadqueue have this stats
READING_IN_PROGRESS, // reading is in progress on this buffer. Buffer should be in inProgressList
AVAILABLE, // data is available in buffer. It should be in completedList
READ_FAILED // read completed, but failed.
}

70
other/java/hdfs3/src/main/java/seaweed/hdfs/ReadBufferWorker.java
View File

@ -1,70 +0,0 @@
/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package seaweed.hdfs;
import java.util.concurrent.CountDownLatch;
class ReadBufferWorker implements Runnable {
protected static final CountDownLatch UNLEASH_WORKERS = new CountDownLatch(1);
private int id;
ReadBufferWorker(final int id) {
this.id = id;
}
/**
* return the ID of ReadBufferWorker.
*/
public int getId() {
return this.id;
}
/**
* Waits until a buffer becomes available in ReadAheadQueue.
* Once a buffer becomes available, reads the file specified in it and then posts results back to buffer manager.
* Rinse and repeat. Forever.
*/
public void run() {
try {
UNLEASH_WORKERS.await();
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
}
ReadBufferManager bufferManager = ReadBufferManager.getBufferManager();
ReadBuffer buffer;
while (true) {
try {
buffer = bufferManager.getNextBlockToRead(); // blocks, until a buffer is available for this thread
} catch (InterruptedException ex) {
Thread.currentThread().interrupt();
return;
}
if (buffer != null) {
try {
// do the actual read, from the file.
int bytesRead = buffer.getStream().readRemote(buffer.getOffset(), buffer.getBuffer(), 0, buffer.getRequestedLength());
bufferManager.doneReading(buffer, ReadBufferStatus.AVAILABLE, bytesRead); // post result back to ReadBufferManager
} catch (Exception ex) {
bufferManager.doneReading(buffer, ReadBufferStatus.READ_FAILED, 0);
}
}
}
}
}

4
other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedFileSystemStore.java
View File

@ -212,7 +212,6 @@ public class SeaweedFileSystemStore {
LOG.debug("openFileForRead path:{} bufferSize:{}", path, bufferSize);
int readAheadQueueDepth = 2;
FilerProto.Entry entry = lookupEntry(path);
if (entry == null) {
@ -223,8 +222,7 @@ public class SeaweedFileSystemStore {
statistics,
path.toUri().getPath(),
entry,
bufferSize,
readAheadQueueDepth);
bufferSize);
}
public void setOwner(Path path, String owner, String group) {

169
other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedInputStream.java
View File

@ -27,16 +27,9 @@ public class SeaweedInputStream extends FSInputStream {
private final List<SeaweedRead.VisibleInterval> visibleIntervalList;
private final long contentLength;
private final int bufferSize; // default buffer size
private final int readAheadQueueDepth; // initialized in constructor
private final boolean readAheadEnabled; // whether enable readAhead;
private byte[] buffer = null; // will be initialized on first use
private long position = 0; // cursor of the file
private long fCursor = 0; // cursor of buffer within file - offset of next byte to read from remote server
private long fCursorAfterLastRead = -1;
private int bCursor = 0; // cursor of read within buffer - offset of next byte to be returned from buffer
private int limit = 0; // offset of next byte to be read into buffer from service (i.e., upper marker+1
// of valid bytes in buffer)
private boolean closed = false;
public SeaweedInputStream(
@ -44,16 +37,13 @@ public class SeaweedInputStream extends FSInputStream {
final Statistics statistics,
final String path,
final FilerProto.Entry entry,
final int bufferSize,
final int readAheadQueueDepth) {
final int bufferSize) {
this.filerGrpcClient = filerGrpcClient;
this.statistics = statistics;
this.path = path;
this.entry = entry;
this.contentLength = SeaweedRead.totalSize(entry.getChunksList());
this.bufferSize = bufferSize;
this.readAheadQueueDepth = (readAheadQueueDepth >= 0) ? readAheadQueueDepth : Runtime.getRuntime().availableProcessors();
this.readAheadEnabled = true;
this.visibleIntervalList = SeaweedRead.nonOverlappingVisibleIntervals(entry.getChunksList());
@ -78,122 +68,7 @@ public class SeaweedInputStream extends FSInputStream {
@Override
public synchronized int read(final byte[] b, final int off, final int len) throws IOException {
int currentOff = off;
int currentLen = len;
int lastReadBytes;
int totalReadBytes = 0;
do {
lastReadBytes = readOneBlock(b, currentOff, currentLen);
if (lastReadBytes > 0) {
currentOff += lastReadBytes;
currentLen -= lastReadBytes;
totalReadBytes += lastReadBytes;
}
if (currentLen <= 0 || currentLen > b.length - currentOff) {
break;
}
} while (lastReadBytes > 0);
return totalReadBytes > 0 ? totalReadBytes : lastReadBytes;
}
private int readOneBlock(final byte[] b, final int off, final int len) throws IOException {
if (closed) {
throw new IOException(FSExceptionMessages.STREAM_IS_CLOSED);
}
Preconditions.checkNotNull(b);
if (len == 0) {
return 0;
}
if (this.available() == 0) {
return -1;
}
if (off < 0 || len < 0 || len > b.length - off) {
throw new IndexOutOfBoundsException();
}
//If buffer is empty, then fill the buffer.
if (bCursor == limit) {
//If EOF, then return -1
if (fCursor >= contentLength) {
return -1;
}
long bytesRead = 0;
//reset buffer to initial state - i.e., throw away existing data
bCursor = 0;
limit = 0;
if (buffer == null) {
buffer = new byte[bufferSize];
}
// Enable readAhead when reading sequentially
if (-1 == fCursorAfterLastRead || fCursorAfterLastRead == fCursor || b.length >= bufferSize) {
bytesRead = readInternal(fCursor, buffer, 0, bufferSize, false);
} else {
bytesRead = readInternal(fCursor, buffer, 0, b.length, true);
}
if (bytesRead == -1) {
return -1;
}
limit += bytesRead;
fCursor += bytesRead;
fCursorAfterLastRead = fCursor;
}
//If there is anything in the buffer, then return lesser of (requested bytes) and (bytes in buffer)
//(bytes returned may be less than requested)
int bytesRemaining = limit - bCursor;
int bytesToRead = Math.min(len, bytesRemaining);
System.arraycopy(buffer, bCursor, b, off, bytesToRead);
bCursor += bytesToRead;
if (statistics != null) {
statistics.incrementBytesRead(bytesToRead);
}
return bytesToRead;
}
private int readInternal(final long position, final byte[] b, final int offset, final int length,
final boolean bypassReadAhead) throws IOException {
if (readAheadEnabled && !bypassReadAhead) {
// try reading from read-ahead
if (offset != 0) {
throw new IllegalArgumentException("readahead buffers cannot have non-zero buffer offsets");
}
int receivedBytes;
// queue read-aheads
int numReadAheads = this.readAheadQueueDepth;
long nextSize;
long nextOffset = position;
while (numReadAheads > 0 && nextOffset < contentLength) {
nextSize = Math.min((long) bufferSize, contentLength - nextOffset);
ReadBufferManager.getBufferManager().queueReadAhead(this, nextOffset, (int) nextSize);
nextOffset = nextOffset + nextSize;
numReadAheads--;
}
// try reading from buffers first
receivedBytes = ReadBufferManager.getBufferManager().getBlock(this, position, length, b);
if (receivedBytes > 0) {
return receivedBytes;
}
// got nothing from read-ahead, do our own read now
receivedBytes = readRemote(position, b, offset, length);
return receivedBytes;
} else {
return readRemote(position, b, offset, length);
}
}
int readRemote(long position, byte[] b, int offset, int length) throws IOException {
if (position < 0) {
throw new IllegalArgumentException("attempting to read from negative offset");
}
@ -203,21 +78,30 @@ public class SeaweedInputStream extends FSInputStream {
if (b == null) {
throw new IllegalArgumentException("null byte array passed in to read() method");
}
if (offset >= b.length) {
if (off >= b.length) {
throw new IllegalArgumentException("offset greater than length of array");
}
if (length < 0) {
if (len < 0) {
throw new IllegalArgumentException("requested read length is less than zero");
}
if (length > (b.length - offset)) {
if (len > (b.length - off)) {
throw new IllegalArgumentException("requested read length is more than will fit after requested offset in buffer");
}
long bytesRead = SeaweedRead.read(filerGrpcClient, visibleIntervalList, position, b, offset, length);
long bytesRead = SeaweedRead.read(this.filerGrpcClient, this.visibleIntervalList, this.position, b, off, len);
if (bytesRead > Integer.MAX_VALUE) {
throw new IOException("Unexpected Content-Length");
}
if (bytesRead > 0) {
this.position += bytesRead;
if (statistics != null) {
statistics.incrementBytesRead(bytesRead);
}
}
return (int)bytesRead;
}
/**
@ -239,17 +123,8 @@ public class SeaweedInputStream extends FSInputStream {
throw new EOFException(FSExceptionMessages.CANNOT_SEEK_PAST_EOF);
}
if (n >= fCursor - limit && n <= fCursor) { // within buffer
bCursor = (int) (n - (fCursor - limit));
return;
}
this.position = n;
// next read will read from here
fCursor = n;
//invalidate buffer
limit = 0;
bCursor = 0;
}
@Override
@ -257,20 +132,19 @@ public class SeaweedInputStream extends FSInputStream {
if (closed) {
throw new IOException(FSExceptionMessages.STREAM_IS_CLOSED);
}
long currentPos = getPos();
if (currentPos == contentLength) {
if (this.position == contentLength) {
if (n > 0) {
throw new EOFException(FSExceptionMessages.CANNOT_SEEK_PAST_EOF);
}
}
long newPos = currentPos + n;
long newPos = this.position + n;
if (newPos < 0) {
newPos = 0;
n = newPos - currentPos;
n = newPos - this.position;
}
if (newPos > contentLength) {
newPos = contentLength;
n = newPos - currentPos;
n = newPos - this.position;
}
seek(newPos);
return n;
@ -321,7 +195,7 @@ public class SeaweedInputStream extends FSInputStream {
if (closed) {
throw new IOException(FSExceptionMessages.STREAM_IS_CLOSED);
}
return fCursor - limit + bCursor;
return position;
}
/**
@ -338,7 +212,6 @@ public class SeaweedInputStream extends FSInputStream {
@Override
public synchronized void close() throws IOException {
closed = true;
buffer = null; // de-reference the buffer so it can be GC'ed sooner
}
/**