[GitHub] [pulsar] poorbarcode commented on a diff in pull request #16428: [improve] [transaction] [PIP-160] Make transactions work more efficiently by aggregation operation for transaction log and pending ack store

[GitBox <gi...@apache.org>]

poorbarcode commented on code in PR #16428:
URL: https://github.com/apache/pulsar/pull/16428#discussion_r915872200


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pulsar-transaction/coordinator/src/main/java/org/apache/pulsar/transaction/coordinator/impl/TxLogBufferedWriter.java:
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@@ -0,0 +1,439 @@
+/**
+ * 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.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;
+
+/***
+ * 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 TxLogBufferedWriter<T> implements AsyncCallbacks.AddEntryCallback, Closeable {
+
+    /**
+     * Enable or disabled the batch feature, will use Managed Ledger directly and without batching when disabled.
+     */
+    private final boolean batchEnabled;
+
+    private final ManagedLedger managedLedger;
+
+    private final OrderedExecutor orderedExecutor;
+
+    private final ScheduledExecutorService scheduledExecutorService;
+
+    /** 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 writeMaxDelayInMillis;
+
+    /** Data cached in the current batch. Will reset to null after each batched writes. **/
+    private ArrayList<T> dataArray;
+
+    /**
+     * Parameters of {@link #asyncAddData} cached in the current batch. Will reset to null after each batched writes.
+     */
+    private ArrayList<AsyncAddArgs> asyncAddArgsList;
+
+    /** Bytes size of data in current batch. Will reset to 0 after each batched writes. **/
+    private long bytesSize;
+
+    public TxLogBufferedWriter(ManagedLedger managedLedger, OrderedExecutor orderedExecutor,
+                               ScheduledExecutorService scheduledExecutorService, DataSerializer<T> dataSerializer,
+                               boolean batchEnabled){
+        this(managedLedger, orderedExecutor, scheduledExecutorService, dataSerializer,
+                512, 1024 * 1024 * 4, 1, batchEnabled);
+    }
+
+    /**
+     * 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 writeMaxDelayInMillis 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 TxLogBufferedWriter(ManagedLedger managedLedger, OrderedExecutor orderedExecutor,
+                               ScheduledExecutorService scheduledExecutorService, DataSerializer<T> dataSerializer,
+                               int batchedWriteMaxRecords, int batchedWriteMaxSize, int writeMaxDelayInMillis,
+                               boolean batchEnabled){
+        this.batchEnabled = batchEnabled;
+        this.managedLedger = managedLedger;
+        this.orderedExecutor = orderedExecutor;
+        this.scheduledExecutorService = scheduledExecutorService;
+        this.dataSerializer = dataSerializer;
+        this.batchedWriteMaxRecords = batchedWriteMaxRecords;
+        this.batchedWriteMaxSize = batchedWriteMaxSize;
+        this.writeMaxDelayInMillis = writeMaxDelayInMillis;
+        // scheduler task.
+        if (batchEnabled) {
+            this.scheduledFuture = this.scheduledExecutorService.scheduleAtFixedRate(this::trigFlush,
+                    writeMaxDelayInMillis, writeMaxDelayInMillis, TimeUnit.MICROSECONDS);
+        }
+    }
+
+    /**
+     * 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 AsyncCallbacks.AddEntryCallback#addComplete(Position, ByteBuf, Object)} when
+     *                 add complete.
+     *                 Note: When {@link #batchEnabled} == false, the param-byteBuf of {@param callback} will be null.
+     *                 Will call {@link AsyncCallbacks.AddEntryCallback#addFailed(ManagedLedgerException, Object)} when
+     *                 add failure.
+     * @throws ManagedLedgerException
+     */
+    public void asyncAddData(T data, AsyncCallbacks.AddEntryCallback callback, Object ctx){
+        if (!batchEnabled){
+            ByteBuf byteBuf = dataSerializer.serialize(data);
+            managedLedger.asyncAddEntry(byteBuf, DisabledBatchCallback.INSTANCE, Triple.of(byteBuf, callback, ctx));
+            return;
+        }
+        orderedExecutor.executeOrdered(managedLedger.getName(), () -> asyncAddData0(data, callback, ctx));
+    }
+
+    private void asyncAddData0(T data, AsyncCallbacks.AddEntryCallback callback, Object ctx){

Review Comment:
   OK. I have modified this method name to "internalAsyncAddData"



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