diff --git a/hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieArchivedTimeline.java b/hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieArchivedTimeline.java
index ddfe22ac9..a966fee1d 100644
--- a/hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieArchivedTimeline.java
+++ b/hudi-common/src/main/java/org/apache/hudi/common/table/timeline/HoodieArchivedTimeline.java
@@ -27,6 +27,7 @@ import org.apache.hudi.common.model.HoodiePartitionMetadata;
 import org.apache.hudi.common.table.HoodieTableMetaClient;
 import org.apache.hudi.common.table.log.HoodieLogFormat;
 import org.apache.hudi.common.table.log.block.HoodieAvroDataBlock;
+import org.apache.hudi.common.table.log.block.HoodieLogBlock;
 import org.apache.hudi.common.util.ClosableIterator;
 import org.apache.hudi.common.util.CollectionUtils;
 import org.apache.hudi.common.util.FileIOUtils;
@@ -248,16 +249,19 @@ public class HoodieArchivedTimeline extends HoodieDefaultTimeline {
           int instantsInPreviousFile = instantsInRange.size();
           // Read the avro blocks
           while (reader.hasNext()) {
-            HoodieAvroDataBlock blk = (HoodieAvroDataBlock) reader.next();
-            // TODO If we can store additional metadata in datablock, we can skip parsing records
-            // (such as startTime, endTime of records in the block)
-            try (ClosableIterator<IndexedRecord> itr = blk.getRecordItr()) {
-              StreamSupport.stream(Spliterators.spliteratorUnknownSize(itr, Spliterator.IMMUTABLE), true)
-                  // Filter blocks in desired time window
-                  .filter(r -> commitsFilter.apply((GenericRecord) r))
-                  .map(r -> readCommit((GenericRecord) r, loadInstantDetails))
-                  .filter(c -> filter == null || filter.isInRange(c))
-                  .forEach(instantsInRange::add);
+            HoodieLogBlock block = reader.next();
+            if (block instanceof HoodieAvroDataBlock) {
+              HoodieAvroDataBlock avroBlock = (HoodieAvroDataBlock) block;
+              // TODO If we can store additional metadata in datablock, we can skip parsing records
+              // (such as startTime, endTime of records in the block)
+              try (ClosableIterator<IndexedRecord> itr = avroBlock.getRecordItr()) {
+                StreamSupport.stream(Spliterators.spliteratorUnknownSize(itr, Spliterator.IMMUTABLE), true)
+                    // Filter blocks in desired time window
+                    .filter(r -> commitsFilter.apply((GenericRecord) r))
+                    .map(r -> readCommit((GenericRecord) r, loadInstantDetails))
+                    .filter(c -> filter == null || filter.isInRange(c))
+                    .forEach(instantsInRange::add);
+              }
             }
           }
 
diff --git a/hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteOperatorCoordinator.java b/hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteOperatorCoordinator.java
index c4f2e771c..b5ec08a58 100644
--- a/hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteOperatorCoordinator.java
+++ b/hudi-flink-datasource/hudi-flink/src/main/java/org/apache/hudi/sink/StreamWriteOperatorCoordinator.java
@@ -30,7 +30,6 @@ import org.apache.hudi.common.util.ValidationUtils;
 import org.apache.hudi.configuration.FlinkOptions;
 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;
@@ -43,7 +42,6 @@ import org.apache.flink.configuration.Configuration;
 import org.apache.flink.runtime.jobgraph.OperatorID;
 import org.apache.flink.runtime.operators.coordination.OperatorCoordinator;
 import org.apache.flink.runtime.operators.coordination.OperatorEvent;
-import org.apache.flink.runtime.operators.coordination.TaskNotRunningException;
 import org.jetbrains.annotations.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -431,31 +429,6 @@ public class StreamWriteOperatorCoordinator
     addEventToBuffer(event);
   }
 
-  /**
-   * The coordinator reuses the instant if there is no data for this round of checkpoint,
-   * sends the commit ack events to unblock the flushing.
-   */
-  private void sendCommitAckEvents(long checkpointId) {
-    CompletableFuture<?>[] futures = Arrays.stream(this.gateways).filter(Objects::nonNull)
-        .map(gw -> gw.sendEvent(CommitAckEvent.getInstance(checkpointId)))
-        .toArray(CompletableFuture<?>[]::new);
-    CompletableFuture.allOf(futures).whenComplete((resp, error) -> {
-      if (!sendToFinishedTasks(error)) {
-        throw new HoodieException("Error while waiting for the commit ack events to finish sending", error);
-      }
-    });
-  }
-
-  /**
-   * Decides whether the given exception is caused by sending events to FINISHED tasks.
-   *
-   * <p>Ugly impl: the exception may change in the future.
-   */
-  private static boolean sendToFinishedTasks(Throwable throwable) {
-    return throwable.getCause() instanceof TaskNotRunningException
-        || throwable.getCause().getMessage().contains("running");
-  }
-
   /**
    * Commits the instant.
    */
@@ -483,8 +456,6 @@ public class StreamWriteOperatorCoordinator
     if (writeResults.size() == 0) {
       // No data has written, reset the buffer and returns early
       reset();
-      // Send commit ack event to the write function to unblock the flushing
-      sendCommitAckEvents(checkpointId);
       return false;
     }
     doCommit(instant, writeResults);