[HUDI-2677] Add DFS based message queue for flink writer[part3] (#4961)

hudi-flink/src/main/java/org/apache/hudi/sink/CleanFunction.java

@@ -62,9 +62,7 @@ public class CleanFunction<T> extends AbstractRichFunction
   public void open(Configuration parameters) throws Exception {
     super.open(parameters);
     if (conf.getBoolean(FlinkOptions.CLEAN_ASYNC_ENABLED)) {
-      // do not use the remote filesystem view because the async cleaning service
+      this.writeClient = StreamerUtil.createWriteClient(conf, getRuntimeContext());
-      // local timeline is very probably to fall behind with the remote one.
-      this.writeClient = StreamerUtil.createWriteClient(conf, getRuntimeContext(), false);
       this.executor = NonThrownExecutor.builder(LOG).waitForTasksFinish(true).build();
 
       if (conf.getString(FlinkOptions.OPERATION).equals(WriteOperationType.INSERT_OVERWRITE_TABLE.value())) {

hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteOperatorCoordinator.java

@@ -32,6 +32,7 @@ import org.apache.hudi.configuration.OptionsResolver;
 import org.apache.hudi.exception.HoodieException;
 import org.apache.hudi.sink.event.CommitAckEvent;
 import org.apache.hudi.sink.event.WriteMetadataEvent;
+import org.apache.hudi.sink.meta.CkpMetadata;
 import org.apache.hudi.sink.utils.HiveSyncContext;
 import org.apache.hudi.sink.utils.NonThrownExecutor;
 import org.apache.hudi.util.CompactionUtil;
@@ -137,6 +138,16 @@ public class StreamWriteOperatorCoordinator
    */
   private transient TableState tableState;
 
+  /**
+   * The checkpoint metadata.
+   */
+  private CkpMetadata ckpMetadata;
+
+  /**
+   * Current checkpoint.
+   */
+  private long checkpointId = -1;
+
   /**
    * Constructs a StreamingSinkOperatorCoordinator.
    *
@@ -175,6 +186,8 @@ public class StreamWriteOperatorCoordinator
     if (tableState.syncMetadata) {
       initMetadataSync();
     }
+    this.ckpMetadata = CkpMetadata.getInstance(this.metaClient.getFs(), metaClient.getBasePath());
+    this.ckpMetadata.bootstrap(this.metaClient);
   }
 
   @Override
@@ -192,10 +205,14 @@ public class StreamWriteOperatorCoordinator
       writeClient.close();
     }
     this.eventBuffer = null;
+    if (this.ckpMetadata != null) {
+      this.ckpMetadata.close();
+    }
   }
 
   @Override
   public void checkpointCoordinator(long checkpointId, CompletableFuture<byte[]> result) {
+    this.checkpointId = checkpointId;
     executor.execute(
         () -> {
           try {
@@ -238,6 +255,15 @@ public class StreamWriteOperatorCoordinator
     );
   }
 
+  @Override
+  public void notifyCheckpointAborted(long checkpointId) {
+    if (checkpointId == this.checkpointId) {
+      executor.execute(() -> {
+        this.ckpMetadata.abortInstant(this.instant);
+      }, "abort instant %s", this.instant);
+    }
+  }
+
   @Override
   public void resetToCheckpoint(long checkpointID, byte[] checkpointData) {
     // no operation
@@ -340,6 +366,7 @@ public class StreamWriteOperatorCoordinator
     // because the instant request from write task is asynchronous.
     this.instant = this.writeClient.startCommit();
     this.metaClient.getActiveTimeline().transitionRequestedToInflight(tableState.commitAction, this.instant);
+    this.ckpMetadata.startInstant(this.instant);
     LOG.info("Create instant [{}] for table [{}] with type [{}]", this.instant,
         this.conf.getString(FlinkOptions.TABLE_NAME), conf.getString(FlinkOptions.TABLE_TYPE));
   }
@@ -488,6 +515,7 @@ public class StreamWriteOperatorCoordinator
           tableState.commitAction, partitionToReplacedFileIds);
       if (success) {
         reset();
+        this.ckpMetadata.commitInstant(instant);
         LOG.info("Commit instant [{}] success!", instant);
       } else {
         throw new HoodieException(String.format("Commit instant [%s] failed!", instant));

hudi-flink/src/main/java/org/apache/hudi/sink/bootstrap/BootstrapOperator.java

@@ -24,7 +24,6 @@ import org.apache.hudi.common.model.HoodieAvroRecord;
 import org.apache.hudi.common.model.HoodieKey;
 import org.apache.hudi.common.model.HoodieRecord;
 import org.apache.hudi.common.model.HoodieRecordGlobalLocation;
-import org.apache.hudi.common.table.HoodieTableMetaClient;
 import org.apache.hudi.common.table.TableSchemaResolver;
 import org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner;
 import org.apache.hudi.common.table.timeline.HoodieInstant;
@@ -37,6 +36,7 @@ import org.apache.hudi.config.HoodieWriteConfig;
 import org.apache.hudi.configuration.FlinkOptions;
 import org.apache.hudi.exception.HoodieException;
 import org.apache.hudi.sink.bootstrap.aggregate.BootstrapAggFunction;
+import org.apache.hudi.sink.meta.CkpMetadata;
 import org.apache.hudi.table.HoodieTable;
 import org.apache.hudi.table.format.FormatUtils;
 import org.apache.hudi.util.FlinkTables;
@@ -83,6 +83,8 @@ public class BootstrapOperator<I, O extends HoodieRecord<?>>
 
   protected HoodieTable<?, ?, ?, ?> hoodieTable;
 
+  private CkpMetadata ckpMetadata;
+
   protected final Configuration conf;
 
   protected transient org.apache.hadoop.conf.Configuration hadoopConf;
@@ -101,8 +103,7 @@ public class BootstrapOperator<I, O extends HoodieRecord<?>>
 
   @Override
   public void snapshotState(StateSnapshotContext context) throws Exception {
-    HoodieTableMetaClient metaClient = StreamerUtil.createMetaClient(this.conf);
+    lastInstantTime = this.ckpMetadata.lastPendingInstant();
-    lastInstantTime = StreamerUtil.getLastPendingInstant(metaClient);
     instantState.update(Collections.singletonList(lastInstantTime));
   }
 
@@ -124,6 +125,7 @@ public class BootstrapOperator<I, O extends HoodieRecord<?>>
     this.hadoopConf = StreamerUtil.getHadoopConf();
     this.writeConfig = StreamerUtil.getHoodieClientConfig(this.conf, true);
     this.hoodieTable = FlinkTables.createTable(writeConfig, hadoopConf, getRuntimeContext());
+    this.ckpMetadata = CkpMetadata.getInstance(hoodieTable.getMetaClient().getFs(), this.writeConfig.getBasePath());
     this.aggregateManager = getRuntimeContext().getGlobalAggregateManager();
 
     preLoadIndexRecords();

hudi-flink/src/main/java/org/apache/hudi/sink/bulk/BulkInsertWriteFunction.java

@@ -21,11 +21,11 @@ package org.apache.hudi.sink.bulk;
 import org.apache.hudi.client.HoodieFlinkWriteClient;
 import org.apache.hudi.client.WriteStatus;
 import org.apache.hudi.common.model.WriteOperationType;
-import org.apache.hudi.common.table.HoodieTableMetaClient;
 import org.apache.hudi.configuration.FlinkOptions;
 import org.apache.hudi.sink.StreamWriteOperatorCoordinator;
 import org.apache.hudi.sink.common.AbstractWriteFunction;
 import org.apache.hudi.sink.event.WriteMetadataEvent;
+import org.apache.hudi.sink.meta.CkpMetadata;
 import org.apache.hudi.sink.utils.TimeWait;
 import org.apache.hudi.util.StreamerUtil;
 
@@ -79,11 +79,6 @@ public class BulkInsertWriteFunction<I>
    */
   private int taskID;
 
-  /**
-   * Meta Client.
-   */
-  private transient HoodieTableMetaClient metaClient;
-
   /**
    * Write Client.
    */
@@ -99,6 +94,11 @@ public class BulkInsertWriteFunction<I>
    */
   private transient OperatorEventGateway eventGateway;
 
+  /**
+   * Checkpoint metadata.
+   */
+  private CkpMetadata ckpMetadata;
+
   /**
    * Constructs a StreamingSinkFunction.
    *
@@ -112,9 +112,9 @@ public class BulkInsertWriteFunction<I>
   @Override
   public void open(Configuration parameters) throws IOException {
     this.taskID = getRuntimeContext().getIndexOfThisSubtask();
-    this.metaClient = StreamerUtil.createMetaClient(this.config);
     this.writeClient = StreamerUtil.createWriteClient(this.config, getRuntimeContext());
-    this.initInstant = StreamerUtil.getLastPendingInstant(this.metaClient, false);
+    this.ckpMetadata = CkpMetadata.getInstance(config.getString(FlinkOptions.PATH));
+    this.initInstant = lastPendingInstant();
     sendBootstrapEvent();
     initWriterHelper();
   }
@@ -187,7 +187,7 @@ public class BulkInsertWriteFunction<I>
    * Returns the last pending instant time.
    */
   protected String lastPendingInstant() {
-    return StreamerUtil.getLastPendingInstant(this.metaClient);
+    return this.ckpMetadata.lastPendingInstant();
   }
 
   private String instantToWrite() {

hudi-flink/src/main/java/org/apache/hudi/sink/common/AbstractStreamWriteFunction.java

@@ -26,6 +26,7 @@ import org.apache.hudi.configuration.FlinkOptions;
 import org.apache.hudi.sink.StreamWriteOperatorCoordinator;
 import org.apache.hudi.sink.event.CommitAckEvent;
 import org.apache.hudi.sink.event.WriteMetadataEvent;
+import org.apache.hudi.sink.meta.CkpMetadata;
 import org.apache.hudi.sink.utils.TimeWait;
 import org.apache.hudi.util.StreamerUtil;
 
@@ -114,6 +115,11 @@ public abstract class AbstractStreamWriteFunction<I>
    */
   protected List<WriteStatus> writeStatuses;
 
+  /**
+   * The checkpoint metadata.
+   */
+  private transient CkpMetadata ckpMetadata;
+
   /**
    * Constructs a StreamWriteFunctionBase.
    *
@@ -135,6 +141,7 @@ public abstract class AbstractStreamWriteFunction<I>
             TypeInformation.of(WriteMetadataEvent.class)
         ));
 
+    this.ckpMetadata = CkpMetadata.getInstance(this.metaClient.getFs(), this.metaClient.getBasePath());
     this.currentInstant = lastPendingInstant();
     if (context.isRestored()) {
       restoreWriteMetadata();
@@ -217,7 +224,7 @@ public abstract class AbstractStreamWriteFunction<I>
    * Returns the last pending instant time.
    */
   protected String lastPendingInstant() {
-    return StreamerUtil.getLastPendingInstant(this.metaClient);
+    return this.ckpMetadata.lastPendingInstant();
   }
 
   /**
@@ -238,7 +245,7 @@ public abstract class AbstractStreamWriteFunction<I>
       // wait condition:
       // 1. there is no inflight instant
       // 2. the inflight instant does not change and the checkpoint has buffering data
-      if (instant == null || (instant.equals(this.currentInstant) && hasData)) {
+      if (instant == null || (instant.equals(this.currentInstant) && hasData && !this.ckpMetadata.isAborted(instant))) {
         // sleep for a while
         timeWait.waitFor();
         // refresh the inflight instant

hudi-flink/src/main/java/org/apache/hudi/sink/meta/CkpMessage.java

@@ -0,0 +1,113 @@
+/*
+ * 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.sink.meta;
+
+import org.apache.hudi.common.util.ValidationUtils;
+
+import org.apache.hadoop.fs.FileStatus;
+import org.jetbrains.annotations.NotNull;
+
+import java.io.Serializable;
+import java.util.Arrays;
+import java.util.Comparator;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * A checkpoint message.
+ */
+public class CkpMessage implements Serializable, Comparable<CkpMessage> {
+  private static final long serialVersionUID = 1L;
+
+  public static final Comparator<CkpMessage> COMPARATOR = Comparator.comparing(CkpMessage::getInstant)
+      .thenComparing(CkpMessage::getState);
+
+  private final String instant; // the instant time
+  private final State state;   // the checkpoint state
+
+  public CkpMessage(String instant, String state) {
+    this.instant = instant;
+    this.state = State.valueOf(state);
+  }
+
+  public CkpMessage(FileStatus fileStatus) {
+    String fileName = fileStatus.getPath().getName();
+    String[] nameAndExt = fileName.split("\\.");
+    ValidationUtils.checkState(nameAndExt.length == 2);
+    String name = nameAndExt[0];
+    String ext = nameAndExt[1];
+
+    this.instant = name;
+    this.state = State.valueOf(ext);
+  }
+
+  public String getInstant() {
+    return instant;
+  }
+
+  public State getState() {
+    return state;
+  }
+
+  public boolean isAborted() {
+    return State.ABORTED == this.state;
+  }
+
+  public boolean isComplete() {
+    return State.COMPLETED == this.state;
+  }
+
+  public boolean isInflight() {
+    return State.INFLIGHT == this.state;
+  }
+
+  public static String getFileName(String instant, State state) {
+    return instant + "." + state.name();
+  }
+
+  public static List<String> getAllFileNames(String instant) {
+    return Arrays.stream(State.values())
+        .map(state -> getFileName(instant, state))
+        .collect(Collectors.toList());
+  }
+
+  @Override
+  public int compareTo(@NotNull CkpMessage o) {
+    return COMPARATOR.compare(this, o);
+  }
+
+  /**
+   * Instant State.
+   */
+  public enum State {
+    // Inflight instant
+    INFLIGHT,
+    // Aborted instant
+    // An instant can be aborted then be reused again, so it has lower priority
+    // than COMPLETED
+    ABORTED,
+    // Committed instant
+    COMPLETED
+  }
+
+  @Override
+  public String toString() {
+    return "Ckp{" + "instant='" + instant + '\'' + ", state='" + state + '\'' + '}';
+  }
+}

hudi-flink/src/main/java/org/apache/hudi/sink/meta/CkpMetadata.java

@@ -0,0 +1,226 @@
+/*
+ * 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.sink.meta;
+
+import org.apache.hudi.common.fs.FSUtils;
+import org.apache.hudi.common.table.HoodieTableMetaClient;
+import org.apache.hudi.common.util.ValidationUtils;
+import org.apache.hudi.exception.HoodieException;
+import org.apache.hudi.util.StreamerUtil;
+
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import javax.annotation.Nullable;
+
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+import java.util.stream.Collectors;
+
+/**
+ * The checkpoint metadata for bookkeeping the checkpoint messages.
+ *
+ * <p>Each time the driver starts a new instant, it writes a commit message into the metadata, the write tasks
+ * then consume the message and unblock the data flushing.
+ *
+ * <p>Why we use the DFS based message queue instead of sending
+ * the {@link org.apache.flink.runtime.operators.coordination.OperatorEvent} ?
+ * The write task handles the operator event using the main mailbox executor which has the lowest priority for mails,
+ * it is also used to process the inputs. When the write task blocks and waits for the operator event to ack the valid instant to write,
+ * it actually blocks all the subsequent events in the mailbox, the operator event would never be consumed then it causes deadlock.
+ *
+ * <p>The checkpoint metadata is also more lightweight than the active timeline.
+ *
+ * <p>NOTE: should be removed in the future if we have good manner to handle the async notifications from driver.
+ */
+public class CkpMetadata implements Serializable {
+  private static final long serialVersionUID = 1L;
+
+  private static final Logger LOG = LoggerFactory.getLogger(CkpMetadata.class);
+
+  protected static final int MAX_RETAIN_CKP_NUM = 3;
+
+  // the ckp metadata directory
+  private static final String CKP_META = "ckp_meta";
+
+  private final FileSystem fs;
+  protected final Path path;
+
+  private List<CkpMessage> messages;
+  private List<String> instantCache;
+
+  private CkpMetadata(String basePath) {
+    this(FSUtils.getFs(basePath, StreamerUtil.getHadoopConf()), basePath);
+  }
+
+  private CkpMetadata(FileSystem fs, String basePath) {
+    this.fs = fs;
+    this.path = new Path(ckpMetaPath(basePath));
+  }
+
+  public void close() {
+    this.instantCache = null;
+  }
+
+  // -------------------------------------------------------------------------
+  //  WRITE METHODS
+  // -------------------------------------------------------------------------
+  /**
+   * Initialize the message bus, would clean all the messages and publish the last pending instant.
+   *
+   * <p>This expects to be called by the driver.
+   */
+  public void bootstrap(HoodieTableMetaClient metaClient) throws IOException {
+    fs.delete(path, true);
+    fs.mkdirs(path);
+    metaClient.getActiveTimeline().getCommitsTimeline().filterPendingExcludingCompaction()
+        .lastInstant().ifPresent(instant -> startInstant(instant.getTimestamp()));
+  }
+
+  public void startInstant(String instant) {
+    Path path = fullPath(CkpMessage.getFileName(instant, CkpMessage.State.INFLIGHT));
+    try {
+      fs.createNewFile(path);
+    } catch (IOException e) {
+      throw new HoodieException("Exception while adding checkpoint start metadata for instant: " + instant);
+    }
+    // cleaning
+    clean(instant);
+  }
+
+  private void clean(String newInstant) {
+    if (this.instantCache == null) {
+      this.instantCache = new ArrayList<>();
+    }
+    this.instantCache.add(newInstant);
+    if (instantCache.size() > MAX_RETAIN_CKP_NUM) {
+      final String instant = instantCache.get(0);
+      boolean[] error = new boolean[1];
+      CkpMessage.getAllFileNames(instant).stream().map(this::fullPath).forEach(path -> {
+        try {
+          fs.delete(path, false);
+        } catch (IOException e) {
+          error[0] = true;
+          LOG.warn("Exception while cleaning the checkpoint meta file: " + path);
+        }
+      });
+      if (!error[0]) {
+        instantCache.remove(0);
+      }
+    }
+  }
+
+  /**
+   * Add a checkpoint commit message.
+   *
+   * @param instant   The committed instant
+   */
+  public void commitInstant(String instant) {
+    Path path = fullPath(CkpMessage.getFileName(instant, CkpMessage.State.COMPLETED));
+    try {
+      fs.createNewFile(path);
+    } catch (IOException e) {
+      throw new HoodieException("Exception while adding checkpoint commit metadata for instant: " + instant);
+    }
+  }
+
+  /**
+   * Add an aborted checkpoint message.
+   */
+  public void abortInstant(String instant) {
+    Path path = fullPath(CkpMessage.getFileName(instant, CkpMessage.State.ABORTED));
+    try {
+      fs.createNewFile(path);
+    } catch (IOException e) {
+      throw new HoodieException("Exception while adding checkpoint abort metadata for instant: " + instant);
+    }
+  }
+
+  // -------------------------------------------------------------------------
+  //  READ METHODS
+  // -------------------------------------------------------------------------
+
+  private void load() {
+    try {
+      this.messages = scanCkpMetadata(this.path);
+    } catch (IOException e) {
+      throw new HoodieException("Exception while scanning the checkpoint meta files under path: " + this.path);
+    }
+  }
+
+  @Nullable
+  public String lastPendingInstant() {
+    load();
+    for (int i = this.messages.size() - 1; i >= 0; i--) {
+      CkpMessage ckpMsg = this.messages.get(i);
+      // consider 'aborted' as pending too to reuse the instant
+      if (!ckpMsg.isComplete()) {
+        return ckpMsg.getInstant();
+      }
+    }
+    return null;
+  }
+
+  public List<CkpMessage> getMessages() {
+    load();
+    return messages;
+  }
+
+  public boolean isAborted(String instant) {
+    ValidationUtils.checkState(this.messages != null, "The checkpoint metadata should #load first");
+    return this.messages.stream().anyMatch(ckpMsg -> instant.equals(ckpMsg.getInstant()) && ckpMsg.isAborted());
+  }
+
+  // -------------------------------------------------------------------------
+  //  Utilities
+  // -------------------------------------------------------------------------
+  public static CkpMetadata getInstance(String basePath) {
+    return new CkpMetadata(basePath);
+  }
+
+  public static CkpMetadata getInstance(FileSystem fs, String basePath) {
+    return new CkpMetadata(fs, basePath);
+  }
+
+  protected static String ckpMetaPath(String basePath) {
+    return basePath + Path.SEPARATOR + HoodieTableMetaClient.AUXILIARYFOLDER_NAME + Path.SEPARATOR + CKP_META;
+  }
+
+  private Path fullPath(String fileName) {
+    return new Path(path, fileName);
+  }
+
+  private List<CkpMessage> scanCkpMetadata(Path ckpMetaPath) throws IOException {
+    return Arrays.stream(this.fs.listStatus(ckpMetaPath)).map(CkpMessage::new)
+        .collect(Collectors.groupingBy(CkpMessage::getInstant)).values().stream()
+        .map(messages -> messages.stream().reduce((x, y) -> {
+          // Pick the one with the highest state
+          if (x.getState().compareTo(y.getState()) >= 0) {
+            return x;
+          }
+          return y;
+        }).get())
+        .sorted().collect(Collectors.toList());
+  }
+}

hudi-flink/src/main/java/org/apache/hudi/util/StreamerUtil.java

@@ -488,7 +488,7 @@ public class StreamerUtil {
     if (reloadTimeline) {
       metaClient.reloadActiveTimeline();
     }
-    return metaClient.getCommitsTimeline().filterInflights()
+    return metaClient.getCommitsTimeline().filterPendingExcludingCompaction()
         .lastInstant()
         .map(HoodieInstant::getTimestamp)
         .orElse(null);

hudi-flink/src/test/java/org/apache/hudi/sink/TestWriteCopyOnWrite.java

@@ -95,8 +95,8 @@ public class TestWriteCopyOnWrite extends TestWriteBase {
         .assertEmptyEvent()
         .checkpointFails(1)
         .consume(TestData.DATA_SET_INSERT)
-        .checkpointThrows(2,
+        //.checkpointThrows(2,
-            "Timeout(1000ms) while waiting for instant initialize")
+        //    "Timeout(1000ms) while waiting for instant initialize")
         // do not send the write event and fails the checkpoint,
         // behaves like the last checkpoint is successful.
         .checkpointFails(2)

hudi-flink/src/test/java/org/apache/hudi/sink/compact/ITTestHoodieFlinkCompactor.java

@@ -178,10 +178,11 @@ public class ITTestHoodieFlinkCompactor {
     options.put(FlinkOptions.CHANGELOG_ENABLED.key(), enableChangelog + "");
     String hoodieTableDDL = TestConfigurations.getCreateHoodieTableDDL("t1", options);
     tableEnv.executeSql(hoodieTableDDL);
-    tableEnv.executeSql(TestSQL.INSERT_T1).await();
 
-    // wait for the asynchronous commit to finish
+    // insert dataset
-    TimeUnit.SECONDS.sleep(5);
+    tableEnv.executeSql(TestSQL.INSERT_T1).await();
+    // update the dataset
+    tableEnv.executeSql(TestSQL.UPDATE_INSERT_T1).await();
 
     // Make configuration and setAvroSchema.
     StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
@@ -195,8 +196,6 @@ public class ITTestHoodieFlinkCompactor {
     HoodieFlinkCompactor.AsyncCompactionService asyncCompactionService = new HoodieFlinkCompactor.AsyncCompactionService(cfg, conf, env);
     asyncCompactionService.start(null);
 
-    tableEnv.executeSql(TestSQL.UPDATE_INSERT_T1).await();
-
     // wait for the asynchronous commit to finish
     TimeUnit.SECONDS.sleep(5);
 

hudi-flink/src/test/java/org/apache/hudi/sink/meta/TestCkpMetadata.java

@@ -0,0 +1,75 @@
+/*
+ * 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.sink.meta;
+
+import org.apache.hudi.common.fs.FSUtils;
+import org.apache.hudi.util.StreamerUtil;
+import org.apache.hudi.utils.TestConfigurations;
+
+import org.apache.flink.configuration.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+import java.io.File;
+import java.util.stream.IntStream;
+
+import static org.hamcrest.CoreMatchers.is;
+import static org.hamcrest.MatcherAssert.assertThat;
+
+/**
+ * Test cases for {@link CkpMetadata}.
+ */
+public class TestCkpMetadata {
+
+  private CkpMetadata metadata;
+
+  @TempDir
+  File tempFile;
+
+  @BeforeEach
+  public void beforeEach() throws Exception {
+    String basePath = tempFile.getAbsolutePath();
+    FileSystem fs = FSUtils.getFs(tempFile.getAbsolutePath(), StreamerUtil.getHadoopConf());
+
+    Configuration conf = TestConfigurations.getDefaultConf(basePath);
+    StreamerUtil.initTableIfNotExists(conf);
+
+    this.metadata = CkpMetadata.getInstance(fs, basePath);
+  }
+
+  @Test
+  void testWriteAndReadMessage() {
+    // write and read 5 committed checkpoints
+    IntStream.range(0, 3).forEach(i -> metadata.startInstant(i + ""));
+
+    assertThat(metadata.lastPendingInstant(), is("2"));
+    metadata.commitInstant("2");
+    assertThat(metadata.lastPendingInstant(), is("1"));
+
+    // test cleaning
+    IntStream.range(3, 6).forEach(i -> metadata.startInstant(i + ""));
+    assertThat(metadata.getMessages().size(), is(3));
+    // commit and abort instant does not trigger cleaning
+    metadata.commitInstant("6");
+    metadata.abortInstant("7");
+    assertThat(metadata.getMessages().size(), is(5));
+  }
+}