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The following commit(s) were added to refs/heads/dev by this push:
new 71ab9e32c3 [Improve][connector-clickhouse] Improved clickhouse source
enumerator splits allocation algorithm for subtasks (#10866)
71ab9e32c3 is described below
commit 71ab9e32c3bc6ab20c94f176125098cc4fbc979f
Author: JeremyXin <[email protected]>
AuthorDate: Tue May 12 22:47:59 2026 +0800
[Improve][connector-clickhouse] Improved clickhouse source enumerator
splits allocation algorithm for subtasks (#10866)
---
.../split/ClickhouseSourceSplitEnumerator.java | 19 +++-
.../split/ClickhouseSourceSplitEnumeratorTest.java | 109 +++++++++++++++++++++
2 files changed, 124 insertions(+), 4 deletions(-)
diff --git
a/seatunnel-connectors-v2/connector-clickhouse/src/main/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumerator.java
b/seatunnel-connectors-v2/connector-clickhouse/src/main/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumerator.java
index fcf85fa226..35e88dbaf0 100644
---
a/seatunnel-connectors-v2/connector-clickhouse/src/main/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumerator.java
+++
b/seatunnel-connectors-v2/connector-clickhouse/src/main/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumerator.java
@@ -41,11 +41,14 @@ import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
+import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Collectors;
import java.util.stream.IntStream;
public class ClickhouseSourceSplitEnumerator
@@ -60,6 +63,7 @@ public class ClickhouseSourceSplitEnumerator
private final Context<ClickhouseSourceSplit> context;
private final Map<TablePath, List<ClickHouseNode>> nodesMap;
private final Object stateLock = new Object();
+ private final AtomicInteger assignCount = new AtomicInteger(0);
public ClickhouseSourceSplitEnumerator(
Context<ClickhouseSourceSplit> context,
@@ -198,8 +202,15 @@ public class ClickhouseSourceSplitEnumerator
private void addPendingSplit(Collection<ClickhouseSourceSplit> splits) {
int readerCount = context.currentParallelism();
- for (ClickhouseSourceSplit split : splits) {
- int ownerReader = getSplitOwner(split.splitId(), readerCount);
+
+ List<ClickhouseSourceSplit> sortedSplits =
+ splits.stream()
+
.sorted(Comparator.comparing(ClickhouseSourceSplit::getSplitId))
+ .collect(Collectors.toList());
+
+ assignCount.set(0);
+ for (ClickhouseSourceSplit split : sortedSplits) {
+ int ownerReader = getSplitOwner(assignCount.getAndIncrement(),
readerCount);
LOG.debug("Assigning {} to {} reader.", split, ownerReader);
pendingSplit.computeIfAbsent(ownerReader, r -> new
ArrayList<>()).add(split);
@@ -210,8 +221,8 @@ public class ClickhouseSourceSplitEnumerator
pendingSplit.computeIfAbsent(ownerReader, r -> new
ArrayList<>()).addAll(splits);
}
- private static int getSplitOwner(String tp, int numReaders) {
- return (tp.hashCode() & Integer.MAX_VALUE) % numReaders;
+ private static int getSplitOwner(int assignCount, int numReaders) {
+ return assignCount % numReaders;
}
private List<Shard> getClusterShardList(
diff --git
a/seatunnel-connectors-v2/connector-clickhouse/src/test/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumeratorTest.java
b/seatunnel-connectors-v2/connector-clickhouse/src/test/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumeratorTest.java
new file mode 100644
index 0000000000..107a7b7e77
--- /dev/null
+++
b/seatunnel-connectors-v2/connector-clickhouse/src/test/java/org/apache/seatunnel/connectors/seatunnel/clickhouse/source/split/ClickhouseSourceSplitEnumeratorTest.java
@@ -0,0 +1,109 @@
+/*
+ * 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.seatunnel.clickhouse.source.split;
+
+import org.apache.seatunnel.api.common.metrics.MetricsContext;
+import org.apache.seatunnel.api.event.EventListener;
+import org.apache.seatunnel.api.source.SourceEvent;
+import org.apache.seatunnel.api.source.SourceSplitEnumerator;
+import
org.apache.seatunnel.connectors.seatunnel.clickhouse.state.ClickhouseSourceState;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+import java.lang.reflect.Method;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+public class ClickhouseSourceSplitEnumeratorTest {
+
+ @Test
+ public void shouldBalanceSplitsEvenlyAcrossReaders() throws Exception {
+ TestingContext context = new TestingContext(4);
+
+ ClickhouseSourceSplitEnumerator enumerator =
+ new ClickhouseSourceSplitEnumerator(
+ context, null, Collections.emptyMap(),
Collections.emptyMap());
+
+ Method addPendingSplit =
+ ClickhouseSourceSplitEnumerator.class.getDeclaredMethod(
+ "addPendingSplit", java.util.Collection.class);
+ addPendingSplit.setAccessible(true);
+ addPendingSplit.invoke(enumerator, buildSplits(10));
+
+ ClickhouseSourceState state = enumerator.snapshotState(1L);
+ Map<Integer, List<ClickhouseSourceSplit>> pendingSplit =
state.getPendingSplit();
+
+ Assertions.assertEquals(4, pendingSplit.size());
+ Assertions.assertEquals(3, pendingSplit.get(0).size());
+ Assertions.assertEquals(3, pendingSplit.get(1).size());
+ Assertions.assertEquals(2, pendingSplit.get(2).size());
+ Assertions.assertEquals(2, pendingSplit.get(3).size());
+ }
+
+ private List<ClickhouseSourceSplit> buildSplits(int size) {
+ List<ClickhouseSourceSplit> splits = new ArrayList<>();
+ for (int i = 0; i < size; i++) {
+ splits.add(
+ new ClickhouseSourceSplit(
+ null, null, Collections.emptyList(), null, null,
"split-" + i));
+ }
+ return splits;
+ }
+
+ private static class TestingContext
+ implements SourceSplitEnumerator.Context<ClickhouseSourceSplit> {
+ private final int parallelism;
+
+ private TestingContext(int parallelism) {
+ this.parallelism = parallelism;
+ }
+
+ @Override
+ public int currentParallelism() {
+ return parallelism;
+ }
+
+ @Override
+ public Set<Integer> registeredReaders() {
+ return Collections.emptySet();
+ }
+
+ @Override
+ public void assignSplit(int subtaskId, List<ClickhouseSourceSplit>
splits) {}
+
+ @Override
+ public void signalNoMoreSplits(int subtask) {}
+
+ @Override
+ public void sendEventToSourceReader(int subtaskId, SourceEvent event)
{}
+
+ @Override
+ public MetricsContext getMetricsContext() {
+ return null;
+ }
+
+ @Override
+ public EventListener getEventListener() {
+ return null;
+ }
+ }
+}
