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Posted to issues@ozone.apache.org by GitBox <gi...@apache.org> on 2021/03/03 11:08:09 UTC
[GitHub] [ozone] bshashikant commented on a change in pull request #1980: HDDS-4651: Distributed Sequence ID Gen.
bshashikant commented on a change in pull request #1980:
URL: https://github.com/apache/ozone/pull/1980#discussion_r586279853
##########
File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/ha/SequenceIdGen.java
##########
@@ -0,0 +1,284 @@
+/*
Review comment:
can we change the class name SequenceIdGen.java ---> SequenceIdGenerator.java
##########
File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/ha/SequenceIdGen.java
##########
@@ -0,0 +1,284 @@
+/*
+ * 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
+ * <p>
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * <p>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.hadoop.hdds.scm.ha;
+
+import com.google.common.base.Preconditions;
+import org.apache.hadoop.hdds.conf.ConfigurationSource;
+import org.apache.hadoop.hdds.scm.metadata.Replicate;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.lang.reflect.Proxy;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static org.apache.hadoop.hdds.protocol.proto.SCMRatisProtocol.RequestType.SEQUENCE_ID;
+import static org.apache.hadoop.hdds.scm.ScmConfigKeys.OZONE_SCM_SEQUENCE_ID_BATCH_SIZE;
+import static org.apache.hadoop.hdds.scm.ScmConfigKeys.OZONE_SCM_SEQUENCE_ID_BATCH_SIZE_DEFAULT;
+import static org.apache.hadoop.ozone.OzoneConsts.SEQUENCE_ID_KEY;
+
+/**
+ * After SCM starts, set lastId = 0, nextId = lastId + 1.
+ * The first getNextId() call triggers SCM to load lastId from rocksDB,
+ * and allocate a new batch.
+ *
+ * In order to maintain monotonicity, for Ratis based SequenceIdGen,
+ * when becoming leader, SCM invalidates un-exhausted id batch by setting
+ * nextId = lastId + 1, so that a new leader will reload lastId from
+ * rocksDB and allocate a new batch when receiving its first getNextId() call.
+ */
+public class SequenceIdGen {
+ private static final Logger LOG =
+ LoggerFactory.getLogger(SequenceIdGen.class);
+ private static final long INVALID_SEQUENCE_ID = 0;
+
+ private long lastId = INVALID_SEQUENCE_ID;
+ private long nextId = lastId + 1;
+
+ private final Lock lock;
+ private final long batchSize;
+ private final StateManager stateManager;
+
+ /**
+ * @param conf : conf
+ * @param scmhaManager : null if non-Ratis based
+ * @param sequenceIdTable : sequenceIdTable
+ */
+ public SequenceIdGen(ConfigurationSource conf, SCMHAManager scmhaManager,
+ Table<String, Long> sequenceIdTable) {
+ this.lock = new ReentrantLock();
+ this.batchSize = conf.getInt(OZONE_SCM_SEQUENCE_ID_BATCH_SIZE,
+ OZONE_SCM_SEQUENCE_ID_BATCH_SIZE_DEFAULT);
+
+ if (SCMHAUtils.isSCMHAEnabled(conf)) {
+ this.stateManager = new StateManagerRatisImpl.Builder()
+ .setRatisServer(scmhaManager.getRatisServer())
+ .setDBTransactionBuffer(scmhaManager.getDBTransactionBuffer())
+ .setSequenceIdTable(sequenceIdTable)
+ .build();
+ } else {
+ this.stateManager = new StateManagerNonRatisImpl(sequenceIdTable);
+ }
+ }
+
+ /**
+ * @return next distributed sequence id.
+ */
+ public long getNextId() {
+ lock.lock();
+ try {
+ if (nextId <= lastId) {
+ return nextId++;
+ }
+
+ Preconditions.checkArgument(nextId == lastId + 1);
+ while (true) {
+ Long prevLastId = lastId;
+ nextId = prevLastId + 1;
+ lastId += batchSize;
+
+ if (stateManager.allocateBatch(prevLastId, lastId)) {
+ LOG.info("Allocate a batch, change lastId from {} to {}.",
+ prevLastId, lastId);
+ break;
+ }
+
+ // reload lastId from RocksDB.
+ lastId = stateManager.getLastId();
+ }
+
+ Preconditions.checkArgument(nextId <= lastId);
+ return nextId++;
+
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Invalidate any un-exhausted batch, next getNextId() call will
+ * allocate a new batch.
+ */
+ public void invalidateBatch() {
+ lock.lock();
+ try {
+ nextId = lastId + 1;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Maintain SequenceIdTable in RocksDB.
+ */
+ interface StateManager {
+ /**
+ * Compare And Swap lastId saved in db from expectedLastId to newLastId.
+ * If based on Ratis, it will submit a raft client request.
+ *
+ * @param expectedLastId : the expected lastId saved in db
+ * @param newLastId : the new lastId to save in db
+ * @return : result of the C.A.S.
+ */
+ @Replicate
+ Boolean allocateBatch(Long expectedLastId, Long newLastId);
+
+ /**
+ * @return lastId saved in db
+ */
+ Long getLastId();
+ }
+
+ /**
+ * Ratis based StateMachine, db operations are queued in
+ * DBTransactionBuffer until a snapshot is taken.
+ */
+ static final class StateManagerRatisImpl implements StateManager {
Review comment:
StateManagerRatisImpl -> StateManagerHAImpl
##########
File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/ha/SequenceIdGen.java
##########
@@ -0,0 +1,284 @@
+/*
+ * 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
+ * <p>
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * <p>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.hadoop.hdds.scm.ha;
+
+import com.google.common.base.Preconditions;
+import org.apache.hadoop.hdds.conf.ConfigurationSource;
+import org.apache.hadoop.hdds.scm.metadata.Replicate;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.lang.reflect.Proxy;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static org.apache.hadoop.hdds.protocol.proto.SCMRatisProtocol.RequestType.SEQUENCE_ID;
+import static org.apache.hadoop.hdds.scm.ScmConfigKeys.OZONE_SCM_SEQUENCE_ID_BATCH_SIZE;
+import static org.apache.hadoop.hdds.scm.ScmConfigKeys.OZONE_SCM_SEQUENCE_ID_BATCH_SIZE_DEFAULT;
+import static org.apache.hadoop.ozone.OzoneConsts.SEQUENCE_ID_KEY;
+
+/**
+ * After SCM starts, set lastId = 0, nextId = lastId + 1.
+ * The first getNextId() call triggers SCM to load lastId from rocksDB,
+ * and allocate a new batch.
+ *
+ * In order to maintain monotonicity, for Ratis based SequenceIdGen,
+ * when becoming leader, SCM invalidates un-exhausted id batch by setting
+ * nextId = lastId + 1, so that a new leader will reload lastId from
+ * rocksDB and allocate a new batch when receiving its first getNextId() call.
+ */
+public class SequenceIdGen {
+ private static final Logger LOG =
+ LoggerFactory.getLogger(SequenceIdGen.class);
+ private static final long INVALID_SEQUENCE_ID = 0;
+
+ private long lastId = INVALID_SEQUENCE_ID;
+ private long nextId = lastId + 1;
+
+ private final Lock lock;
+ private final long batchSize;
+ private final StateManager stateManager;
+
+ /**
+ * @param conf : conf
+ * @param scmhaManager : null if non-Ratis based
+ * @param sequenceIdTable : sequenceIdTable
+ */
+ public SequenceIdGen(ConfigurationSource conf, SCMHAManager scmhaManager,
+ Table<String, Long> sequenceIdTable) {
+ this.lock = new ReentrantLock();
+ this.batchSize = conf.getInt(OZONE_SCM_SEQUENCE_ID_BATCH_SIZE,
+ OZONE_SCM_SEQUENCE_ID_BATCH_SIZE_DEFAULT);
+
+ if (SCMHAUtils.isSCMHAEnabled(conf)) {
+ this.stateManager = new StateManagerRatisImpl.Builder()
+ .setRatisServer(scmhaManager.getRatisServer())
+ .setDBTransactionBuffer(scmhaManager.getDBTransactionBuffer())
+ .setSequenceIdTable(sequenceIdTable)
+ .build();
+ } else {
+ this.stateManager = new StateManagerNonRatisImpl(sequenceIdTable);
+ }
+ }
+
+ /**
+ * @return next distributed sequence id.
+ */
+ public long getNextId() {
+ lock.lock();
+ try {
+ if (nextId <= lastId) {
+ return nextId++;
+ }
+
+ Preconditions.checkArgument(nextId == lastId + 1);
+ while (true) {
+ Long prevLastId = lastId;
+ nextId = prevLastId + 1;
+ lastId += batchSize;
+
+ if (stateManager.allocateBatch(prevLastId, lastId)) {
+ LOG.info("Allocate a batch, change lastId from {} to {}.",
+ prevLastId, lastId);
+ break;
+ }
+
+ // reload lastId from RocksDB.
+ lastId = stateManager.getLastId();
+ }
+
+ Preconditions.checkArgument(nextId <= lastId);
+ return nextId++;
+
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Invalidate any un-exhausted batch, next getNextId() call will
+ * allocate a new batch.
+ */
+ public void invalidateBatch() {
+ lock.lock();
+ try {
+ nextId = lastId + 1;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Maintain SequenceIdTable in RocksDB.
+ */
+ interface StateManager {
+ /**
+ * Compare And Swap lastId saved in db from expectedLastId to newLastId.
+ * If based on Ratis, it will submit a raft client request.
+ *
+ * @param expectedLastId : the expected lastId saved in db
+ * @param newLastId : the new lastId to save in db
+ * @return : result of the C.A.S.
+ */
+ @Replicate
+ Boolean allocateBatch(Long expectedLastId, Long newLastId);
+
+ /**
+ * @return lastId saved in db
+ */
+ Long getLastId();
+ }
+
+ /**
+ * Ratis based StateMachine, db operations are queued in
+ * DBTransactionBuffer until a snapshot is taken.
+ */
+ static final class StateManagerRatisImpl implements StateManager {
+ private final Table<String, Long> sequenceIdTable;
+ private final DBTransactionBuffer transactionBuffer;
+ private volatile Long lastId;
+
+ private StateManagerRatisImpl(Table<String, Long> sequenceIdTable,
+ DBTransactionBuffer trxBuffer) {
+ this.sequenceIdTable = sequenceIdTable;
+ this.transactionBuffer = trxBuffer;
+
+ try {
+ lastId = this.sequenceIdTable.get(SEQUENCE_ID_KEY);
+ } catch (IOException ioe) {
+ throw new RuntimeException("Failed to get lastId from db", ioe);
+ }
+ if (lastId == null) {
+ lastId = INVALID_SEQUENCE_ID;
+ }
+ LOG.info("Init Ratis based SequenceIdGen, lastId is {}.", lastId);
+ }
+
+ @Override
+ public Boolean allocateBatch(Long expectedLastId, Long newLastId) {
+ if (!lastId.equals(expectedLastId)) {
+ LOG.warn("Failed to allocate a batch, expected lastId is {}," +
+ " actual lastId is {}.", expectedLastId, lastId);
+ return false;
+ }
+
+ try {
+ sequenceIdTable.putWithBatch(transactionBuffer
+ .getCurrentBatchOperation(), SEQUENCE_ID_KEY, newLastId);
+ } catch (IOException ioe) {
+ throw new RuntimeException("Failed to put lastId to Batch", ioe);
+ }
+
+ lastId = newLastId;
+ return true;
+ }
+
+ @Override
+ public Long getLastId() {
+ return lastId;
+ }
+
+ /**
+ * Builder for Ratis based StateManager.
+ */
+ public static class Builder {
+ private Table<String, Long> table;
+ private DBTransactionBuffer buffer;
+ private SCMRatisServer ratisServer;
+
+ public Builder setRatisServer(final SCMRatisServer scmRatisServer) {
+ this.ratisServer = scmRatisServer;
+ return this;
+ }
+
+ public Builder setSequenceIdTable(
+ final Table<String, Long> sequenceIdTable) {
+ table = sequenceIdTable;
+ return this;
+ }
+
+ public Builder setDBTransactionBuffer(DBTransactionBuffer trxBuffer) {
+ buffer = trxBuffer;
+ return this;
+ }
+
+ public StateManager build() {
+ Preconditions.checkNotNull(table);
+ Preconditions.checkNotNull(buffer);
+ Preconditions.checkNotNull(ratisServer);
+
+ final StateManager impl = new StateManagerRatisImpl(table, buffer);
+ final SCMHAInvocationHandler invocationHandler
+ = new SCMHAInvocationHandler(SEQUENCE_ID, impl, ratisServer);
+
+ return (StateManager) Proxy.newProxyInstance(
+ SCMHAInvocationHandler.class.getClassLoader(),
+ new Class<?>[]{StateManager.class},
+ invocationHandler);
+ }
+ }
+ }
+
+ /**
+ * non-Ratis based StateMachine, db operations directly go to RocksDB.
+ */
+ static final class StateManagerNonRatisImpl implements StateManager {
+ private final Table<String, Long> sequenceIdTable;
Review comment:
StateManagerNonRatisImpl -> StateManagerImpl
##########
File path: hadoop-hdds/server-scm/src/main/java/org/apache/hadoop/hdds/scm/ha/SequenceIdGen.java
##########
@@ -0,0 +1,284 @@
+/*
+ * 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
+ * <p>
+ * <p>http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * <p>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.hadoop.hdds.scm.ha;
+
+import com.google.common.base.Preconditions;
+import org.apache.hadoop.hdds.conf.ConfigurationSource;
+import org.apache.hadoop.hdds.scm.metadata.Replicate;
+import org.apache.hadoop.hdds.utils.db.Table;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.IOException;
+import java.lang.reflect.Proxy;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
+
+import static org.apache.hadoop.hdds.protocol.proto.SCMRatisProtocol.RequestType.SEQUENCE_ID;
+import static org.apache.hadoop.hdds.scm.ScmConfigKeys.OZONE_SCM_SEQUENCE_ID_BATCH_SIZE;
+import static org.apache.hadoop.hdds.scm.ScmConfigKeys.OZONE_SCM_SEQUENCE_ID_BATCH_SIZE_DEFAULT;
+import static org.apache.hadoop.ozone.OzoneConsts.SEQUENCE_ID_KEY;
+
+/**
+ * After SCM starts, set lastId = 0, nextId = lastId + 1.
+ * The first getNextId() call triggers SCM to load lastId from rocksDB,
+ * and allocate a new batch.
+ *
+ * In order to maintain monotonicity, for Ratis based SequenceIdGen,
+ * when becoming leader, SCM invalidates un-exhausted id batch by setting
+ * nextId = lastId + 1, so that a new leader will reload lastId from
+ * rocksDB and allocate a new batch when receiving its first getNextId() call.
+ */
+public class SequenceIdGen {
+ private static final Logger LOG =
+ LoggerFactory.getLogger(SequenceIdGen.class);
+ private static final long INVALID_SEQUENCE_ID = 0;
+
+ private long lastId = INVALID_SEQUENCE_ID;
+ private long nextId = lastId + 1;
+
+ private final Lock lock;
+ private final long batchSize;
+ private final StateManager stateManager;
+
+ /**
+ * @param conf : conf
+ * @param scmhaManager : null if non-Ratis based
+ * @param sequenceIdTable : sequenceIdTable
+ */
+ public SequenceIdGen(ConfigurationSource conf, SCMHAManager scmhaManager,
+ Table<String, Long> sequenceIdTable) {
+ this.lock = new ReentrantLock();
+ this.batchSize = conf.getInt(OZONE_SCM_SEQUENCE_ID_BATCH_SIZE,
+ OZONE_SCM_SEQUENCE_ID_BATCH_SIZE_DEFAULT);
+
+ if (SCMHAUtils.isSCMHAEnabled(conf)) {
+ this.stateManager = new StateManagerRatisImpl.Builder()
+ .setRatisServer(scmhaManager.getRatisServer())
+ .setDBTransactionBuffer(scmhaManager.getDBTransactionBuffer())
+ .setSequenceIdTable(sequenceIdTable)
+ .build();
+ } else {
+ this.stateManager = new StateManagerNonRatisImpl(sequenceIdTable);
+ }
+ }
+
+ /**
+ * @return next distributed sequence id.
+ */
+ public long getNextId() {
+ lock.lock();
+ try {
+ if (nextId <= lastId) {
+ return nextId++;
+ }
+
+ Preconditions.checkArgument(nextId == lastId + 1);
+ while (true) {
+ Long prevLastId = lastId;
+ nextId = prevLastId + 1;
+ lastId += batchSize;
+
+ if (stateManager.allocateBatch(prevLastId, lastId)) {
+ LOG.info("Allocate a batch, change lastId from {} to {}.",
+ prevLastId, lastId);
+ break;
+ }
+
+ // reload lastId from RocksDB.
+ lastId = stateManager.getLastId();
+ }
+
+ Preconditions.checkArgument(nextId <= lastId);
+ return nextId++;
+
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Invalidate any un-exhausted batch, next getNextId() call will
+ * allocate a new batch.
+ */
+ public void invalidateBatch() {
+ lock.lock();
+ try {
+ nextId = lastId + 1;
+ } finally {
+ lock.unlock();
+ }
+ }
+
+ /**
+ * Maintain SequenceIdTable in RocksDB.
+ */
+ interface StateManager {
+ /**
+ * Compare And Swap lastId saved in db from expectedLastId to newLastId.
+ * If based on Ratis, it will submit a raft client request.
+ *
+ * @param expectedLastId : the expected lastId saved in db
+ * @param newLastId : the new lastId to save in db
+ * @return : result of the C.A.S.
+ */
+ @Replicate
+ Boolean allocateBatch(Long expectedLastId, Long newLastId);
+
+ /**
+ * @return lastId saved in db
+ */
+ Long getLastId();
+ }
+
+ /**
+ * Ratis based StateMachine, db operations are queued in
+ * DBTransactionBuffer until a snapshot is taken.
+ */
+ static final class StateManagerRatisImpl implements StateManager {
+ private final Table<String, Long> sequenceIdTable;
+ private final DBTransactionBuffer transactionBuffer;
+ private volatile Long lastId;
+
+ private StateManagerRatisImpl(Table<String, Long> sequenceIdTable,
+ DBTransactionBuffer trxBuffer) {
+ this.sequenceIdTable = sequenceIdTable;
+ this.transactionBuffer = trxBuffer;
+
+ try {
+ lastId = this.sequenceIdTable.get(SEQUENCE_ID_KEY);
+ } catch (IOException ioe) {
+ throw new RuntimeException("Failed to get lastId from db", ioe);
+ }
+ if (lastId == null) {
+ lastId = INVALID_SEQUENCE_ID;
+ }
+ LOG.info("Init Ratis based SequenceIdGen, lastId is {}.", lastId);
Review comment:
The log message needs to be changed accordingly.
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