From 30a930626242bd0d887ae1c43afc0cc90b6e8608 Mon Sep 17 00:00:00 2001 From: Bhanu Chander Vallabaneni Date: Tue, 11 Aug 2026 22:32:30 -0400 Subject: [PATCH] [common] Fix equals/hashCode contract in value and kv record batches DefaultValueRecordBatch and DefaultKvRecordBatch override equals() with value semantics but do not override hashCode(). Both extend Object and neither equals() delegates to super.equals(), so hashCode() is the identity hash: two byte-identical batches are equal but hash differently, violating the general contract of Object.hashCode(). The third batch implementation in the same package, DefaultLogRecordBatch, has the identical equals() shape and already hashes the same byte range. Mirror it in both classes so the three siblings stay consistent. This is not a fix for the flakiness in #3877; it only removes the contract violation observed while diagnosing it. --- .../fluss/record/DefaultKvRecordBatch.java | 6 ++ .../fluss/record/DefaultValueRecordBatch.java | 6 ++ .../record/DefaultKvRecordBatchTest.java | 37 ++++++++++ .../record/DefaultValueRecordBatchTest.java | 69 +++++++++++++++++++ 4 files changed, 118 insertions(+) create mode 100644 fluss-common/src/test/java/org/apache/fluss/record/DefaultValueRecordBatchTest.java diff --git a/fluss-common/src/main/java/org/apache/fluss/record/DefaultKvRecordBatch.java b/fluss-common/src/main/java/org/apache/fluss/record/DefaultKvRecordBatch.java index 1fe83650d19..852c7ebbf25 100644 --- a/fluss-common/src/main/java/org/apache/fluss/record/DefaultKvRecordBatch.java +++ b/fluss-common/src/main/java/org/apache/fluss/record/DefaultKvRecordBatch.java @@ -23,6 +23,7 @@ import org.apache.fluss.memory.MemorySegment; import org.apache.fluss.record.bytesview.BytesView; import org.apache.fluss.utils.CloseableIterator; +import org.apache.fluss.utils.MurmurHashUtils; import org.apache.fluss.utils.crc.Crc32C; import java.nio.ByteBuffer; @@ -219,6 +220,11 @@ public boolean equals(Object o) { && segment.equalTo(that.segment, position, that.position, sizeInBytes); } + @Override + public int hashCode() { + return MurmurHashUtils.hashBytes(segment, position, sizeInBytes()); + } + abstract class KvRecordIterator implements CloseableIterator { private final int numRecords; private int readRecords = 0; diff --git a/fluss-common/src/main/java/org/apache/fluss/record/DefaultValueRecordBatch.java b/fluss-common/src/main/java/org/apache/fluss/record/DefaultValueRecordBatch.java index 3bb7539f615..55877215481 100644 --- a/fluss-common/src/main/java/org/apache/fluss/record/DefaultValueRecordBatch.java +++ b/fluss-common/src/main/java/org/apache/fluss/record/DefaultValueRecordBatch.java @@ -21,6 +21,7 @@ import org.apache.fluss.memory.MemorySegmentOutputView; import org.apache.fluss.row.BinaryRow; import org.apache.fluss.utils.CloseableIterator; +import org.apache.fluss.utils.MurmurHashUtils; import java.io.IOException; import java.nio.ByteBuffer; @@ -132,6 +133,11 @@ public boolean equals(Object o) { && segment.equalTo(that.segment, position, that.position, sizeInBytes); } + @Override + public int hashCode() { + return MurmurHashUtils.hashBytes(segment, position, sizeInBytes()); + } + // ------------------------------------------------------------------------------------------ abstract class ValueRecordIterator implements CloseableIterator { diff --git a/fluss-common/src/test/java/org/apache/fluss/record/DefaultKvRecordBatchTest.java b/fluss-common/src/test/java/org/apache/fluss/record/DefaultKvRecordBatchTest.java index 6c8b483a0bf..cbdceced5f0 100644 --- a/fluss-common/src/test/java/org/apache/fluss/record/DefaultKvRecordBatchTest.java +++ b/fluss-common/src/test/java/org/apache/fluss/record/DefaultKvRecordBatchTest.java @@ -27,7 +27,9 @@ import java.util.ArrayList; import java.util.List; +import static org.apache.fluss.record.TestData.DATA1_ROW_TYPE; import static org.apache.fluss.record.TestData.DATA1_SCHEMA; +import static org.apache.fluss.testutils.DataTestUtils.compactedRow; import static org.assertj.core.api.Assertions.assertThat; /** Test for {@link DefaultKvRecordBatch}. */ @@ -76,4 +78,39 @@ KvFormat.COMPACTED, new TestingSchemaGetter(1, DATA1_SCHEMA)))) { builder.close(); } + + @Test + void testEqualsAndHashCode() throws Exception { + DefaultKvRecordBatch batch1 = buildBatch(); + DefaultKvRecordBatch batch2 = buildBatch(); + + assertThat(batch1).isEqualTo(batch2); + assertThat(batch1).hasSameHashCodeAs(batch2); + } + + @Test + void testHashCodeDiffersForDifferentContents() throws Exception { + DefaultKvRecordBatch batch1 = buildBatch(); + DefaultKvRecordBatch batch2 = buildBatch(new byte[] {(byte) 9, (byte) 9}); + + assertThat(batch1).isNotEqualTo(batch2); + assertThat(batch1.hashCode()).isNotEqualTo(batch2.hashCode()); + } + + private DefaultKvRecordBatch buildBatch() throws Exception { + return buildBatch(new byte[] {(byte) 1, (byte) 1}); + } + + private DefaultKvRecordBatch buildBatch(byte[] key) throws Exception { + KvRecordBatchBuilder builder = + KvRecordBatchBuilder.builder( + schemaId, + Integer.MAX_VALUE, + new UnmanagedPagedOutputView(100), + KvFormat.COMPACTED); + builder.append(key, compactedRow(DATA1_ROW_TYPE, new Object[] {1, "a1"})); + DefaultKvRecordBatch batch = DefaultKvRecordBatch.pointToBytesView(builder.build()); + builder.close(); + return batch; + } } diff --git a/fluss-common/src/test/java/org/apache/fluss/record/DefaultValueRecordBatchTest.java b/fluss-common/src/test/java/org/apache/fluss/record/DefaultValueRecordBatchTest.java new file mode 100644 index 00000000000..5558ec7c04a --- /dev/null +++ b/fluss-common/src/test/java/org/apache/fluss/record/DefaultValueRecordBatchTest.java @@ -0,0 +1,69 @@ +/* + * 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.fluss.record; + +import org.junit.jupiter.api.Test; + +import static org.apache.fluss.record.TestData.DATA1_ROW_TYPE; +import static org.apache.fluss.record.TestData.DEFAULT_SCHEMA_ID; +import static org.apache.fluss.testutils.DataTestUtils.compactedRow; +import static org.assertj.core.api.Assertions.assertThat; + +/** Test for {@link DefaultValueRecordBatch}. */ +class DefaultValueRecordBatchTest { + + @Test + void testEqualsAndHashCode() throws Exception { + DefaultValueRecordBatch batch1 = buildBatch(); + DefaultValueRecordBatch batch2 = buildBatch(); + + assertThat(batch1).isEqualTo(batch2); + assertThat(batch1).hasSameHashCodeAs(batch2); + } + + @Test + void testHashCodeDiffersForDifferentContents() throws Exception { + DefaultValueRecordBatch.Builder builder = DefaultValueRecordBatch.builder(); + builder.append(DEFAULT_SCHEMA_ID, compactedRow(DATA1_ROW_TYPE, new Object[] {1, "a1"})); + DefaultValueRecordBatch batch1 = builder.build(); + + DefaultValueRecordBatch.Builder otherBuilder = DefaultValueRecordBatch.builder(); + otherBuilder.append( + DEFAULT_SCHEMA_ID, compactedRow(DATA1_ROW_TYPE, new Object[] {2, "a2"})); + DefaultValueRecordBatch batch2 = otherBuilder.build(); + + assertThat(batch1).isNotEqualTo(batch2); + assertThat(batch1.hashCode()).isNotEqualTo(batch2.hashCode()); + } + + @Test + void testEmptyBatchesAreEqualAndShareHashCode() throws Exception { + DefaultValueRecordBatch batch1 = DefaultValueRecordBatch.builder().build(); + DefaultValueRecordBatch batch2 = DefaultValueRecordBatch.builder().build(); + + assertThat(batch1).isEqualTo(batch2); + assertThat(batch1).hasSameHashCodeAs(batch2); + } + + private static DefaultValueRecordBatch buildBatch() throws Exception { + DefaultValueRecordBatch.Builder builder = DefaultValueRecordBatch.builder(); + builder.append(DEFAULT_SCHEMA_ID, compactedRow(DATA1_ROW_TYPE, new Object[] {1, "a1"})); + builder.append(DEFAULT_SCHEMA_ID, compactedRow(DATA1_ROW_TYPE, new Object[] {2, "a2"})); + return builder.build(); + } +}