[GitHub] [hudi] danny0405 commented on a diff in pull request #8404: [HUDI-6049] split_reader don't checkpoint before consuming all splits

["danny0405 (via GitHub)" <gi...@apache.org>]

danny0405 commented on code in PR #8404:
URL: https://github.com/apache/hudi/pull/8404#discussion_r1161556062


##########
hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/source/SplitProcessThread.java:
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@@ -0,0 +1,127 @@
+/*
+ * 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.hudi.source;
+
+import org.apache.flink.streaming.api.functions.source.SourceFunction;
+import org.apache.flink.table.data.RowData;
+import org.apache.flink.util.function.ThrowingRunnable;
+import org.apache.hudi.adapter.MailboxExecutorAdapter;
+import org.apache.hudi.adapter.RateLimiterAdapter;
+import org.apache.hudi.common.util.Option;
+import org.apache.hudi.configuration.FlinkOptions;
+import org.apache.hudi.table.format.mor.MergeOnReadInputFormat;
+import org.apache.hudi.table.format.mor.MergeOnReadInputSplit;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.util.Queue;
+
+/**
+ *  A separate thread to process splits. Can control read rate by FlinkOptions.READ_RATE_LIMIT
+ */
+public class SplitProcessThread extends Thread {
+
+  private static final Logger LOG = LoggerFactory.getLogger(SplitProcessThread.class);
+  private volatile boolean running = true;
+  private transient Queue<MergeOnReadInputSplit> splits;
+
+  private final MailboxExecutorAdapter executor;
+
+  private MergeOnReadInputFormat format;
+
+  private transient SourceFunction.SourceContext<RowData> sourceContext;
+
+  private transient ThrowingRunnable<? extends Exception> exceptionHandler;
+  private transient Option<RateLimiterAdapter> rateLimiter;
+
+  public SplitProcessThread(Queue<MergeOnReadInputSplit> splits, MailboxExecutorAdapter executor, MergeOnReadInputFormat format,
+                            SourceFunction.SourceContext<RowData> sourceContext, ThrowingRunnable<? extends Exception> exceptionHandler,
+                            int indexOfThisSubtask, int numberOfParallelSubtasks) {
+    setName(String.format("split-process-thread (%s/%s)", indexOfThisSubtask + 1, numberOfParallelSubtasks));
+    this.splits = splits;
+    this.executor = executor;
+    this.format = format;
+    this.sourceContext = sourceContext;
+    this.exceptionHandler = exceptionHandler;
+    long rate = format.getConf().getLong(FlinkOptions.READ_RATE_LIMIT);
+    this.rateLimiter = rate > 0 ? Option.of(RateLimiterAdapter.create(rate)) : Option.empty();
+  }
+
+  @Override
+  public void run() {
+    while (running) {

Review Comment:
   We lost the exactly-once semantics if the consumption is taking place in another thread, that is, when the checkpoint barrier passed by, the consumption offset is not managed synchonously within the state-backend, we consume like 2048 records per-batch, and the discrepancy can be within range [0, 2048].



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