com.hazelcast.jet.sql.impl.connector.map.MapIndexScanP Maven / Gradle / Ivy
/*
* Copyright 2021 Hazelcast Inc.
*
* Licensed under the Hazelcast Community License (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://hazelcast.com/hazelcast-community-license
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.hazelcast.jet.sql.impl.connector.map;
import com.hazelcast.cluster.Address;
import com.hazelcast.core.HazelcastInstance;
import com.hazelcast.core.HazelcastInstanceNotActiveException;
import com.hazelcast.core.MemberLeftException;
import com.hazelcast.internal.iteration.IndexIterationPointer;
import com.hazelcast.internal.partition.InternalPartitionService;
import com.hazelcast.internal.serialization.InternalSerializationService;
import com.hazelcast.internal.util.collection.PartitionIdSet;
import com.hazelcast.jet.core.AbstractProcessor;
import com.hazelcast.jet.core.Processor;
import com.hazelcast.jet.core.ProcessorSupplier;
import com.hazelcast.jet.impl.connector.AbstractIndexReader;
import com.hazelcast.jet.sql.impl.ExpressionUtil;
import com.hazelcast.map.impl.operation.MapFetchIndexOperation;
import com.hazelcast.map.impl.operation.MapFetchIndexOperation.MapFetchIndexOperationResult;
import com.hazelcast.map.impl.operation.MapFetchIndexOperation.MissingPartitionException;
import com.hazelcast.map.impl.operation.MapOperationProvider;
import com.hazelcast.map.impl.proxy.MapProxyImpl;
import com.hazelcast.nio.ObjectDataInput;
import com.hazelcast.nio.ObjectDataOutput;
import com.hazelcast.nio.serialization.DataSerializable;
import com.hazelcast.query.impl.QueryableEntry;
import com.hazelcast.query.impl.getters.Extractors;
import com.hazelcast.security.permission.MapPermission;
import com.hazelcast.spi.exception.TargetDisconnectedException;
import com.hazelcast.spi.exception.TargetNotMemberException;
import com.hazelcast.spi.exception.WrongTargetException;
import com.hazelcast.spi.impl.InternalCompletableFuture;
import com.hazelcast.spi.impl.operationservice.Operation;
import com.hazelcast.sql.impl.exec.scan.MapIndexScanMetadata;
import com.hazelcast.sql.impl.exec.scan.MapScanRow;
import com.hazelcast.sql.impl.exec.scan.index.IndexFilter;
import com.hazelcast.sql.impl.expression.ExpressionEvalContext;
import com.hazelcast.sql.impl.row.JetSqlRow;
import javax.annotation.Nonnull;
import java.io.IOException;
import java.security.Permission;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.PrimitiveIterator;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.stream.IntStream;
import static com.hazelcast.jet.impl.util.Util.getNodeEngine;
import static com.hazelcast.query.impl.getters.GetterCache.SIMPLE_GETTER_CACHE_SUPPLIER;
import static com.hazelcast.security.permission.ActionConstants.ACTION_CREATE;
import static com.hazelcast.security.permission.ActionConstants.ACTION_READ;
import static java.util.Collections.emptyList;
import static java.util.Collections.singletonList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.stream.Collectors.toList;
/**
* Implementation of migration-tolerant IMap index scan processor.
*
* The key component of migration-tolerant index scan is so-called 'split'.
* It's the basic unit of execution that is attached to a concrete member
* and there exists a single instance during normal execution.
*
* Scan algorithm initially assumes that all assigned partitions are local.
* Processor sends {@link MapFetchIndexOperation} to the local member
* during normal execution, and to all members which own partitions
* assigned to the processor after migration. After response is received,
* processor saves the new `pointers` to `lastPointers`, emits to
* processor's outbox, and sends another operation with the new pointers.
*
* During partition migration processor will split the partitions in the
* original `split` into disjoint parts, according to the owner, and retry
* with the new owners. If all partitions in a `split` were read, the
* `split` is removed from execution.
*/
final class MapIndexScanP extends AbstractProcessor {
private static final long DELAY_AFTER_MISSING_PARTITION = MILLISECONDS.toNanos(100);
private final MapIndexScanMetadata metadata;
private HazelcastInstance hazelcastInstance;
private ExpressionEvalContext evalContext;
private AbstractIndexReader> reader;
private final ArrayList splits = new ArrayList<>();
private MapScanRow row;
private JetSqlRow pendingItem;
private boolean isIndexSorted;
private MapIndexScanP(@Nonnull MapIndexScanMetadata indexScanMetadata) {
this.metadata = indexScanMetadata;
}
@Override
protected void init(@Nonnull Context context) {
hazelcastInstance = context.hazelcastInstance();
evalContext = ExpressionEvalContext.from(context);
reader = new LocalMapIndexReader(hazelcastInstance, evalContext.getSerializationService(), metadata);
int[] memberPartitions = context.processorPartitions();
splits.add(new Split(
new PartitionIdSet(hazelcastInstance.getPartitionService().getPartitions().size(), memberPartitions),
hazelcastInstance.getCluster().getLocalMember().getAddress(),
filtersToPointers(metadata.getFilter(), metadata.isDescending(), evalContext)
));
row = MapScanRow.create(
metadata.getKeyDescriptor(),
metadata.getValueDescriptor(),
metadata.getFieldPaths(),
metadata.getFieldTypes(),
Extractors.newBuilder(evalContext.getSerializationService())
.setGetterCacheSupplier(SIMPLE_GETTER_CACHE_SUPPLIER)
.build(),
evalContext.getSerializationService()
);
isIndexSorted = metadata.getComparator() != null;
}
private static IndexIterationPointer[] filtersToPointers(
@Nonnull IndexFilter filter,
boolean descending,
ExpressionEvalContext evalContext
) {
return IndexIterationPointer.createFromIndexFilter(filter, descending, evalContext);
}
@Override
public boolean complete() {
return isIndexSorted ? runSortedIndex() : runHashIndex();
}
@Override
public boolean closeIsCooperative() {
return true;
}
private boolean runSortedIndex() {
for (; ; ) {
if (pendingItem != null && !tryEmit(pendingItem)) {
return false;
} else {
pendingItem = null;
}
JetSqlRow extreme = null;
int extremeIndex = -1;
for (int i = 0; i < splits.size(); ++i) {
Split split = splits.get(i);
try {
split.peek();
} catch (MissingPartitionException e) {
splits.addAll(splitOnMigration(split));
splits.remove(i--);
continue;
}
if (split.currentRow == null) {
if (split.done()) {
// No more items to read, remove finished split.
splits.remove(i--);
continue;
}
// waiting for more rows from this split
return false;
}
if (extremeIndex < 0
|| metadata.getComparator().compare(split.currentRow, splits.get(extremeIndex).currentRow) < 0) {
extremeIndex = i;
extreme = split.currentRow;
}
}
if (extremeIndex < 0) {
assert splits.isEmpty();
return true;
}
pendingItem = extreme;
splits.get(extremeIndex).remove();
}
}
private boolean runHashIndex() {
for (; ; ) {
for (int i = 0; i < splits.size(); ++i) {
Split split = splits.get(i);
try {
split.peek();
} catch (MissingPartitionException e) {
splits.addAll(splitOnMigration(split));
splits.remove(i--);
continue;
}
if (split.currentRow == null) {
if (split.done()) {
// No more items to read, remove finished split.
splits.remove(i--);
if (splits.isEmpty()) {
return true;
}
}
} else {
if (tryEmit(split.currentRow)) {
split.remove();
} else {
return false;
}
}
}
}
}
/**
* Perform splitting of a {@link Split} after receiving {@link MissingPartitionException}
* or various cluster state exceptions like {@link MemberLeftException}.
*
* Method gets current partition table and proceeds with following procedure:
*
* It splits the partitions assigned to the split according to the new
* partition owner into disjoint sets, one for each owner.
*
* @param split the split to split
* @return collection of new split units
*/
private List splitOnMigration(Split split) {
IndexIterationPointer[] lastPointers = split.pointers;
InternalPartitionService partitionService = getNodeEngine(hazelcastInstance).getPartitionService();
Map newSplits = new HashMap<>();
PrimitiveIterator.OfInt partitionIterator = split.partitions.intIterator();
while (partitionIterator.hasNext()) {
int partitionId = partitionIterator.nextInt();
// If at least one partition owner is not assigned -- assign current member.
// Later, a WrongTargetException will be thrown
// and it causes this method to be called again.
// Occasionally prediction with current member would be correct.
Address potentialOwner = partitionService.getPartition(partitionId).getOwnerOrNull();
Address owner = potentialOwner == null
? split.owner
: partitionService.getPartition(partitionId).getOwnerOrNull();
newSplits.computeIfAbsent(owner, x -> new Split(
new PartitionIdSet(partitionService.getPartitionCount()), owner, lastPointers)
).partitions.add(partitionId);
}
ArrayList res = new ArrayList<>(newSplits.values());
// if the resulting split is the same as the input split, postpone retrying it
if (res.size() == 1) {
Split newSplit = res.get(0);
if (newSplit.owner.equals(split.owner) && newSplit.partitions.equals(split.partitions)) {
newSplit.postponeUntil(System.nanoTime() + DELAY_AFTER_MISSING_PARTITION);
}
}
return res;
}
/**
* Basic unit of index scan execution bounded to concrete member and partitions set.
* Can be split into smaller splits after migration is detected.
*/
private final class Split {
private final PartitionIdSet partitions;
private final Address owner;
private IndexIterationPointer[] pointers;
private List> currentBatch = emptyList();
private JetSqlRow currentRow;
private int currentBatchPosition;
private CompletableFuture future;
private long postponeUntil = Long.MIN_VALUE;
private Split(PartitionIdSet partitions, Address owner, IndexIterationPointer[] pointers) {
this.partitions = partitions;
this.owner = owner;
this.pointers = pointers;
this.currentBatchPosition = 0;
this.future = null;
}
private void postponeUntil(long postponeUntil) {
this.postponeUntil = postponeUntil;
}
/**
* After this call, {@link #currentRow} will return the next entry to emit.
* They are set to null, if there's no row available
* because we're either done or waiting for more data.
*/
private void peek() {
if (postponeUntil > Long.MIN_VALUE) {
if (System.nanoTime() < postponeUntil) {
return;
} else {
postponeUntil = Long.MIN_VALUE;
}
}
// start a new async call, if we're not done and one isn't in flight
if (future == null && pointers.length > 0) {
future = reader.readBatch(owner, partitions, pointers);
}
// get the next batch from the future, if the current batch is done and one is in flight
if (currentBatch.size() == currentBatchPosition && future != null && future.isDone()) {
MapFetchIndexOperationResult result;
try {
result = reader.toBatchResult(future);
} catch (ExecutionException e) {
// unwrap the MissingPartitionException, and wrap other exceptions as MPE
Throwable t = findTopologyExceptionInCauses(e);
if (t != null) {
throw new MissingPartitionException(t.toString(), e);
}
throw new RuntimeException(e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
currentBatch = reader.toRecordSet(result);
currentBatchPosition = 0;
pointers = result.getPointers();
future = null;
}
// project the next item
while (currentRow == null && currentBatchPosition < currentBatch.size()) {
// Sometimes scan query may not include indexed field.
// So, additional projection is required to ability to merge-sort an output.
currentRow = projectAndFilter(currentBatch.get(currentBatchPosition));
if (currentRow == null) {
currentBatchPosition++;
}
}
}
/**
* Returns a topology exception from the given Throwable or its causes.
* Topology exception are those related to a member leaving the cluster.
* We handle them the same as {@link MissingPartitionException} trigger.
*/
@SuppressWarnings("BooleanExpressionComplexity")
private Throwable findTopologyExceptionInCauses(Throwable t) {
while (t != null) {
if (t instanceof MissingPartitionException
|| t instanceof HazelcastInstanceNotActiveException
|| t instanceof MemberLeftException
|| t instanceof TargetDisconnectedException
|| t instanceof TargetNotMemberException
|| t instanceof WrongTargetException
) {
return t;
}
t = t.getCause();
}
return null;
}
private JetSqlRow projectAndFilter(@Nonnull QueryableEntry entry) {
row.setKeyValue(
entry.getKeyIfPresent(), entry.getKeyDataIfPresent(),
entry.getValueIfPresent(), entry.getValueDataIfPresent()
);
return ExpressionUtil.evaluate(metadata.getRemainingFilter(), metadata.getProjection(), row, evalContext);
}
private void remove() {
currentBatchPosition++;
currentRow = null;
}
private boolean done() {
return currentBatchPosition == currentBatch.size() && pointers.length == 0;
}
@Override
public String toString() {
return "Split{" +
"partitions=" + partitions +
", owner=" + owner +
", hash=" + System.identityHashCode(this) +
'}';
}
}
private static final class LocalMapIndexReader
extends AbstractIndexReader> {
static final int FETCH_SIZE_HINT = 128;
private final HazelcastInstance hazelcastInstance;
private final String indexName;
private LocalMapIndexReader(
@Nonnull HazelcastInstance hzInstance,
@Nonnull InternalSerializationService serializationService,
@Nonnull MapIndexScanMetadata indexScanMetadata
) {
super(indexScanMetadata.getMapName(), MapFetchIndexOperationResult::getEntries);
this.hazelcastInstance = hzInstance;
this.indexName = indexScanMetadata.getIndexName();
this.serializationService = serializationService;
}
@Override
@Nonnull
public InternalCompletableFuture readBatch(
Address address,
PartitionIdSet partitions,
IndexIterationPointer[] pointers
) {
MapProxyImpl mapProxyImpl = (MapProxyImpl) hazelcastInstance.getMap(objectName);
MapOperationProvider operationProvider = mapProxyImpl.getOperationProvider();
Operation op = operationProvider.createFetchIndexOperation(
mapProxyImpl.getName(),
indexName,
pointers,
partitions,
FETCH_SIZE_HINT
);
return mapProxyImpl.getOperationService().invokeOnTarget(mapProxyImpl.getServiceName(), op, address);
}
}
static ProcessorSupplier readMapIndexSupplier(MapIndexScanMetadata indexScanMetadata) {
return new MapIndexScanProcessorSupplier(indexScanMetadata);
}
private static final class MapIndexScanProcessorSupplier implements ProcessorSupplier, DataSerializable {
private MapIndexScanMetadata metadata;
@SuppressWarnings("unused")
private MapIndexScanProcessorSupplier() {
}
private MapIndexScanProcessorSupplier(@Nonnull MapIndexScanMetadata metadata) {
this.metadata = metadata;
}
@Override
@Nonnull
public List get(int count) {
return IntStream.range(0, count)
.mapToObj(i -> new MapIndexScanP(metadata))
.collect(toList());
}
@Override
public List permissions() {
return singletonList(new MapPermission(metadata.getMapName(), ACTION_CREATE, ACTION_READ));
}
@Override
public void writeData(ObjectDataOutput out) throws IOException {
out.writeObject(metadata);
}
@Override
public void readData(ObjectDataInput in) throws IOException {
metadata = in.readObject();
}
}
}