[HUDI-2117] Unpersist the input rdd after the commit is completed to … (#3207)

Co-authored-by: Vinoth Chandar <vinoth@apache.org>

hudi-client/hudi-client-common/src/main/java/org/apache/hudi/client/AbstractHoodieWriteClient.java

@@ -18,9 +18,6 @@
 
 package org.apache.hudi.client;
 
-import com.codahale.metrics.Timer;
-import java.util.stream.Stream;
-import org.apache.hadoop.conf.Configuration;
 import org.apache.hudi.avro.model.HoodieCleanMetadata;
 import org.apache.hudi.avro.model.HoodieCleanerPlan;
 import org.apache.hudi.avro.model.HoodieClusteringPlan;
@@ -70,6 +67,9 @@ import org.apache.hudi.table.HoodieTimelineArchiveLog;
 import org.apache.hudi.table.MarkerFiles;
 import org.apache.hudi.table.action.HoodieWriteMetadata;
 import org.apache.hudi.table.action.savepoint.SavepointHelpers;
+
+import com.codahale.metrics.Timer;
+import org.apache.hadoop.conf.Configuration;
 import org.apache.log4j.LogManager;
 import org.apache.log4j.Logger;
 
@@ -81,6 +81,7 @@ import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
 /**
  * Abstract Write Client providing functionality for performing commit, index updates and rollback
@@ -189,6 +190,7 @@ public abstract class AbstractHoodieWriteClient<T extends HoodieRecordPayload, I
       commit(table, commitActionType, instantTime, metadata, stats);
       postCommit(table, metadata, instantTime, extraMetadata);
       LOG.info("Committed " + instantTime);
+      releaseResources();
     } catch (IOException e) {
       throw new HoodieCommitException("Failed to complete commit " + config.getBasePath() + " at time " + instantTime, e);
     } finally {
@@ -1041,6 +1043,13 @@ public abstract class AbstractHoodieWriteClient<T extends HoodieRecordPayload, I
     }
   }
 
+  /**
+   * Called after each write, to release any resources used.
+   */
+  protected void releaseResources() {
+    // do nothing here
+  }
+
   @Override
   public void close() {
     // release AsyncCleanerService