poorbarcode commented on code in PR #16428: URL: https://github.com/apache/pulsar/pull/16428#discussion_r920705224
########## pulsar-transaction/coordinator/src/main/java/org/apache/pulsar/transaction/coordinator/impl/TxnLogBufferedWriter.java: ########## @@ -0,0 +1,483 @@ +/** + * 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.pulsar.transaction.coordinator.impl; + +import io.netty.buffer.ByteBuf; +import io.netty.buffer.Unpooled; +import io.netty.util.Recycler; +import java.io.Closeable; +import java.util.ArrayList; +import java.util.Objects; +import java.util.UUID; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.ScheduledFuture; +import java.util.concurrent.TimeUnit; +import lombok.Getter; +import lombok.ToString; +import lombok.extern.slf4j.Slf4j; +import org.apache.bookkeeper.common.util.OrderedExecutor; +import org.apache.bookkeeper.mledger.AsyncCallbacks; +import org.apache.bookkeeper.mledger.ManagedLedger; +import org.apache.bookkeeper.mledger.ManagedLedgerException; +import org.apache.bookkeeper.mledger.Position; +import org.apache.bookkeeper.mledger.impl.PositionImpl; +import org.apache.bookkeeper.util.SafeRunnable; +import org.apache.commons.lang3.tuple.Triple; +import org.apache.pulsar.common.allocator.PulsarByteBufAllocator; +import org.apache.pulsar.common.util.collections.BitSetRecyclable; + +/*** + * See PIP-160: https://github.com/apache/pulsar/issues/15516. + * Buffer requests and flush to Managed Ledger. Transaction Log Store And Pending Ack Store will no longer write to + * Managed Ledger directly, Change to using this class to write Ledger data. + * Caches “write requests” for a certain number or a certain size of request data and then writes them to the + * Managed Ledger in one go. After Managed Ledger has written complete, responds to each request-caller. In this + * process, Managed Ledger doesn't care how many records(or what to be written) in the Entry, it just treats them as + * a single block of data. + * The first write-request by transaction components will take a long time to receive a response, because we must wait + * for subsequent requests to accumulate enough data to actually start writing to the Managed Ledger. To control the + * maximum latency, we will mark the first request time for each batch, and additional timing triggers writes. + * You can enable or disabled the batch feature, will use Managed Ledger directly and without batching when disabled. + */ +@Slf4j +public class TxnLogBufferedWriter<T> implements AsyncCallbacks.AddEntryCallback, Closeable { + + public static final short BATCHED_ENTRY_DATA_PREFIX_MAGIC_NUMBER = 0x0e01; + + public static final short BATCHED_ENTRY_DATA_PREFIX_VERSION = 1; + + private static final ManagedLedgerException BUFFERED_WRITER_CLOSED_EXCEPTION = + new ManagedLedgerException.ManagedLedgerFencedException( + new Exception("Transaction log buffered write has closed") + ); + + /** + * Enable or disabled the batch feature, will use Managed Ledger directly and without batching when disabled. + */ + private final boolean batchEnabled; + + private final ManagedLedger managedLedger; + + /** All write operation will be executed on single thread. **/ + private final ExecutorService singleThreadExecutorForWrite; + + /** The serializer for the object which called by {@link #asyncAddData}. **/ + private final DataSerializer<T> dataSerializer; + + private ScheduledFuture<?> scheduledFuture; + + /** + * Caches “write requests” for a certain for a certain number, if reach this threshold, will trig Bookie writes. + */ + private final int batchedWriteMaxRecords; + + /** + * Caches “write requests” for a certain size of request data, if reach this threshold, will trig Bookie writes. + */ + private final int batchedWriteMaxSize; + + /** Maximum delay for writing to bookie for the earliest request in the batch. **/ + private final int batchedWriteMaxDelayInMillis; + + /** Data cached in the current batch. Will reset to null after each batched writes. **/ + private final ArrayList<T> dataArray; + + /** + * Parameters of {@link #asyncAddData} cached in the current batch. Will create a new one after each batched writes. + */ + private FlushContext flushContext; + + /** Bytes size of data in current batch. Will reset to 0 after each batched writes. **/ + private long bytesSize; + + /** The main purpose of state maintenance is to prevent written after close. **/ + private volatile State state; + + /** + * Constructor. + * @param dataSerializer The serializer for the object which called by {@link #asyncAddData}. + * @param batchedWriteMaxRecords Caches “write requests” for a certain number, if reach this threshold, will trig + * Bookie writes. + * @param batchedWriteMaxSize Caches “write requests” for a certain size of request data, if reach this threshold, + * will trig Bookie writes. + * @param batchedWriteMaxDelayInMillis Maximum delay for writing to bookie for the earliest request in the batch. + * @param batchEnabled Enable or disabled the batch feature, will use Managed Ledger directly and without batching + * when disabled. + */ + public TxnLogBufferedWriter(ManagedLedger managedLedger, OrderedExecutor orderedExecutor, + ScheduledExecutorService scheduledExecutorService, DataSerializer<T> dataSerializer, + int batchedWriteMaxRecords, int batchedWriteMaxSize, int batchedWriteMaxDelayInMillis, + boolean batchEnabled){ + this.batchEnabled = batchEnabled; + this.managedLedger = managedLedger; + this.singleThreadExecutorForWrite = orderedExecutor.chooseThread( + managedLedger.getName() == null ? UUID.randomUUID().toString() : managedLedger.getName()); + this.dataSerializer = dataSerializer; + this.batchedWriteMaxRecords = batchedWriteMaxRecords; + this.batchedWriteMaxSize = batchedWriteMaxSize; + this.batchedWriteMaxDelayInMillis = batchedWriteMaxDelayInMillis; + this.flushContext = FlushContext.newInstance(); + this.dataArray = new ArrayList<>(); + // scheduler task. + if (batchEnabled) { + this.scheduledFuture = scheduledExecutorService.scheduleAtFixedRate(this::trigFlush, + batchedWriteMaxDelayInMillis, batchedWriteMaxDelayInMillis, TimeUnit.MICROSECONDS); + } + this.state = State.RUNNING; + } + + /** + * Append a new entry to the end of a managed ledger. All writes will be performed in the same thread. + * @param data data entry to be persisted. + * @param callback Will call {@link AddDataCallback#addComplete(Position, Object)} when + * add complete. + * Will call {@link AddDataCallback#addFailed(ManagedLedgerException, Object)} when + * add failure. + * @throws ManagedLedgerException + */ + public void asyncAddData(T data, AddDataCallback callback, Object ctx){ + if (state == State.CLOSING || state == State.CLOSED){ + callback.addFailed(BUFFERED_WRITER_CLOSED_EXCEPTION, ctx); + return; + } + if (!batchEnabled){ + ByteBuf byteBuf = dataSerializer.serialize(data); + managedLedger.asyncAddEntry(byteBuf, DisabledBatchCallback.INSTANCE, Triple.of(byteBuf, callback, ctx)); + return; + } + singleThreadExecutorForWrite.execute(() -> internalAsyncAddData(data, callback, ctx)); + } + + private void internalAsyncAddData(T data, AddDataCallback callback, Object ctx){ + int len = dataSerializer.getSerializedSize(data); + if (len >= batchedWriteMaxSize){ + if (!flushContext.asyncAddArgsList.isEmpty()) { + doTrigFlush(true); + } + ByteBuf byteBuf = dataSerializer.serialize(data); + managedLedger.asyncAddEntry(byteBuf, DisabledBatchCallback.INSTANCE, Triple.of(byteBuf, callback, ctx)); + return; + } + // Add data. + this.dataArray.add(data); + // Add callback info. + AsyncAddArgs asyncAddArgs = AsyncAddArgs.newInstance(callback, ctx, System.currentTimeMillis()); + this.flushContext.asyncAddArgsList.add(asyncAddArgs); + // Calculate bytes-size. + this.bytesSize += len; + // trig flush. + doTrigFlush(false); + } + + /*** + * The serializer for the object which called by {@link #asyncAddData}. + */ + public interface DataSerializer<T>{ + + /** + * Calculate the number of bytes taken by {@param data} after serialization. + * @param data The object which called by {@link #asyncAddData}. + * @return The number of bytes taken after serialization. + */ + int getSerializedSize(T data); + + /** + * Serialize {@param data} to {@link ByteBuf}. The returned ByteBuf will be release once after writing to + * Bookie complete, and if you still need to use the ByteBuf, should call {@link ByteBuf#retain()} in + * {@link #serialize(Object)} implementation. + * @param data The object which called by {@link #asyncAddData}. + * @return byte buf. + */ + ByteBuf serialize(T data); + + /** + * Serialize {@param dataArray} to {@link ByteBuf}.. The returned ByteBuf will be release once after writing to + * Bookie complete, and if you still need to use the ByteBuf, should call {@link ByteBuf#retain()} in + * {@link #serialize(Object)} implementation. + * @param dataArray The objects which called by {@link #asyncAddData}. + * @return byte buf. + */ + ByteBuf serialize(ArrayList<T> dataArray); + + } + + /** + * Trigger write to bookie once, If the conditions are not met, nothing will be done. + */ + public void trigFlush(){ + singleThreadExecutorForWrite.execute(() -> doTrigFlush(false)); + } + + private void doTrigFlush(boolean force){ + if (flushContext.asyncAddArgsList.isEmpty()) { + return; + } + if (force){ + doFlush(); + return; + } + AsyncAddArgs firstAsyncAddArgs = flushContext.asyncAddArgsList.get(0); + if (System.currentTimeMillis() - firstAsyncAddArgs.addedTime > batchedWriteMaxDelayInMillis){ + doFlush(); + return; + } + if (this.flushContext.asyncAddArgsList.size() >= batchedWriteMaxRecords){ + doFlush(); + return; + } + if (this.bytesSize >= batchedWriteMaxSize){ + doFlush(); + } + } + + private void doFlush(){ + // Combine data. + ByteBuf prefix = PulsarByteBufAllocator.DEFAULT.buffer(4); + prefix.writeShort(BATCHED_ENTRY_DATA_PREFIX_MAGIC_NUMBER); + prefix.writeShort(BATCHED_ENTRY_DATA_PREFIX_VERSION); + ByteBuf actualContent = this.dataSerializer.serialize(this.dataArray); + ByteBuf pairByteBuf = Unpooled.wrappedUnmodifiableBuffer(prefix, actualContent); + // Flush. + managedLedger.asyncAddEntry(pairByteBuf, this, flushContext); + // Clear buffers. + this.dataArray.clear(); + this.flushContext = FlushContext.newInstance(); + this.bytesSize = 0; + } + + /** + * see {@link AsyncCallbacks.AddEntryCallback#addComplete(Position, ByteBuf, Object)}. + */ + @Override + public void addComplete(Position position, ByteBuf entryData, Object ctx) { + final FlushContext flushContext = (FlushContext) ctx; + try { + final int batchSize = flushContext.asyncAddArgsList.size(); + for (int batchIndex = 0; batchIndex < batchSize; batchIndex++) { + final AsyncAddArgs asyncAddArgs = flushContext.asyncAddArgsList.get(batchIndex); + BitSetRecyclable bitSetRecyclable = BitSetRecyclable.create(); + bitSetRecyclable.set(batchIndex); + long[] ackSet = bitSetRecyclable.toLongArray(); + bitSetRecyclable.recycle(); + final TxnBatchedPositionImpl txnBatchedPosition = new TxnBatchedPositionImpl(position, batchSize, + batchIndex, ackSet); + // Because this task already running at ordered task, so just "run". + SafeRunnable.safeRun(() -> { + asyncAddArgs.callback.addComplete(txnBatchedPosition, asyncAddArgs.ctx); + }).run(); + } + } finally { + entryData.release(); + flushContext.recycle(); + } + } + + /** + * see {@link AsyncCallbacks.AddEntryCallback#addFailed(ManagedLedgerException, Object)}. + */ + @Override + public void addFailed(ManagedLedgerException exception, Object ctx) { + final FlushContext flushContext = (FlushContext) ctx; + try { + for (int i = 0; i < flushContext.asyncAddArgsList.size(); i++) { + final AsyncAddArgs asyncAddArgs = flushContext.asyncAddArgsList.get(i); + // Because this task already running at ordered task, so just "run". + SafeRunnable.safeRun(() -> asyncAddArgs.callback.addFailed(exception, asyncAddArgs.ctx)).run(); + } + } finally { + flushContext.recycle(); + } + } + + /** + * Release resources and executing tasks. + */ + @Override + public void close() { + this.state = State.CLOSING; + singleThreadExecutorForWrite.execute(() -> { + if (!flushContext.asyncAddArgsList.isEmpty()) { + doTrigFlush(true); + } + }); + if (this.scheduledFuture != null) { + this.scheduledFuture.cancel(false); + } + this.state = State.CLOSED; + } + + /*** + * Holds the parameters of {@link #asyncAddData} for each callback after batch write finished. This object is + * designed to be reusable, so the recycle mechanism is used。 + */ + @ToString + public static class AsyncAddArgs { + + private static final Recycler<AsyncAddArgs> ASYNC_ADD_ARGS_RECYCLER = new Recycler<>() { + @Override + protected AsyncAddArgs newObject(Handle<AsyncAddArgs> handle) { + return new AsyncAddArgs(handle); + } + }; + + public static AsyncAddArgs newInstance(AddDataCallback callback, Object ctx, long addedTime){ + AsyncAddArgs asyncAddArgs = ASYNC_ADD_ARGS_RECYCLER.get(); + asyncAddArgs.callback = callback; + asyncAddArgs.ctx = ctx; + asyncAddArgs.addedTime = addedTime; + return asyncAddArgs; + } + + private AsyncAddArgs(Recycler.Handle<AsyncAddArgs> handle){ + this.handle = handle; + } + + private final Recycler.Handle<AsyncAddArgs> handle; + + /** Argument for {@link #asyncAddData(Object, AddDataCallback, Object)}. **/ + @Getter + private AddDataCallback callback; + + /** Argument for {@link #asyncAddData(Object, AddDataCallback, Object)}. **/ + @Getter + private Object ctx; + + /** Time of executed {@link #asyncAddData(Object, AddDataCallback, Object)}. **/ + @Getter + private long addedTime; + + } + + /*** + * The context for {@link ManagedLedger#asyncAddEntry(byte[], AsyncCallbacks.AddEntryCallback, Object)}, Holds the + * data array written in batches and callback parameters that need to be executed after batched write is complete. + */ + public static class FlushContext{ + + private static final Recycler<FlushContext> FLUSH_CONTEXT_RECYCLER = new Recycler<FlushContext>() { + @Override + protected FlushContext newObject(Handle<FlushContext> handle) { + return new FlushContext(handle); + } + }; + + private final Recycler.Handle<FlushContext> handle; + + /** Callback parameters for current batch. **/ + private final ArrayList<AsyncAddArgs> asyncAddArgsList; + + public FlushContext(Recycler.Handle<FlushContext> handle){ Review Comment: Fixed. -- This is an automated message from the Apache Git Service. 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