[GitHub] [hudi] LinMingQiang commented on a change in pull request #4724: [HUDI-2815] add partial overwrite payload to support partial overwrit…

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LinMingQiang commented on a change in pull request #4724:
URL: https://github.com/apache/hudi/pull/4724#discussion_r814557644



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File path: hudi-common/src/main/java/org/apache/hudi/common/model/PartialOverwriteWithLatestAvroPayload.java
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@@ -0,0 +1,137 @@
+/*
+ * 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.model;
+
+import org.apache.hudi.common.util.Option;
+
+import org.apache.avro.Schema;
+import org.apache.avro.generic.GenericRecord;
+import org.apache.avro.generic.IndexedRecord;
+
+import java.io.IOException;
+import java.util.List;
+import java.util.Objects;
+import java.util.Properties;
+
+import static org.apache.hudi.avro.HoodieAvroUtils.bytesToAvro;
+
+/**
+ * The only difference with {@link OverwriteNonDefaultsWithLatestAvroPayload} is that it supports
+ * merging the latest non-null partial fields with the old record instead of replacing the whole record.
+ * And merging the non-null fields during preCombine multiple records with same record key instead of choosing the latest record based on ordering field.
+ *
+ * <p> Regarding #combineAndGetUpdateValue, Assuming a {@link GenericRecord} has row schema: (f0 int , f1 int, f2 int).
+ * The first record value is: (1, 2, 3), the second record value is: (4, 5, null) with the field f2 value as null.
+ * Calling the #combineAndGetUpdateValue method of the two records returns record: (4, 5, 3).
+ * Note that field f2 value is ignored because it is null. </p>
+ *
+ * <p> Regarding #preCombine, Assuming a {@link GenericRecord} has row schema: (f0 int , f1 int, f2 int, o1 int),
+ * and initial two {@link PartialOverwriteWithLatestAvroPayload} with different ordering value.
+ * The first record value is (1, null, 1, 1) with the filed f1 value as null, the second value is: (2, 2, null, 2) with the f2 value as null.
+ * Calling the #preCombine method of the two records returns record: (2, 2, 1, 2).
+ * Note:
+ * <ol>
+ *   <li>the field f0 value is 2 because the ordering value of second record is bigger.</li>
+ *   <li>the filed f1 value is 2 because the f2 value of first record is null.</li>
+ *   <li>the filed f2 value is 1 because the f2 value of second record is null.</li>
+ *   <li>the filed o1 value is 2 because the ordering value of second record is bigger.</li>
+ * </ol>
+ *
+ * </p>
+ */
+public class PartialOverwriteWithLatestAvroPayload extends OverwriteWithLatestAvroPayload {
+
+  public PartialOverwriteWithLatestAvroPayload(GenericRecord record, Comparable orderingVal) {
+    super(record, orderingVal);
+  }
+
+  public PartialOverwriteWithLatestAvroPayload(Option<GenericRecord> record) {
+    super(record); // natural order
+  }
+
+  @Override
+  public Option<IndexedRecord> combineAndGetUpdateValue(IndexedRecord currentValue, Schema schema) throws IOException {
+    if (recordBytes.length == 0) {
+      return Option.empty();
+    }
+
+    GenericRecord incomingRecord = bytesToAvro(recordBytes, schema);
+    if (isDeleteRecord(incomingRecord)) {
+      return Option.empty();
+    }
+
+    GenericRecord currentRecord = (GenericRecord) currentValue;
+    List<Schema.Field> fields = schema.getFields();
+    fields.forEach(field -> {
+      Object value = incomingRecord.get(field.name());
+      if (Objects.nonNull(value)) {
+        currentRecord.put(field.name(), value);
+      }
+    });
+
+    return Option.of(currentRecord);
+  }
+
+  @Override
+  public int compareTo(OverwriteWithLatestAvroPayload oldValue) {
+    return orderingVal.compareTo(oldValue.orderingVal);
+  }
+
+  @Override
+  public OverwriteWithLatestAvroPayload preCombine(OverwriteWithLatestAvroPayload oldValue, Properties properties, Schema schema) {
+    if (null == schema) {
+      return super.preCombine(oldValue);
+    }
+
+    try {
+      Option<IndexedRecord> incomingOption = getInsertValue(schema);
+      Option<IndexedRecord> oldRecordOption = oldValue.getInsertValue(schema);
+
+      if (incomingOption.isPresent() && oldRecordOption.isPresent()) {
+        GenericRecord incomingRecord = (GenericRecord) incomingOption.get();
+        GenericRecord oldRecord = (GenericRecord) oldRecordOption.get();
+        boolean chooseIncomingRecord = this.orderingVal.compareTo(oldValue.orderingVal) > 0;

Review comment:
       This place needs to be changed to >= , because when we do not set the preCombine field, the first data will always be used instead of the latest




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