[HUDI-2901] Fixed the bug clustering jobs cannot running in parallel (#4178)

hudi-client/hudi-spark-client/src/main/java/org/apache/hudi/client/clustering/run/strategy/MultipleSparkJobExecutionStrategy.java

@@ -35,6 +35,7 @@ import org.apache.hudi.common.model.HoodieRecordPayload;
 import org.apache.hudi.common.model.RewriteAvroPayload;
 import org.apache.hudi.common.table.HoodieTableConfig;
 import org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner;
+import org.apache.hudi.common.util.FutureUtils;
 import org.apache.hudi.common.util.Option;
 import org.apache.hudi.common.util.StringUtils;
 import org.apache.hudi.common.util.collection.Pair;
@@ -88,16 +89,17 @@ public abstract class MultipleSparkJobExecutionStrategy<T extends HoodieRecordPa
 
   @Override
   public HoodieWriteMetadata<JavaRDD<WriteStatus>> performClustering(final HoodieClusteringPlan clusteringPlan, final Schema schema, final String instantTime) {
-    // execute clustering for each group async and collect WriteStatus
     JavaSparkContext engineContext = HoodieSparkEngineContext.getSparkContext(getEngineContext());
     // execute clustering for each group async and collect WriteStatus
-    Stream<JavaRDD<WriteStatus>> writeStatusRDDStream = clusteringPlan.getInputGroups().stream()
+    Stream<JavaRDD<WriteStatus>> writeStatusRDDStream = FutureUtils.allOf(
+        clusteringPlan.getInputGroups().stream()
         .map(inputGroup -> runClusteringForGroupAsync(inputGroup,
             clusteringPlan.getStrategy().getStrategyParams(),
             Option.ofNullable(clusteringPlan.getPreserveHoodieMetadata()).orElse(false),
             instantTime))
-        .map(CompletableFuture::join);
-
+            .collect(Collectors.toList()))
+        .join()
+        .stream();
     JavaRDD<WriteStatus>[] writeStatuses = convertStreamToArray(writeStatusRDDStream);
     JavaRDD<WriteStatus> writeStatusRDD = engineContext.union(writeStatuses);
 
@@ -145,7 +147,6 @@ public abstract class MultipleSparkJobExecutionStrategy<T extends HoodieRecordPa
     }
   }
 
-
   /**
    * Submit job to execute clustering for the group.
    */

hudi-common/src/main/java/org/apache/hudi/common/util/FutureUtils.java

@@ -0,0 +1,46 @@
+/*
+ * 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.common.util;
+
+import javax.annotation.Nonnull;
+import java.util.List;
+import java.util.concurrent.CompletableFuture;
+import java.util.stream.Collectors;
+
+/**
+ * A utility class for future operation.
+ */
+public class FutureUtils {
+
+  /**
+   * Parallel CompletableFutures
+   *
+   * @param futures CompletableFuture list
+   * @return a new CompletableFuture which will completed when all of the given CompletableFutures complete.
+   */
+  public static <T> CompletableFuture<List<T>> allOf(@Nonnull List<CompletableFuture<T>> futures) {
+    return CompletableFuture.allOf(futures.toArray(new CompletableFuture[0]))
+        .thenApply(aVoid ->
+            futures.stream()
+                // NOTE: This join wouldn't block, since all the
+                //       futures are completed at this point.
+                .map(CompletableFuture::join)
+                .collect(Collectors.toList()));
+  }
+}