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[kv] Avoid unnecessary RocksDB flushes during Tablet Server shutdown #3807

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[kv] Avoid unnecessary RocksDB flushes during Tablet Server shutdown #3807

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27 changes: 27 additions & 0 deletions fluss-server/src/main/java/org/apache/fluss/server/kv/KvCloseMode.java
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@@ -0,0 +1,27 @@
/*
* 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.server.kv;

/** Defines whether closing a KV tablet must persist its current local RocksDB state. */
public enum KvCloseMode {
/** Preserve the existing local-reopen behavior by allowing RocksDB to flush on close. */
PRESERVE_LOCAL_STATE,

/** Skip flushing data that recovery will rebuild from a snapshot and changelog. */
DISCARD_UNPERSISTED_STATE
}
22 changes: 17 additions & 5 deletions fluss-server/src/main/java/org/apache/fluss/server/kv/KvManager.java
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Expand Up @@ -63,6 +63,7 @@
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;

Expand Down Expand Up @@ -203,10 +204,17 @@ public void startup() {
}

public void shutdown() {
LOG.info("Shutting down KvManager");
shutdown(KvCloseMode.PRESERVE_LOCAL_STATE);
}

public void shutdown(KvCloseMode closeMode) {
Objects.requireNonNull(closeMode, "closeMode");
LOG.info("Shutting down KvManager with close mode {}.", closeMode);
isShutdown = true;
List<KvTablet> kvs = new ArrayList<>(currentKvs.values());
closeTabletsConcurrently(kvs, "kv-tablet-closing", this::closeKvTablet).join();
closeTabletsConcurrently(
kvs, "kv-tablet-closing", kvTablet -> closeKvTablet(kvTablet, closeMode))
.join();
arrowBufferAllocator.close();
memorySegmentPool.close();
if (sharedRocksDBRateLimiter != null) {
Expand All @@ -215,11 +223,15 @@ public void shutdown() {
LOG.info("Shut down KvManager complete.");
}

private void closeKvTablet(KvTablet kvTablet) {
private void closeKvTablet(KvTablet kvTablet, KvCloseMode closeMode) {
try {
kvTablet.close();
kvTablet.close(closeMode);
} catch (Exception e) {
LOG.warn("Exception while closing kv tablet {}.", kvTablet.getTableBucket(), e);
LOG.warn(
"Exception while closing kv tablet {} with mode {}.",
kvTablet.getTableBucket(),
closeMode,
e);
}
}

Expand Down
14 changes: 11 additions & 3 deletions fluss-server/src/main/java/org/apache/fluss/server/kv/KvTablet.java
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Expand Up @@ -842,7 +842,15 @@ public KvBatchWriter createKvBatchWriter() {
}

public void close() throws Exception {
LOG.debug("close kv tablet {} for table {}.", tableBucket, physicalPath);
close(KvCloseMode.PRESERVE_LOCAL_STATE);
}

public void close(KvCloseMode closeMode) throws Exception {
LOG.debug(
"Close kv tablet {} for table {} with mode {}.",
tableBucket,
physicalPath,
closeMode);
inWriteLock(
kvLock,
() -> {
Expand All @@ -852,7 +860,7 @@ public void close() throws Exception {
// Note: RocksDB metrics lifecycle is managed by TableMetricGroup
// No need to close it here
if (rocksDBKv != null) {
rocksDBKv.close();
rocksDBKv.close(closeMode);
}
isClosed = true;
});
Expand All @@ -864,7 +872,7 @@ public void drop() throws Exception {
kvLock,
() -> {
// first close the kv.
close();
close(KvCloseMode.DISCARD_UNPERSISTED_STATE);
// then delete the directory.
FileUtils.deleteDirectory(kvTabletDir);
});
Expand Down
63 changes: 45 additions & 18 deletions fluss-server/src/main/java/org/apache/fluss/server/kv/rocksdb/RocksDBKv.java
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Expand Up @@ -17,17 +17,20 @@

package org.apache.fluss.server.kv.rocksdb;

import org.apache.fluss.annotation.VisibleForTesting;
import org.apache.fluss.exception.FlussRuntimeException;
import org.apache.fluss.metrics.Counter;
import org.apache.fluss.metrics.Histogram;
import org.apache.fluss.rocksdb.RocksDBOperationUtils;
import org.apache.fluss.server.kv.KvCloseMode;
import org.apache.fluss.server.utils.ResourceGuard;
import org.apache.fluss.utils.BytesUtils;
import org.apache.fluss.utils.IOUtils;

import org.rocksdb.Cache;
import org.rocksdb.ColumnFamilyHandle;
import org.rocksdb.ColumnFamilyOptions;
import org.rocksdb.MutableDBOptions;
import org.rocksdb.ReadOptions;
import org.rocksdb.RocksDB;
import org.rocksdb.RocksDBException;
Expand All @@ -40,6 +43,7 @@
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;

/** A wrapper for the operation of {@link org.rocksdb.RocksDB}. */
public class RocksDBKv implements AutoCloseable {
Expand Down Expand Up @@ -178,6 +182,13 @@ public void checkIfRocksDBClosed() {

@Override
public void close() throws Exception {
close(KvCloseMode.PRESERVE_LOCAL_STATE);
}

/** Closes this RocksDB KV instance using the provided persistence mode. */
public void close(KvCloseMode closeMode) throws Exception {
Objects.requireNonNull(closeMode);

if (this.closed) {
return;
}
Expand All @@ -188,29 +199,45 @@ public void close() throws Exception {
// parallel.
rocksDBResourceGuard.close();

// IMPORTANT: null reference to signal potential async checkpoint workers that the db was
// disposed, as
// working on the disposed object results in SEGFAULTS.
if (db != null) {
RocksDBException avoidFlushFailure = null;
try {
if (closeMode == KvCloseMode.DISCARD_UNPERSISTED_STATE) {
setAvoidFlushDuringShutdown();
}
} catch (RocksDBException e) {
avoidFlushFailure = e;
} finally {
// IMPORTANT: null reference to signal potential async checkpoint workers that the db
// was disposed, as working on the disposed object results in SEGFAULTS.
if (db != null) {

// RocksDB's native memory management requires that *all* CFs (including default)
// are closed before the DB is closed. See:
// https://github.com/facebook/rocksdb/wiki/RocksJava-Basics#opening-a-database-with-column-families
// Start with default CF ...
List<ColumnFamilyOptions> columnFamilyOptions = new ArrayList<>();
RocksDBOperationUtils.addColumnFamilyOptionsToCloseLater(
columnFamilyOptions, defaultColumnFamilyHandle);
IOUtils.closeQuietly(defaultColumnFamilyHandle);

// RocksDB's native memory management requires that *all* CFs (including default) are
// closed before the
// DB is closed. See:
// https://github.com/facebook/rocksdb/wiki/RocksJava-Basics#opening-a-database-with-column-families
// Start with default CF ...
List<ColumnFamilyOptions> columnFamilyOptions = new ArrayList<>();
RocksDBOperationUtils.addColumnFamilyOptionsToCloseLater(
columnFamilyOptions, defaultColumnFamilyHandle);
IOUtils.closeQuietly(defaultColumnFamilyHandle);
// ... and finally close the DB instance ...
IOUtils.closeQuietly(db);

// ... and finally close the DB instance ...
IOUtils.closeQuietly(db);
columnFamilyOptions.forEach(IOUtils::closeQuietly);

columnFamilyOptions.forEach(IOUtils::closeQuietly);
IOUtils.closeQuietly(optionsContainer);
}
this.closed = true;
}

IOUtils.closeQuietly(optionsContainer);
if (avoidFlushFailure != null) {
throw avoidFlushFailure;
}
this.closed = true;
}

@VisibleForTesting
void setAvoidFlushDuringShutdown() throws RocksDBException {
db.setDBOptions(MutableDBOptions.builder().setAvoidFlushDuringShutdown(true).build());
}

public RocksDB getDb() {
Expand Down
12 changes: 9 additions & 3 deletions fluss-server/src/main/java/org/apache/fluss/server/tablet/TabletServer.java
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Expand Up @@ -39,6 +39,7 @@
import org.apache.fluss.server.authorizer.AuthorizerLoader;
import org.apache.fluss.server.coordinator.LakeCatalogDynamicLoader;
import org.apache.fluss.server.coordinator.MetadataManager;
import org.apache.fluss.server.kv.KvCloseMode;
import org.apache.fluss.server.kv.KvManager;
import org.apache.fluss.server.kv.scan.ScannerManager;
import org.apache.fluss.server.kv.snapshot.DefaultCompletedKvSnapshotCommitter;
Expand Down Expand Up @@ -571,9 +572,7 @@ void shutdownReplicaManager() throws InterruptedException {

@VisibleForTesting
void shutdownTabletManagers() throws IOException {
if (kvManager != null) {
kvManager.shutdown();
}
shutdownKvManager(KvCloseMode.DISCARD_UNPERSISTED_STATE);

if (remoteLogManager != null) {
remoteLogManager.close();
Expand All @@ -584,6 +583,13 @@ void shutdownTabletManagers() throws IOException {
}
}

@VisibleForTesting
void shutdownKvManager(KvCloseMode closeMode) {
if (kvManager != null) {
kvManager.shutdown(closeMode);
}
}

private void controlledShutDown() {
long startTime = System.currentTimeMillis();
LOG.info("Starting controlled shutdown.");
Expand Down
49 changes: 48 additions & 1 deletion fluss-server/src/test/java/org/apache/fluss/server/kv/KvManagerTest.java
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Expand Up @@ -60,6 +60,7 @@

import java.io.File;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
import java.time.Duration;
import java.util.ArrayList;
import java.util.Arrays;
Expand Down Expand Up @@ -232,6 +233,29 @@ void testRecoveryAfterKvManagerShutDown(String partitionName) throws Exception {
assertThat(kv2.multiGet(kv2Keys)).containsExactlyElementsOf(kv2Values);
}

@ParameterizedTest
@MethodSource("partitionProvider")
void testDiscardShutdownDoesNotPersistUnflushedState(String partitionName) throws Exception {
initTableBuckets(partitionName);
KvTablet kv = getOrCreateKv(tablePath1, partitionName, tableBucket1);
byte[] key = "discarded-key".getBytes(StandardCharsets.UTF_8);
put(kv, kvRecordFactory.ofRecord(key, new Object[] {1, "value"}));

kvManager.shutdown(KvCloseMode.DISCARD_UNPERSISTED_STATE);
kvManager =
KvManager.create(
conf,
zkClient,
logManager,
TestingMetricGroups.TABLET_SERVER_METRICS,
localDiskManager);
kvManager.startup();

KvTablet reopened = getOrCreateKv(tablePath1, partitionName, tableBucket1);
assertThat(reopened.multiGet(Collections.singletonList(key)))
.containsExactly((byte[]) null);
}

@ParameterizedTest
@MethodSource("partitionProvider")
void testRecoveryWithSchemaChange(String partitionName) throws Exception {
Expand Down Expand Up @@ -317,13 +341,16 @@ void testSameTableNameInDifferentDb(String partitionName) throws Exception {
void testDropKv(String partitionName) throws Exception {
initTableBuckets(partitionName);
KvTablet kv1 = getOrCreateKv(tablePath1, partitionName, tableBucket1);
byte[] key = "dropped-key".getBytes(StandardCharsets.UTF_8);
put(kv1, kvRecordFactory.ofRecord(key, new Object[] {1, "old"}));
kvManager.dropKv(kv1.getTableBucket());

assertThat(kv1.getKvTabletDir()).doesNotExist();
assertThat(kvManager.getKv(tableBucket1)).isNotPresent();

kv1 = getOrCreateKv(tablePath1, partitionName, tableBucket1);
assertThat(kv1.getKvTabletDir()).exists();
assertThat(kv1.multiGet(Collections.singletonList(key))).containsExactly((byte[]) null);
assertThat(kvManager.getKv(tableBucket1)).isPresent();
}

Expand All @@ -334,6 +361,26 @@ void testGetNonExistentKv() {
assertThat(kv).isNotPresent();
}

@Test
void testShutdownRejectsNullCloseModeBeforeClosingTablets() throws Exception {
initTableBuckets(null);
KvTablet kv = getOrCreateKv(tablePath1, null, tableBucket1);
byte[] key = "still-usable-key".getBytes(StandardCharsets.UTF_8);
KvRecord record = kvRecordFactory.ofRecord(key, new Object[] {1, "value"});
put(kv, record);

assertThatThrownBy(() -> kvManager.shutdown(null))
.isInstanceOf(NullPointerException.class)
.hasMessage("closeMode");

verifyMultiGet(kv, key, valueOf(record));

kvManager.shutdown();
assertThatThrownBy(kv.getRocksDBKv()::checkIfRocksDBClosed)
.isInstanceOf(FlussRuntimeException.class);
kvManager = null;
}

@Test
void testShutdownClosesKvTabletsConcurrently() throws Exception {
int maxClosingThreads = 2;
Expand All @@ -352,7 +399,7 @@ void testShutdownClosesKvTabletsConcurrently() throws Exception {
KvManager managerToShutdown = kvManager;
kvManager = null;
ExecutorService shutdownExecutor = Executors.newSingleThreadExecutor();
Future<?> shutdownFuture = shutdownExecutor.submit(managerToShutdown::shutdown);
Future<?> shutdownFuture = shutdownExecutor.submit(() -> managerToShutdown.shutdown());
try {
waitUntil(
() ->
Expand Down
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