org.apache.flink.runtime.checkpoint.StateAssignmentOperation Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one
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* 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,
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* limitations under the License.
*/
package org.apache.flink.runtime.checkpoint;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.runtime.executiongraph.Execution;
import org.apache.flink.runtime.executiongraph.ExecutionJobVertex;
import org.apache.flink.runtime.jobgraph.JobVertexID;
import org.apache.flink.runtime.jobgraph.OperatorID;
import org.apache.flink.runtime.jobgraph.OperatorInstanceID;
import org.apache.flink.runtime.state.KeyGroupRange;
import org.apache.flink.runtime.state.KeyGroupRangeAssignment;
import org.apache.flink.runtime.state.KeyGroupsStateHandle;
import org.apache.flink.runtime.state.KeyedStateHandle;
import org.apache.flink.runtime.state.OperatorStateHandle;
import org.apache.flink.util.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import static org.apache.flink.util.Preconditions.checkNotNull;
import static org.apache.flink.util.Preconditions.checkState;
/**
* This class encapsulates the operation of assigning restored state when restoring from a checkpoint.
*/
public class StateAssignmentOperation {
private static final Logger LOG = LoggerFactory.getLogger(StateAssignmentOperation.class);
private final Map tasks;
private final Map operatorStates;
private final boolean allowNonRestoredState;
public StateAssignmentOperation(
Map tasks,
Map operatorStates,
boolean allowNonRestoredState) {
this.tasks = Preconditions.checkNotNull(tasks);
this.operatorStates = Preconditions.checkNotNull(operatorStates);
this.allowNonRestoredState = allowNonRestoredState;
}
public boolean assignStates() throws Exception {
Map localOperators = new HashMap<>(operatorStates);
Map localTasks = this.tasks;
checkStateMappingCompleteness(allowNonRestoredState, operatorStates, tasks);
for (Map.Entry task : localTasks.entrySet()) {
final ExecutionJobVertex executionJobVertex = task.getValue();
// find the states of all operators belonging to this task
List operatorIDs = executionJobVertex.getOperatorIDs();
List altOperatorIDs = executionJobVertex.getUserDefinedOperatorIDs();
List operatorStates = new ArrayList<>();
boolean statelessTask = true;
for (int x = 0; x < operatorIDs.size(); x++) {
OperatorID operatorID = altOperatorIDs.get(x) == null
? operatorIDs.get(x)
: altOperatorIDs.get(x);
OperatorState operatorState = localOperators.remove(operatorID);
if (operatorState == null) {
operatorState = new OperatorState(
operatorID,
executionJobVertex.getParallelism(),
executionJobVertex.getMaxParallelism());
} else {
statelessTask = false;
}
operatorStates.add(operatorState);
}
if (statelessTask) { // skip tasks where no operator has any state
continue;
}
assignAttemptState(task.getValue(), operatorStates);
}
return true;
}
private void assignAttemptState(ExecutionJobVertex executionJobVertex, List operatorStates) {
List operatorIDs = executionJobVertex.getOperatorIDs();
//1. first compute the new parallelism
checkParallelismPreconditions(operatorStates, executionJobVertex);
int newParallelism = executionJobVertex.getParallelism();
List keyGroupPartitions = createKeyGroupPartitions(
executionJobVertex.getMaxParallelism(),
newParallelism);
/**
* Redistribute ManagedOperatorStates and RawOperatorStates from old parallelism to new parallelism.
*
* The old ManagedOperatorStates with old parallelism 3:
*
* parallelism0 parallelism1 parallelism2
* op0 states0,0 state0,1 state0,2
* op1
* op2 states2,0 state2,1 state1,2
* op3 states3,0 state3,1 state3,2
*
* The new ManagedOperatorStates with new parallelism 4:
*
* parallelism0 parallelism1 parallelism2 parallelism3
* op0 state0,0 state0,1 state0,2 state0,3
* op1
* op2 state2,0 state2,1 state2,2 state2,3
* op3 state3,0 state3,1 state3,2 state3,3
*/
Map> newManagedOperatorStates = new HashMap<>();
Map> newRawOperatorStates = new HashMap<>();
reDistributePartitionableStates(
operatorStates,
newParallelism,
operatorIDs,
newManagedOperatorStates,
newRawOperatorStates);
Map> newManagedKeyedState = new HashMap<>();
Map> newRawKeyedState = new HashMap<>();
reDistributeKeyedStates(
operatorStates,
newParallelism,
operatorIDs,
keyGroupPartitions,
newManagedKeyedState,
newRawKeyedState);
/**
* An executionJobVertex's all state handles needed to restore are something like a matrix
*
* parallelism0 parallelism1 parallelism2 parallelism3
* op0 sh(0,0) sh(0,1) sh(0,2) sh(0,3)
* op1 sh(1,0) sh(1,1) sh(1,2) sh(1,3)
* op2 sh(2,0) sh(2,1) sh(2,2) sh(2,3)
* op3 sh(3,0) sh(3,1) sh(3,2) sh(3,3)
*
*/
assignTaskStateToExecutionJobVertices(
executionJobVertex,
newManagedOperatorStates,
newRawOperatorStates,
newManagedKeyedState,
newRawKeyedState,
newParallelism);
}
private void assignTaskStateToExecutionJobVertices(
ExecutionJobVertex executionJobVertex,
Map> subManagedOperatorState,
Map> subRawOperatorState,
Map> subManagedKeyedState,
Map> subRawKeyedState,
int newParallelism) {
List operatorIDs = executionJobVertex.getOperatorIDs();
for (int subTaskIndex = 0; subTaskIndex < newParallelism; subTaskIndex++) {
Execution currentExecutionAttempt = executionJobVertex.getTaskVertices()[subTaskIndex]
.getCurrentExecutionAttempt();
TaskStateSnapshot taskState = new TaskStateSnapshot();
boolean statelessTask = true;
for (OperatorID operatorID : operatorIDs) {
OperatorInstanceID instanceID = OperatorInstanceID.of(subTaskIndex, operatorID);
OperatorSubtaskState operatorSubtaskState = operatorSubtaskStateFrom(
instanceID,
subManagedOperatorState,
subRawOperatorState,
subManagedKeyedState,
subRawKeyedState);
if (operatorSubtaskState.hasState()) {
statelessTask = false;
}
taskState.putSubtaskStateByOperatorID(operatorID, operatorSubtaskState);
}
if (!statelessTask) {
currentExecutionAttempt.setInitialState(taskState);
}
}
}
public static OperatorSubtaskState operatorSubtaskStateFrom(
OperatorInstanceID instanceID,
Map> subManagedOperatorState,
Map> subRawOperatorState,
Map> subManagedKeyedState,
Map> subRawKeyedState) {
if (!subManagedOperatorState.containsKey(instanceID) &&
!subRawOperatorState.containsKey(instanceID) &&
!subManagedKeyedState.containsKey(instanceID) &&
!subRawKeyedState.containsKey(instanceID)) {
return new OperatorSubtaskState();
}
if (!subManagedKeyedState.containsKey(instanceID)) {
checkState(!subRawKeyedState.containsKey(instanceID));
}
return new OperatorSubtaskState(
subManagedOperatorState.getOrDefault(instanceID, Collections.emptyList()),
subRawOperatorState.getOrDefault(instanceID, Collections.emptyList()),
subManagedKeyedState.getOrDefault(instanceID, Collections.emptyList()),
subRawKeyedState.getOrDefault(instanceID, Collections.emptyList()));
}
private static boolean isHeadOperator(int opIdx, List operatorIDs) {
return opIdx == operatorIDs.size() - 1;
}
public void checkParallelismPreconditions(List operatorStates, ExecutionJobVertex executionJobVertex) {
for (OperatorState operatorState : operatorStates) {
checkParallelismPreconditions(operatorState, executionJobVertex);
}
}
private void reDistributeKeyedStates(
List oldOperatorStates,
int newParallelism,
List newOperatorIDs,
List newKeyGroupPartitions,
Map> newManagedKeyedState,
Map> newRawKeyedState) {
//TODO: rewrite this method to only use OperatorID
checkState(newOperatorIDs.size() == oldOperatorStates.size(),
"This method still depends on the order of the new and old operators");
for (int operatorIndex = 0; operatorIndex < newOperatorIDs.size(); operatorIndex++) {
OperatorState operatorState = oldOperatorStates.get(operatorIndex);
int oldParallelism = operatorState.getParallelism();
for (int subTaskIndex = 0; subTaskIndex < newParallelism; subTaskIndex++) {
OperatorInstanceID instanceID = OperatorInstanceID.of(subTaskIndex, newOperatorIDs.get(operatorIndex));
if (isHeadOperator(operatorIndex, newOperatorIDs)) {
Tuple2, Collection> subKeyedStates = reAssignSubKeyedStates(
operatorState,
newKeyGroupPartitions,
subTaskIndex,
newParallelism,
oldParallelism);
newManagedKeyedState
.computeIfAbsent(instanceID, key -> new ArrayList<>())
.addAll(subKeyedStates.f0);
newRawKeyedState
.computeIfAbsent(instanceID, key -> new ArrayList<>())
.addAll(subKeyedStates.f1);
}
}
}
}
// TODO rewrite based on operator id
private Tuple2, Collection> reAssignSubKeyedStates(
OperatorState operatorState,
List keyGroupPartitions,
int subTaskIndex,
int newParallelism,
int oldParallelism) {
Collection subManagedKeyedState;
Collection subRawKeyedState;
if (newParallelism == oldParallelism) {
if (operatorState.getState(subTaskIndex) != null) {
subManagedKeyedState = operatorState.getState(subTaskIndex).getManagedKeyedState();
subRawKeyedState = operatorState.getState(subTaskIndex).getRawKeyedState();
} else {
subManagedKeyedState = Collections.emptyList();
subRawKeyedState = Collections.emptyList();
}
} else {
subManagedKeyedState = getManagedKeyedStateHandles(operatorState, keyGroupPartitions.get(subTaskIndex));
subRawKeyedState = getRawKeyedStateHandles(operatorState, keyGroupPartitions.get(subTaskIndex));
}
if (subManagedKeyedState.isEmpty() && subRawKeyedState.isEmpty()) {
return new Tuple2<>(Collections.emptyList(), Collections.emptyList());
} else {
return new Tuple2<>(subManagedKeyedState, subRawKeyedState);
}
}
private void reDistributePartitionableStates(
List oldOperatorStates,
int newParallelism,
List newOperatorIDs,
Map> newManagedOperatorStates,
Map> newRawOperatorStates) {
//TODO: rewrite this method to only use OperatorID
checkState(newOperatorIDs.size() == oldOperatorStates.size(),
"This method still depends on the order of the new and old operators");
//collect the old partitionable state
List> oldManagedOperatorStates = new ArrayList<>();
List> oldRawOperatorStates = new ArrayList<>();
collectPartionableStates(oldOperatorStates, oldManagedOperatorStates, oldRawOperatorStates);
//redistribute
OperatorStateRepartitioner opStateRepartitioner = RoundRobinOperatorStateRepartitioner.INSTANCE;
for (int operatorIndex = 0; operatorIndex < oldOperatorStates.size(); operatorIndex++) {
OperatorID operatorID = newOperatorIDs.get(operatorIndex);
int oldParallelism = oldOperatorStates.get(operatorIndex).getParallelism();
newManagedOperatorStates.putAll(applyRepartitioner(
operatorID,
opStateRepartitioner,
oldManagedOperatorStates.get(operatorIndex),
oldParallelism,
newParallelism));
newRawOperatorStates.putAll(applyRepartitioner(
operatorID,
opStateRepartitioner,
oldRawOperatorStates.get(operatorIndex),
oldParallelism,
newParallelism));
}
}
private void collectPartionableStates(
List operatorStates,
List> managedOperatorStates,
List> rawOperatorStates) {
for (OperatorState operatorState : operatorStates) {
List managedOperatorState = null;
List rawOperatorState = null;
for (int i = 0; i < operatorState.getParallelism(); i++) {
OperatorSubtaskState operatorSubtaskState = operatorState.getState(i);
if (operatorSubtaskState != null) {
if (managedOperatorState == null) {
managedOperatorState = new ArrayList<>();
}
managedOperatorState.addAll(operatorSubtaskState.getManagedOperatorState());
if (rawOperatorState == null) {
rawOperatorState = new ArrayList<>();
}
rawOperatorState.addAll(operatorSubtaskState.getRawOperatorState());
}
}
managedOperatorStates.add(managedOperatorState);
rawOperatorStates.add(rawOperatorState);
}
}
/**
* Collect {@link KeyGroupsStateHandle managedKeyedStateHandles} which have intersection with given
* {@link KeyGroupRange} from {@link TaskState operatorState}
*
* @param operatorState all state handles of a operator
* @param subtaskKeyGroupRange the KeyGroupRange of a subtask
* @return all managedKeyedStateHandles which have intersection with given KeyGroupRange
*/
public static List getManagedKeyedStateHandles(
OperatorState operatorState,
KeyGroupRange subtaskKeyGroupRange) {
List subtaskKeyedStateHandles = new ArrayList<>();
for (int i = 0; i < operatorState.getParallelism(); i++) {
if (operatorState.getState(i) != null) {
Collection keyedStateHandles = operatorState.getState(i).getManagedKeyedState();
extractIntersectingState(
keyedStateHandles,
subtaskKeyGroupRange,
subtaskKeyedStateHandles);
}
}
return subtaskKeyedStateHandles;
}
/**
* Collect {@link KeyGroupsStateHandle rawKeyedStateHandles} which have intersection with given
* {@link KeyGroupRange} from {@link TaskState operatorState}
*
* @param operatorState all state handles of a operator
* @param subtaskKeyGroupRange the KeyGroupRange of a subtask
* @return all rawKeyedStateHandles which have intersection with given KeyGroupRange
*/
public static List getRawKeyedStateHandles(
OperatorState operatorState,
KeyGroupRange subtaskKeyGroupRange) {
List extractedKeyedStateHandles = new ArrayList<>();
for (int i = 0; i < operatorState.getParallelism(); i++) {
if (operatorState.getState(i) != null) {
Collection rawKeyedState = operatorState.getState(i).getRawKeyedState();
extractIntersectingState(
rawKeyedState,
subtaskKeyGroupRange,
extractedKeyedStateHandles);
}
}
return extractedKeyedStateHandles;
}
/**
* Extracts certain key group ranges from the given state handles and adds them to the collector.
*/
private static void extractIntersectingState(
Collection originalSubtaskStateHandles,
KeyGroupRange rangeToExtract,
List extractedStateCollector) {
for (KeyedStateHandle keyedStateHandle : originalSubtaskStateHandles) {
if (keyedStateHandle != null) {
KeyedStateHandle intersectedKeyedStateHandle = keyedStateHandle.getIntersection(rangeToExtract);
if (intersectedKeyedStateHandle != null) {
extractedStateCollector.add(intersectedKeyedStateHandle);
}
}
}
}
/**
* Groups the available set of key groups into key group partitions. A key group partition is
* the set of key groups which is assigned to the same task. Each set of the returned list
* constitutes a key group partition.
*
* IMPORTANT: The assignment of key groups to partitions has to be in sync with the
* KeyGroupStreamPartitioner.
*
* @param numberKeyGroups Number of available key groups (indexed from 0 to numberKeyGroups - 1)
* @param parallelism Parallelism to generate the key group partitioning for
* @return List of key group partitions
*/
public static List createKeyGroupPartitions(int numberKeyGroups, int parallelism) {
Preconditions.checkArgument(numberKeyGroups >= parallelism);
List result = new ArrayList<>(parallelism);
for (int i = 0; i < parallelism; ++i) {
result.add(KeyGroupRangeAssignment.computeKeyGroupRangeForOperatorIndex(numberKeyGroups, parallelism, i));
}
return result;
}
/**
* Verifies conditions in regards to parallelism and maxParallelism that must be met when restoring state.
*
* @param operatorState state to restore
* @param executionJobVertex task for which the state should be restored
*/
private static void checkParallelismPreconditions(OperatorState operatorState, ExecutionJobVertex executionJobVertex) {
//----------------------------------------max parallelism preconditions-------------------------------------
if (operatorState.getMaxParallelism() < executionJobVertex.getParallelism()) {
throw new IllegalStateException("The state for task " + executionJobVertex.getJobVertexId() +
" can not be restored. The maximum parallelism (" + operatorState.getMaxParallelism() +
") of the restored state is lower than the configured parallelism (" + executionJobVertex.getParallelism() +
"). Please reduce the parallelism of the task to be lower or equal to the maximum parallelism."
);
}
// check that the number of key groups have not changed or if we need to override it to satisfy the restored state
if (operatorState.getMaxParallelism() != executionJobVertex.getMaxParallelism()) {
if (!executionJobVertex.isMaxParallelismConfigured()) {
// if the max parallelism was not explicitly specified by the user, we derive it from the state
LOG.debug("Overriding maximum parallelism for JobVertex {} from {} to {}",
executionJobVertex.getJobVertexId(), executionJobVertex.getMaxParallelism(), operatorState.getMaxParallelism());
executionJobVertex.setMaxParallelism(operatorState.getMaxParallelism());
} else {
// if the max parallelism was explicitly specified, we complain on mismatch
throw new IllegalStateException("The maximum parallelism (" +
operatorState.getMaxParallelism() + ") with which the latest " +
"checkpoint of the execution job vertex " + executionJobVertex +
" has been taken and the current maximum parallelism (" +
executionJobVertex.getMaxParallelism() + ") changed. This " +
"is currently not supported.");
}
}
}
/**
* Verifies that all operator states can be mapped to an execution job vertex.
*
* @param allowNonRestoredState if false an exception will be thrown if a state could not be mapped
* @param operatorStates operator states to map
* @param tasks task to map to
*/
private static void checkStateMappingCompleteness(
boolean allowNonRestoredState,
Map operatorStates,
Map tasks) {
Set allOperatorIDs = new HashSet<>();
for (ExecutionJobVertex executionJobVertex : tasks.values()) {
allOperatorIDs.addAll(executionJobVertex.getOperatorIDs());
}
for (Map.Entry operatorGroupStateEntry : operatorStates.entrySet()) {
OperatorState operatorState = operatorGroupStateEntry.getValue();
//----------------------------------------find operator for state---------------------------------------------
if (!allOperatorIDs.contains(operatorGroupStateEntry.getKey())) {
if (allowNonRestoredState) {
LOG.info("Skipped checkpoint state for operator {}.", operatorState.getOperatorID());
} else {
throw new IllegalStateException("There is no operator for the state " + operatorState.getOperatorID());
}
}
}
}
public static Map> applyRepartitioner(
OperatorID operatorID,
OperatorStateRepartitioner opStateRepartitioner,
List chainOpParallelStates,
int oldParallelism,
int newParallelism) {
Map> result = new HashMap<>();
List> states = applyRepartitioner(
opStateRepartitioner,
chainOpParallelStates,
oldParallelism,
newParallelism);
for (int subtaskIndex = 0; subtaskIndex < states.size(); subtaskIndex++) {
checkNotNull(states.get(subtaskIndex) != null, "states.get(subtaskIndex) is null");
result
.computeIfAbsent(OperatorInstanceID.of(subtaskIndex, operatorID), key -> new ArrayList<>())
.addAll(states.get(subtaskIndex));
}
return result;
}
/**
* Repartitions the given operator state using the given {@link OperatorStateRepartitioner} with respect to the new
* parallelism.
*
* @param opStateRepartitioner partitioner to use
* @param chainOpParallelStates state to repartition
* @param oldParallelism parallelism with which the state is currently partitioned
* @param newParallelism parallelism with which the state should be partitioned
* @return repartitioned state
*/
// TODO rewrite based on operator id
public static List> applyRepartitioner(
OperatorStateRepartitioner opStateRepartitioner,
List chainOpParallelStates,
int oldParallelism,
int newParallelism) {
if (chainOpParallelStates == null) {
return Collections.emptyList();
}
//We only redistribute if the parallelism of the operator changed from previous executions
if (newParallelism != oldParallelism) {
return opStateRepartitioner.repartitionState(
chainOpParallelStates,
newParallelism);
} else {
List> repackStream = new ArrayList<>(newParallelism);
for (OperatorStateHandle operatorStateHandle : chainOpParallelStates) {
if (operatorStateHandle != null) {
Map partitionOffsets =
operatorStateHandle.getStateNameToPartitionOffsets();
for (OperatorStateHandle.StateMetaInfo metaInfo : partitionOffsets.values()) {
// if we find any broadcast state, we cannot take the shortcut and need to go through repartitioning
if (OperatorStateHandle.Mode.BROADCAST.equals(metaInfo.getDistributionMode())) {
return opStateRepartitioner.repartitionState(
chainOpParallelStates,
newParallelism);
}
}
repackStream.add(Collections.singletonList(operatorStateHandle));
}
}
return repackStream;
}
}
/**
* Determine the subset of {@link KeyGroupsStateHandle KeyGroupsStateHandles} with correct
* key group index for the given subtask {@link KeyGroupRange}.
*
*
This is publicly visible to be used in tests.
*/
public static List getKeyedStateHandles(
Collection keyedStateHandles,
KeyGroupRange subtaskKeyGroupRange) {
List subtaskKeyedStateHandles = new ArrayList<>();
for (KeyedStateHandle keyedStateHandle : keyedStateHandles) {
KeyedStateHandle intersectedKeyedStateHandle = keyedStateHandle.getIntersection(subtaskKeyGroupRange);
if (intersectedKeyedStateHandle != null) {
subtaskKeyedStateHandles.add(intersectedKeyedStateHandle);
}
}
return subtaskKeyedStateHandles;
}
}