HeimingZ commented on a change in pull request #5320: URL: https://github.com/apache/iotdb/pull/5320#discussion_r839360788
########## File path: server/src/main/java/org/apache/iotdb/db/wal/buffer/WALBuffer.java ########## @@ -0,0 +1,435 @@ +/* + * 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 org.apache.iotdb.db.wal.buffer; + +import org.apache.iotdb.commons.concurrent.IoTDBThreadPoolFactory; +import org.apache.iotdb.commons.concurrent.ThreadName; +import org.apache.iotdb.db.conf.IoTDBConfig; +import org.apache.iotdb.db.conf.IoTDBDescriptor; +import org.apache.iotdb.db.qp.physical.crud.DeletePlan; +import org.apache.iotdb.db.utils.MmapUtil; +import org.apache.iotdb.db.wal.exception.WALNodeClosedException; +import org.apache.iotdb.db.wal.utils.WALMode; +import org.apache.iotdb.db.wal.utils.listener.WALFlushListener; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.FileNotFoundException; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.MappedByteBuffer; +import java.util.Collections; +import java.util.LinkedList; +import java.util.List; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.locks.Condition; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; + +/** + * This buffer guarantees the concurrent safety and uses double buffers mechanism to accelerate + * writes and avoid waiting for buffer syncing to disk. + */ +public class WALBuffer extends AbstractWALBuffer { + private static final Logger logger = LoggerFactory.getLogger(WALBuffer.class); + private static final IoTDBConfig config = IoTDBDescriptor.getInstance().getConfig(); + private static final int WAL_BUFFER_SIZE = config.getWalBufferSize(); + private static final long FSYNC_WAL_DELAY_IN_MS = config.getFsyncWalDelayInMs(); + /** default delay time of each serialize task when wal mode is async */ + public static final long ASYNC_WAL_DELAY_IN_MS = 100; + /** Maximum number of WALEdits in one serialize task when wal mode is sync */ + public static final int SYNC_BATCH_SIZE_LIMIT = 100; + /** Maximum number of WALEdits in the blocking queue */ + public static final int SIZE_LIMIT = 10_000; + /** notify serializeThread to stop */ + private static final WALEdit CLOSE_SIGNAL = new WALEdit(-1, new DeletePlan()); + + /** whether close method is called */ + private volatile boolean isClosed = false; + /** WALEdits */ + private final BlockingQueue<WALEdit> walEdits = new ArrayBlockingQueue<>(SIZE_LIMIT); + /** lock to provide synchronization for double buffers mechanism, protecting buffers status */ + private final Lock buffersLock = new ReentrantLock(); + /** condition to guarantee correctness of switching buffers */ + private final Condition idleBufferReadyCondition = buffersLock.newCondition(); + // region these variables should be protected by buffersLock + /** two buffers switch between three statuses (there is always 1 buffer working) */ + // buffer in working status, only updated by serializeThread + private volatile ByteBuffer workingBuffer; + // buffer in idle status + private volatile ByteBuffer idleBuffer; + // buffer in syncing status, serializeThread makes sure no more writes to syncingBuffer + private volatile ByteBuffer syncingBuffer; + // endregion + /** single thread to serialize WALEdit to workingBuffer */ + private final ExecutorService serializeThread; + /** single thread to sync syncingBuffer to disk */ + private final ExecutorService syncBufferThread; + + public WALBuffer(String identifier, String logDirectory) throws FileNotFoundException { + super(identifier, logDirectory); + allocateBuffers(); + serializeThread = + IoTDBThreadPoolFactory.newSingleThreadExecutor( + ThreadName.WAL_SERIALIZE.getName() + "(node-" + identifier + ")"); + syncBufferThread = + IoTDBThreadPoolFactory.newSingleThreadExecutor( + ThreadName.WAL_SYNC.getName() + "(node-" + identifier + ")"); + // start receiving serialize tasks + serializeThread.submit(new SerializeTask()); + } + + private void allocateBuffers() { + try { + workingBuffer = ByteBuffer.allocateDirect(WAL_BUFFER_SIZE / 2); + idleBuffer = ByteBuffer.allocateDirect(WAL_BUFFER_SIZE / 2); + } catch (OutOfMemoryError e) { + logger.error("Fail to allocate wal node-{}'s buffer because out of memory.", identifier, e); + close(); + throw e; + } + } + + @Override + public void write(WALEdit edit) { + if (isClosed) { + logger.error( + "Fail to write WALEdit into wal node-{} because this node is closed.", identifier); + edit.getWalFlushListener().fail(new WALNodeClosedException(identifier)); + return; + } + // only add this WALEdit to queue + try { + walEdits.put(edit); + } catch (InterruptedException e) { + logger.warn("Interrupted when waiting for adding WalEdit to buffer."); + Thread.currentThread().interrupt(); + } + } + + // region Task of serializeThread + /** This task serializes WALEdit to workingBuffer and will call fsync at last. */ + private class SerializeTask implements Runnable { + private final IWALByteBufferView byteBufferVew = new ByteBufferView(); + private final List<WALFlushListener> fsyncListeners = new LinkedList<>(); + + @Override + public void run() { + try { + serialize(); + } finally { + serializeThread.submit(new SerializeTask()); + } + } + + /** In order to control memory usage of blocking queue, get 1 and then serialize 1 */ + private void serialize() { + // try to get first WALEdit with blocking interface + int batchSize = 0; + try { + WALEdit edit = walEdits.take(); + try { + if (edit != CLOSE_SIGNAL) { + edit.serialize(byteBufferVew); + ++batchSize; + fsyncListeners.add(edit.getWalFlushListener()); + } + } catch (Exception e) { + logger.error( + "Fail to serialize WALEdit to wal node-{}'s buffer, discard it.", identifier, e); + edit.getWalFlushListener().fail(e); + } + } catch (InterruptedException e) { + logger.warn( + "Interrupted when waiting for taking WALEdit from blocking queue to serialize."); + Thread.currentThread().interrupt(); + } + // for better fsync performance, sleep a while to enlarge write batch + if (FSYNC_WAL_DELAY_IN_MS > 0 || config.getWalMode() == WALMode.ASYNC) { + long sleepTime = FSYNC_WAL_DELAY_IN_MS > 0 ? FSYNC_WAL_DELAY_IN_MS : ASYNC_WAL_DELAY_IN_MS; + try { + Thread.sleep(sleepTime); + } catch (InterruptedException e) { + logger.warn("Interrupted when sleeping a while to enlarge wal write batch."); + Thread.currentThread().interrupt(); + } + } + // try to get more WALEdits with non-blocking interface to enlarge write batch + // control batch size in sync mode to return quickly + int bachSizeLimit = config.getWalMode() == WALMode.SYNC ? SYNC_BATCH_SIZE_LIMIT : SIZE_LIMIT; + while (walEdits.peek() != null && batchSize < bachSizeLimit) { + WALEdit edit = walEdits.poll(); + if (edit == null || edit == CLOSE_SIGNAL) { + break; + } else { + try { + edit.serialize(byteBufferVew); + } catch (Exception e) { + logger.error( + "Fail to serialize WALEdit to wal node-{}'s buffer, discard it.", identifier, e); + edit.getWalFlushListener().fail(e); + continue; + } + ++batchSize; + fsyncListeners.add(edit.getWalFlushListener()); + } + } + // call fsync at last and set fsyncListeners + if (batchSize > 0) { + fsyncWorkingBuffer(fsyncListeners); + } + } + } + + /** + * This view uses workingBuffer lock-freely because workingBuffer is only updated by + * serializeThread and this class is only used by serializeThread. + */ + private class ByteBufferView implements IWALByteBufferView { + private void ensureEnoughSpace(int bytesNum) { + if (workingBuffer.remaining() < bytesNum) { + rollBuffer(); + } + } + + private void rollBuffer() { + syncWorkingBuffer(); + } + + @Override + public void put(byte b) { + ensureEnoughSpace(Byte.BYTES); + workingBuffer.put(b); + } + + @Override + public void put(byte[] src) { + int offset = 0; + while (true) { + int leftCapacity = workingBuffer.remaining(); + int needCapacity = src.length - offset; + if (leftCapacity >= needCapacity) { + workingBuffer.put(src, offset, needCapacity); + break; + } else { + workingBuffer.put(src, offset, leftCapacity); + offset += leftCapacity; + rollBuffer(); + } + } + } + + @Override + public void putChar(char value) { + ensureEnoughSpace(Character.BYTES); + workingBuffer.putChar(value); + } + + @Override + public void putShort(short value) { + ensureEnoughSpace(Short.BYTES); + workingBuffer.putShort(value); + } + + @Override + public void putInt(int value) { + ensureEnoughSpace(Integer.BYTES); + workingBuffer.putInt(value); + } + + @Override + public void putLong(long value) { + ensureEnoughSpace(Long.BYTES); + workingBuffer.putLong(value); + } + + @Override + public void putFloat(float value) { + ensureEnoughSpace(Float.BYTES); + workingBuffer.putFloat(value); + } + + @Override + public void putDouble(double value) { + ensureEnoughSpace(Double.BYTES); + workingBuffer.putDouble(value); + } + } + + /** Notice: this method only called when buffer is exhausted by SerializeTask. */ + private void syncWorkingBuffer() { + switchIdleBufferToWorking(); + syncBufferThread.submit(new SyncBufferTask(false)); + } + + /** Notice: this method only called at the last of SerializeTask. */ + private void fsyncWorkingBuffer(List<WALFlushListener> fsyncListeners) { + switchIdleBufferToWorking(); + syncBufferThread.submit(new SyncBufferTask(true, fsyncListeners)); + } + + // only called by serializeThread + private void switchIdleBufferToWorking() { Review comment: Fixed. ########## File path: server/src/main/java/org/apache/iotdb/db/wal/buffer/WALBuffer.java ########## @@ -0,0 +1,435 @@ +/* + * 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 org.apache.iotdb.db.wal.buffer; + +import org.apache.iotdb.commons.concurrent.IoTDBThreadPoolFactory; +import org.apache.iotdb.commons.concurrent.ThreadName; +import org.apache.iotdb.db.conf.IoTDBConfig; +import org.apache.iotdb.db.conf.IoTDBDescriptor; +import org.apache.iotdb.db.qp.physical.crud.DeletePlan; +import org.apache.iotdb.db.utils.MmapUtil; +import org.apache.iotdb.db.wal.exception.WALNodeClosedException; +import org.apache.iotdb.db.wal.utils.WALMode; +import org.apache.iotdb.db.wal.utils.listener.WALFlushListener; + +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.io.FileNotFoundException; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.nio.MappedByteBuffer; +import java.util.Collections; +import java.util.LinkedList; +import java.util.List; +import java.util.concurrent.ArrayBlockingQueue; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.locks.Condition; +import java.util.concurrent.locks.Lock; +import java.util.concurrent.locks.ReentrantLock; + +/** + * This buffer guarantees the concurrent safety and uses double buffers mechanism to accelerate + * writes and avoid waiting for buffer syncing to disk. + */ +public class WALBuffer extends AbstractWALBuffer { + private static final Logger logger = LoggerFactory.getLogger(WALBuffer.class); + private static final IoTDBConfig config = IoTDBDescriptor.getInstance().getConfig(); + private static final int WAL_BUFFER_SIZE = config.getWalBufferSize(); + private static final long FSYNC_WAL_DELAY_IN_MS = config.getFsyncWalDelayInMs(); + /** default delay time of each serialize task when wal mode is async */ + public static final long ASYNC_WAL_DELAY_IN_MS = 100; + /** Maximum number of WALEdits in one serialize task when wal mode is sync */ + public static final int SYNC_BATCH_SIZE_LIMIT = 100; + /** Maximum number of WALEdits in the blocking queue */ + public static final int SIZE_LIMIT = 10_000; Review comment: Fixed. -- This is an automated message from the Apache Git Service. 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