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[Bugfix][JDBC、CDC] Fix Spliter Error in Case of Extensive Duplicate Data #6026

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Jan 18, 2024
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[Bugfix][JDBC、CDC] Fix Spliter Error in Case of Extensive Duplicate Data #6026

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26 changes: 18 additions & 8 deletions ...unnel/connectors/cdc/base/source/enumerator/splitter/AbstractJdbcSourceChunkSplitter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -247,22 +247,32 @@ protected List<ChunkRange> efficientShardingThroughSampling(

double approxSamplePerShard = (double) sampleData.length / shardCount;

Object lastEnd = null;
if (approxSamplePerShard <= 1) {

splits.add(ChunkRange.of(null, sampleData[0]));
for (int i = 0; i < sampleData.length - 1; i++) {
splits.add(ChunkRange.of(sampleData[i], sampleData[i + 1]));
lastEnd = sampleData[0];
for (int i = 1; i < sampleData.length; i++) {
// avoid split duplicate data
if (!sampleData[i].equals(lastEnd)) {
splits.add(ChunkRange.of(lastEnd, sampleData[i]));
lastEnd = sampleData[i];
}
}
splits.add(ChunkRange.of(sampleData[sampleData.length - 1], null));

splits.add(ChunkRange.of(lastEnd, null));

} else {
// Calculate the shard boundaries
for (int i = 0; i < shardCount; i++) {
Object chunkStart = i == 0 ? null : sampleData[(int) (i * approxSamplePerShard)];
Object chunkStart = lastEnd;
Object chunkEnd =
i < shardCount - 1
(i < shardCount - 1)
? sampleData[(int) ((i + 1) * approxSamplePerShard)]
: null;
splits.add(ChunkRange.of(chunkStart, chunkEnd));
// avoid split duplicate data
if (i == 0 || i == shardCount - 1 || !Objects.equals(chunkEnd, chunkStart)) {
splits.add(ChunkRange.of(chunkStart, chunkEnd));
lastEnd = chunkEnd;
}
}
}
return splits;
Expand Down
232 changes: 232 additions & 0 deletions ...l/connectors/cdc/base/source/enumerator/splitter/AbstractJdbcSourceChunkSplitterTest.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,232 @@
/*
* 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.seatunnel.connectors.cdc.base.source.enumerator.splitter;

import org.apache.seatunnel.api.table.type.SeaTunnelDataType;
import org.apache.seatunnel.api.table.type.SeaTunnelRowType;

import org.junit.jupiter.api.Test;

import io.debezium.jdbc.JdbcConnection;
import io.debezium.relational.Column;
import io.debezium.relational.TableId;

import java.sql.SQLException;
import java.util.Arrays;
import java.util.List;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;
import static org.junit.jupiter.api.Assertions.assertTrue;

public class AbstractJdbcSourceChunkSplitterTest {

@Test
public void testEfficientShardingThroughSampling() throws NoSuchMethodException {

UtJdbcSourceChunkSplitter utJdbcSourceChunkSplitter = new UtJdbcSourceChunkSplitter();

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 1, 1, 1, 1, 1}, 1000, 2),
Arrays.asList(ChunkRange.of(null, 1), ChunkRange.of(1, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 1, 1, 1, 1, 1}, 1000, 1),
Arrays.asList(ChunkRange.of(null, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 1, 1, 1, 1, 1}, 1000, 10),
Arrays.asList(ChunkRange.of(null, 1), ChunkRange.of(1, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2}, 1000, 10),
Arrays.asList(ChunkRange.of(null, 1), ChunkRange.of(1, 2), ChunkRange.of(2, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2}, 1000, 1),
Arrays.asList(ChunkRange.of(null, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2}, 1000, 2),
Arrays.asList(ChunkRange.of(null, 1), ChunkRange.of(1, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1}, 1000, 1),
Arrays.asList(ChunkRange.of(null, 1), ChunkRange.of(1, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1}, 1000, 2),
Arrays.asList(ChunkRange.of(null, 1), ChunkRange.of(1, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3}, 1000, 2),
Arrays.asList(ChunkRange.of(null, 2), ChunkRange.of(2, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3}, 1000, 1),
Arrays.asList(ChunkRange.of(null, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3}, 1000, 3),
Arrays.asList(
ChunkRange.of(null, 1),
ChunkRange.of(1, 2),
ChunkRange.of(2, 3),
ChunkRange.of(3, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5}, 1000, 3),
Arrays.asList(ChunkRange.of(null, 2), ChunkRange.of(2, 4), ChunkRange.of(4, null)));
check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5}, 1000, 2),
Arrays.asList(ChunkRange.of(null, 3), ChunkRange.of(3, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5, 6}, 1000, 1),
Arrays.asList(ChunkRange.of(null, null)));

check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5, 6}, 1000, 3),
Arrays.asList(ChunkRange.of(null, 3), ChunkRange.of(3, 5), ChunkRange.of(5, null)));
check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5, 6}, 1000, 4),
Arrays.asList(
ChunkRange.of(null, 2),
ChunkRange.of(2, 4),
ChunkRange.of(4, 5),
ChunkRange.of(5, null)));
check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5, 6}, 1000, 5),
Arrays.asList(
ChunkRange.of(null, 2),
ChunkRange.of(2, 3),
ChunkRange.of(3, 4),
ChunkRange.of(4, 5),
ChunkRange.of(5, null)));
check(
utJdbcSourceChunkSplitter.efficientShardingThroughSampling(
null, new Object[] {1, 2, 3, 4, 5, 6}, 1000, 6),
Arrays.asList(
ChunkRange.of(null, 1),
ChunkRange.of(1, 2),
ChunkRange.of(2, 3),
ChunkRange.of(3, 4),
ChunkRange.of(4, 5),
ChunkRange.of(5, 6),
ChunkRange.of(6, null)));
}

private void check(List<ChunkRange> a, List<ChunkRange> b) {
checkRule(b);
assertEquals(a, b);
}

private void checkRule(List<ChunkRange> a) {
for (int i = 0; i < a.size(); i++) {
if (i == 0) {
assertNull(a.get(i).getChunkStart());
}
if (i == a.size() - 1) {
assertNull(a.get(i).getChunkEnd());
}
// current chunk start should be equal to previous chunk end
if (i > 0) {
assertEquals(a.get(i - 1).getChunkEnd(), a.get(i).getChunkStart());
}
if (i > 0 && i < a.size() - 1) {
// current chunk end should be greater than current chunk start
assertTrue((int) a.get(i).getChunkEnd() > (int) a.get(i).getChunkStart());
}
}
}

public static class UtJdbcSourceChunkSplitter extends AbstractJdbcSourceChunkSplitter {

public UtJdbcSourceChunkSplitter() {
super(null, null);
}

@Override
public Object[] queryMinMax(JdbcConnection jdbc, TableId tableId, String columnName)
throws SQLException {
return new Object[0];
}

@Override
public Object queryMin(
JdbcConnection jdbc, TableId tableId, String columnName, Object excludedLowerBound)
throws SQLException {
return null;
}

@Override
public Object[] sampleDataFromColumn(
JdbcConnection jdbc, TableId tableId, String columnName, int samplingRate)
throws SQLException {
return new Object[0];
}

@Override
public Object queryNextChunkMax(
JdbcConnection jdbc,
TableId tableId,
String columnName,
int chunkSize,
Object includedLowerBound)
throws SQLException {
return null;
}

@Override
public Long queryApproximateRowCnt(JdbcConnection jdbc, TableId tableId)
throws SQLException {
return null;
}

@Override
public String buildSplitScanQuery(
TableId tableId,
SeaTunnelRowType splitKeyType,
boolean isFirstSplit,
boolean isLastSplit) {
return null;
}

@Override
public SeaTunnelDataType<?> fromDbzColumn(Column splitColumn) {
return null;
}
}
}
30 changes: 20 additions & 10 deletions ...main/java/org/apache/seatunnel/connectors/seatunnel/jdbc/source/DynamicChunkSplitter.java
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Original file line number Diff line number Diff line change
Expand Up @@ -247,7 +247,7 @@ private List<ChunkRange> splitEvenlySizedChunks(
return splits;
}

private List<ChunkRange> efficientShardingThroughSampling(
public static List<ChunkRange> efficientShardingThroughSampling(
TablePath tablePath, Object[] sampleData, long approximateRowCnt, int shardCount) {
log.info(
"Use efficient sharding through sampling optimization for table {}, the approximate row count is {}, the shardCount is {}",
Expand All @@ -264,22 +264,32 @@ private List<ChunkRange> efficientShardingThroughSampling(

double approxSamplePerShard = (double) sampleData.length / shardCount;

Object lastEnd = null;
if (approxSamplePerShard <= 1) {

splits.add(ChunkRange.of(null, sampleData[0]));
for (int i = 0; i < sampleData.length - 1; i++) {
splits.add(ChunkRange.of(sampleData[i], sampleData[i + 1]));
lastEnd = sampleData[0];
for (int i = 1; i < sampleData.length; i++) {
// avoid split duplicate data
if (!sampleData[i].equals(lastEnd)) {
splits.add(ChunkRange.of(lastEnd, sampleData[i]));
lastEnd = sampleData[i];
}
}
splits.add(ChunkRange.of(sampleData[sampleData.length - 1], null));

splits.add(ChunkRange.of(lastEnd, null));

} else {
// Calculate the shard boundaries
for (int i = 0; i < shardCount; i++) {
Object chunkStart = i == 0 ? null : sampleData[(int) (i * approxSamplePerShard)];
Object chunkStart = lastEnd;
Object chunkEnd =
i < shardCount - 1
(i < shardCount - 1)
? sampleData[(int) ((i + 1) * approxSamplePerShard)]
: null;
splits.add(ChunkRange.of(chunkStart, chunkEnd));
// avoid split duplicate data
if (i == 0 || i == shardCount - 1 || !Objects.equals(chunkEnd, chunkStart)) {
splits.add(ChunkRange.of(chunkStart, chunkEnd));
lastEnd = chunkEnd;
}
}
}
return splits;
Expand Down Expand Up @@ -444,7 +454,7 @@ private static void prepareDynamicSplitStatement(

@Data
@EqualsAndHashCode
private static class ChunkRange implements Serializable {
public static class ChunkRange implements Serializable {
private final Object chunkStart;
private final Object chunkEnd;

Expand Down
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