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[Improve][Connector-V2] Improve Paimon source split enumerator #6766

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[Improve][Connector-V2] Improve Paimon source split enumerator #6766

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83b0c72
paimon source optimize
Apr 27, 2024
ae76cb4
replace dead links
Apr 27, 2024
76e2593
sr
Apr 28, 2024
eecacd6
Merge branch 'dev' into paimon_source_optimize
Apr 28, 2024
b9c2490
remove pentting splits
May 1, 2024
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114 changes: 72 additions & 42 deletions .../org/apache/seatunnel/connectors/seatunnel/paimon/source/PaimonSourceSplitEnumerator.java
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Original file line number Diff line number Diff line change
Expand Up @@ -19,15 +19,19 @@

import org.apache.seatunnel.api.source.SourceSplitEnumerator;

import org.apache.commons.collections.map.HashedMap;
import org.apache.paimon.table.Table;
import org.apache.paimon.table.source.Split;

import lombok.extern.slf4j.Slf4j;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Collectors;

Expand All @@ -39,36 +43,50 @@ public class PaimonSourceSplitEnumerator
/** Source split enumerator context */
private final Context<PaimonSourceSplit> context;

/** The splits that has assigned */
private final Set<PaimonSourceSplit> assignedSplit;
private final Set<PaimonSourceSplit> pendingSplits = new HashSet<>();

/** The splits that have not assigned */
private Set<PaimonSourceSplit> pendingSplit;
private Map<Integer, Set<PaimonSourceSplit>> assignedSplits;

private volatile boolean shouldEnumerate;

private final Object stateLock = new Object();

/** The table that wants to read */
private final Table table;

public PaimonSourceSplitEnumerator(Context<PaimonSourceSplit> context, Table table) {
this.context = context;
this.table = table;
this.assignedSplit = new HashSet<>();
this(context, table, null);
}

public PaimonSourceSplitEnumerator(
Context<PaimonSourceSplit> context, Table table, PaimonSourceState sourceState) {
this.context = context;
this.table = table;
this.assignedSplit = sourceState.getAssignedSplits();
this.shouldEnumerate = (sourceState == null || sourceState.isShouldEnumerate());
this.assignedSplits = new HashedMap();
if (sourceState != null) {
this.assignedSplits.putAll(sourceState.getAssignedSplits());
}
}

@Override
public void open() {
this.pendingSplit = new HashSet<>();
this.pendingSplits.addAll(getTableSplits());
}

@Override
public void run() throws Exception {
// do nothing
Set<Integer> readers = context.registeredReaders();
if (shouldEnumerate) {
synchronized (stateLock) {
addAssignSplit(pendingSplits);
shouldEnumerate = false;
}
assignSplit(readers);
}
log.debug(
"No more splits to assign." + " Sending NoMoreSplitsEvent to reader {}.", readers);
readers.forEach(context::signalNoMoreSplits);
}

@Override
Expand All @@ -79,25 +97,29 @@ public void close() throws IOException {
@Override
public void addSplitsBack(List<PaimonSourceSplit> splits, int subtaskId) {
if (!splits.isEmpty()) {
pendingSplit.addAll(splits);
assignSplit(subtaskId);
addAssignSplit(splits);
assignSplit(Collections.singletonList(subtaskId));
}
}

@Override
public int currentUnassignedSplitSize() {
return pendingSplit.size();
return pendingSplits.size();
}

@Override
public void registerReader(int subtaskId) {
pendingSplit = getTableSplits();
assignSplit(subtaskId);
log.debug("Register reader {} to PaimonSourceSplitEnumerator.", subtaskId);
if (!pendingSplits.isEmpty()) {
assignSplit(Collections.singletonList(subtaskId));
}
}

@Override
public PaimonSourceState snapshotState(long checkpointId) throws Exception {
return new PaimonSourceState(assignedSplit);
synchronized (stateLock) {
return new PaimonSourceState(assignedSplits, shouldEnumerate);
}
}

@Override
Expand All @@ -110,36 +132,44 @@ public void handleSplitRequest(int subtaskId) {
// do nothing
}

private void addAssignSplit(Collection<PaimonSourceSplit> splits) {
int readerCount = context.currentParallelism();
for (PaimonSourceSplit split : splits) {
int ownerReader = getSplitOwner(split.splitId(), readerCount);
log.info("Assigning {} to {} reader.", split.getSplit().toString(), ownerReader);
// remove the assigned splits from pending splits
pendingSplits.remove(split);
// save the state of assigned splits
assignedSplits.computeIfAbsent(ownerReader, r -> new HashSet<>()).add(split);
}
}

/** Assign split by reader task id */
private void assignSplit(int taskId) {
ArrayList<PaimonSourceSplit> currentTaskSplits = new ArrayList<>();
if (context.currentParallelism() == 1) {
// if parallelism == 1, we should assign all the splits to reader
currentTaskSplits.addAll(pendingSplit);
} else {
// if parallelism > 1, according to hashCode of split's id to determine whether to
// allocate the current task
for (PaimonSourceSplit fileSourceSplit : pendingSplit) {
final int splitOwner =
getSplitOwner(fileSourceSplit.splitId(), context.currentParallelism());
if (splitOwner == taskId) {
currentTaskSplits.add(fileSourceSplit);
private void assignSplit(Collection<Integer> readers) {

log.debug("Assign pendingSplits to readers {}", readers);

for (int reader : readers) {
Set<PaimonSourceSplit> assignmentForReader = assignedSplits.remove(reader);
if (assignmentForReader != null && !assignmentForReader.isEmpty()) {
log.info(
"Assign splits {} to reader {}",
assignmentForReader.stream()
.map(p -> p.getSplit().toString())
.collect(Collectors.joining(",")),
reader);
try {
context.assignSplit(reader, new ArrayList<>(assignmentForReader));
} catch (Exception e) {
log.error(
"Failed to assign splits {} to reader {}",
assignmentForReader,
reader,
e);
pendingSplits.addAll(assignmentForReader);
}
}
}
// assign splits
context.assignSplit(taskId, currentTaskSplits);
// save the state of assigned splits
assignedSplit.addAll(currentTaskSplits);
// remove the assigned splits from pending splits
currentTaskSplits.forEach(split -> pendingSplit.remove(split));
log.info(
"SubTask {} is assigned to [{}]",
taskId,
currentTaskSplits.stream()
.map(PaimonSourceSplit::splitId)
.collect(Collectors.joining(",")));
context.signalNoMoreSplits(taskId);
}

/** Get all splits of table */
Expand Down
18 changes: 8 additions & 10 deletions .../main/java/org/apache/seatunnel/connectors/seatunnel/paimon/source/PaimonSourceState.java
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -17,21 +17,19 @@

package org.apache.seatunnel.connectors.seatunnel.paimon.source;

import lombok.AllArgsConstructor;
import lombok.Getter;

import java.io.Serializable;
import java.util.Map;
import java.util.Set;

@AllArgsConstructor
@Getter
/** Paimon connector source state, saves the splits has assigned to readers. */
public class PaimonSourceState implements Serializable {

private static final long serialVersionUID = 1L;

private final Set<PaimonSourceSplit> assignedSplits;

public PaimonSourceState(Set<PaimonSourceSplit> assignedSplits) {
this.assignedSplits = assignedSplits;
}

public Set<PaimonSourceSplit> getAssignedSplits() {
return assignedSplits;
}
private final Map<Integer, Set<PaimonSourceSplit>> assignedSplits;
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Why change Set to Map here? Any considerations?

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Why change Set to Map here? Any considerations?

I think there is a small optimization，avoid the traversal operation when removing the allocated PaimonSourceSplit from pendingSplit. use set like FileSourceSplitEnumerator, a nested loop will be formed in the FileSourceSplitEnumerator#run() method.

private boolean shouldEnumerate;
}