/*
* 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.flink.runtime.state.memory;
import org.apache.flink.api.common.JobID;
import org.apache.flink.api.common.typeutils.TypeSerializer;
import org.apache.flink.runtime.execution.Environment;
import org.apache.flink.runtime.query.TaskKvStateRegistry;
import org.apache.flink.runtime.state.AbstractKeyedStateBackend;
import org.apache.flink.runtime.state.AbstractStateBackend;
import org.apache.flink.runtime.state.CheckpointStreamFactory;
import org.apache.flink.runtime.state.DefaultOperatorStateBackend;
import org.apache.flink.runtime.state.KeyGroupRange;
import org.apache.flink.runtime.state.OperatorStateBackend;
import org.apache.flink.runtime.state.heap.HeapKeyedStateBackend;
import java.io.IOException;
/**
* A {@link AbstractStateBackend} that stores all its data and checkpoints in memory and has no
* capabilities to spill to disk. Checkpoints are serialized and the serialized data is
* transferred
*/
public class MemoryStateBackend extends AbstractStateBackend {
private static final long serialVersionUID = 4109305377809414635L;
/** The default maximal size that the snapshotted memory state may have (5 MiBytes) */
private static final int DEFAULT_MAX_STATE_SIZE = 5 * 1024 * 1024;
/** The maximal size that the snapshotted memory state may have */
private final int maxStateSize;
/** Switch to chose between synchronous and asynchronous snapshots */
private final boolean asynchronousSnapshots;
/**
* Creates a new memory state backend that accepts states whose serialized forms are
* up to the default state size (5 MB).
*/
public MemoryStateBackend() {
this(DEFAULT_MAX_STATE_SIZE);
}
/**
* Creates a new memory state backend that accepts states whose serialized forms are
* up to the given number of bytes.
*
* @param maxStateSize The maximal size of the serialized state
*/
public MemoryStateBackend(int maxStateSize) {
this(maxStateSize, false);
}
/**
* Creates a new memory state backend that accepts states whose serialized forms are
* up to the default state size (5 MB).
*
* @param asynchronousSnapshots Switch to enable asynchronous snapshots.
*/
public MemoryStateBackend(boolean asynchronousSnapshots) {
this(DEFAULT_MAX_STATE_SIZE, asynchronousSnapshots);
}
/**
* Creates a new memory state backend that accepts states whose serialized forms are
* up to the given number of bytes.
*
* @param maxStateSize The maximal size of the serialized state
* @param asynchronousSnapshots Switch to enable asynchronous snapshots.
*/
public MemoryStateBackend(int maxStateSize, boolean asynchronousSnapshots) {
this.maxStateSize = maxStateSize;
this.asynchronousSnapshots = asynchronousSnapshots;
}
@Override
public OperatorStateBackend createOperatorStateBackend(
Environment env,
String operatorIdentifier) throws Exception {
return new DefaultOperatorStateBackend(
env.getUserClassLoader(),
env.getExecutionConfig(),
asynchronousSnapshots);
}
@Override
public String toString() {
return "MemoryStateBackend (data in heap memory / checkpoints to JobManager)";
}
@Override
public CheckpointStreamFactory createStreamFactory(
JobID jobId, String operatorIdentifier) throws IOException {
return new MemCheckpointStreamFactory(maxStateSize);
}
@Override
public CheckpointStreamFactory createSavepointStreamFactory(
JobID jobId,
String operatorIdentifier,
String targetLocation) throws IOException {
return new MemCheckpointStreamFactory(maxStateSize);
}
@Override
public <K> AbstractKeyedStateBackend<K> createKeyedStateBackend(
Environment env, JobID jobID,
String operatorIdentifier,
TypeSerializer<K> keySerializer,
int numberOfKeyGroups,
KeyGroupRange keyGroupRange,
TaskKvStateRegistry kvStateRegistry) {
return new HeapKeyedStateBackend<>(
kvStateRegistry,
keySerializer,
env.getUserClassLoader(),
numberOfKeyGroups,
keyGroupRange,
asynchronousSnapshots,
env.getExecutionConfig());
}
}