cryptoe commented on code in PR #13205:
URL: https://github.com/apache/druid/pull/13205#discussion_r1021360261
##########
processing/src/main/java/org/apache/druid/frame/key/RowKeyReader.java:
##########
@@ -130,6 +130,28 @@ public boolean hasMultipleValues(final RowKey key, final
int fieldNumber)
}
}
+ /**
+ * Trims the key reader to a particular fieldCount. Used to read keys
trimmed by {@link #trim(RowKey, int)}.
+ */
+ public RowKeyReader trimmedKeyReader(int trimmedFieldCount)
Review Comment:
We can easily UT this I think
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/ClusterStatisticsMergeMode.java:
##########
@@ -0,0 +1,41 @@
+/*
+ * 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.druid.msq.exec;
+
+/**
+ * Mode which dictates how {@link WorkerSketchFetcher} gets sketches from
workers.
+ */
+public enum ClusterStatisticsMergeMode
+{
+ /**
+ * Fetches sketch in sequential order based on time. Slower due to overhead,
but more accurate.
+ */
+ SEQUENTIAL,
+
+ /**
+ * Fetch all sketches from the worker at once. Faster to generate
partitions, but less accurate.
+ */
+ PARALLEL,
+
+ /**
+ * Tries to decide between sequential and parallel modes based on the number
of workers and size of the input
+ */
+ AUTO
Review Comment:
Curious to understand how auto works here. Maybe a comment here would be
useful.
##########
integration-tests-ex/cases/src/test/java/org/apache/druid/testsEx/msq/ITMultiStageQuery.java:
##########
@@ -122,4 +126,144 @@ public void testMsqIngestionAndQuerying() throws Exception
msqHelper.testQueriesFromFile(QUERY_FILE, datasource);
}
+
+ @Test
+ public void testMsqIngestionParallelMerging() throws Exception
+ {
+ String datasource = "dst";
+
+ // Clear up the datasource from the previous runs
+ coordinatorClient.unloadSegmentsForDataSource(datasource);
+
+ String queryLocal =
+ StringUtils.format(
+ "INSERT INTO %s\n"
+ + "SELECT\n"
+ + " TIME_PARSE(\"timestamp\") AS __time,\n"
+ + " isRobot,\n"
+ + " diffUrl,\n"
+ + " added,\n"
+ + " countryIsoCode,\n"
+ + " regionName,\n"
+ + " channel,\n"
+ + " flags,\n"
+ + " delta,\n"
+ + " isUnpatrolled,\n"
+ + " isNew,\n"
+ + " deltaBucket,\n"
+ + " isMinor,\n"
+ + " isAnonymous,\n"
+ + " deleted,\n"
+ + " cityName,\n"
+ + " metroCode,\n"
+ + " namespace,\n"
+ + " comment,\n"
+ + " page,\n"
+ + " commentLength,\n"
+ + " countryName,\n"
+ + " user,\n"
+ + " regionIsoCode\n"
+ + "FROM TABLE(\n"
+ + " EXTERN(\n"
+ + "
'{\"type\":\"local\",\"files\":[\"/resources/data/batch_index/json/wikipedia_index_data1.json\"]}',\n"
+ + " '{\"type\":\"json\"}',\n"
+ + "
'[{\"type\":\"string\",\"name\":\"timestamp\"},{\"type\":\"string\",\"name\":\"isRobot\"},{\"type\":\"string\",\"name\":\"diffUrl\"},{\"type\":\"long\",\"name\":\"added\"},{\"type\":\"string\",\"name\":\"countryIsoCode\"},{\"type\":\"string\",\"name\":\"regionName\"},{\"type\":\"string\",\"name\":\"channel\"},{\"type\":\"string\",\"name\":\"flags\"},{\"type\":\"long\",\"name\":\"delta\"},{\"type\":\"string\",\"name\":\"isUnpatrolled\"},{\"type\":\"string\",\"name\":\"isNew\"},{\"type\":\"double\",\"name\":\"deltaBucket\"},{\"type\":\"string\",\"name\":\"isMinor\"},{\"type\":\"string\",\"name\":\"isAnonymous\"},{\"type\":\"long\",\"name\":\"deleted\"},{\"type\":\"string\",\"name\":\"cityName\"},{\"type\":\"long\",\"name\":\"metroCode\"},{\"type\":\"string\",\"name\":\"namespace\"},{\"type\":\"string\",\"name\":\"comment\"},{\"type\":\"string\",\"name\":\"page\"},{\"type\":\"long\",\"name\":\"commentLength\"},{\"type\":\"string\",\"name\":\"countryName\"},{\"type\":
\"string\",\"name\":\"user\"},{\"type\":\"string\",\"name\":\"regionIsoCode\"}]'\n"
+ + " )\n"
+ + ")\n"
+ + "PARTITIONED BY DAY\n"
+ + "CLUSTERED BY \"__time\"",
+ datasource
+ );
+
+ ImmutableMap<String, Object> context = ImmutableMap.of(
+ MultiStageQueryContext.CTX_CLUSTER_STATISTICS_MERGE_MODE,
+ ClusterStatisticsMergeMode.PARALLEL
Review Comment:
Do we need tests for auto mode ?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/kernel/controller/ControllerStageTracker.java:
##########
@@ -227,19 +221,28 @@ WorkerInputs getWorkerInputs()
return workerInputs;
}
+ /**
+ * Returns the merged key statistics.
+ */
+ @Nullable
+ public WorkerAggregatedKeyStatistics getAggregatedKeyStatistics()
+ {
+ return aggregatedKeyStatistics;
+ }
+
/**
* Adds result key statistics for a particular worker number. If statistics
have already been added for this worker,
* then this call ignores the new ones and does nothing.
*
* @param workerNumber the worker
- * @param snapshot worker statistics
+ * @param aggregatedKeyStatistics aggregated key statistics
*/
- ControllerStagePhase addResultKeyStatisticsForWorker(
+ ControllerStagePhase addAggregatedStatisticsForWorker(
final int workerNumber,
- final ClusterByStatisticsSnapshot snapshot
+ final WorkerAggregatedKeyStatistics aggregatedKeyStatistics
Review Comment:
PartialStageKeyStats? seems more apt no ?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/ControllerImpl.java:
##########
@@ -590,7 +599,34 @@ public void updateStatus(int stageNumber, int
workerNumber, Object keyStatistics
);
}
- queryKernel.addResultKeyStatisticsForStageAndWorker(stageId,
workerNumber, keyStatistics);
+ queryKernel.addResultStatisticsReportForStageAndWorker(stageId,
workerNumber, aggregatedKeyStatistics);
Review Comment:
addAggregateKeyStatisticsForStageAndWorker ?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/kernel/controller/ControllerStageTracker.java:
##########
@@ -252,14 +255,17 @@ ControllerStagePhase addResultKeyStatisticsForWorker(
}
try {
- if (workersWithResultKeyStatistics.add(workerNumber)) {
- resultKeyStatisticsCollector.addAll(snapshot);
+ if (workersWithFinishedReport.add(workerNumber)) {
+ aggregatedKeyStatistics.addAll(aggregatedKeyStatistics);
- if (workersWithResultKeyStatistics.size() == workerCount) {
- generateResultPartitionsAndBoundaries();
+ if (workersWithFinishedReport.size() == workerCount) {
+ // All workers have sent the report.
+ // Transition to MERGING_STATISTICS state to queue fetch clustering
statistics from workers.
+ transitionTo(ControllerStagePhase.MERGING_STATISTICS);
- // Phase can become FAILED after
generateResultPartitionsAndBoundaries, if there were too many partitions.
- if (phase != ControllerStagePhase.FAILED) {
+ if (!stageDef.doesShuffle()) {
Review Comment:
Lets throw an exception if stage mustgatherResultStats is false.
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/WorkerClient.java:
##########
@@ -38,6 +40,24 @@ public interface WorkerClient extends AutoCloseable
*/
ListenableFuture<Void> postWorkOrder(String workerId, WorkOrder workOrder);
+ /**
+ * Fetches the {@link ClusterByStatisticsSnapshot} from a worker. This is
intended to be used by the
+ * {@link WorkerSketchFetcher}.
+ */
+ ClusterByStatisticsSnapshot fetchClusterByStatisticsSnapshot(String
workerTaskId, String queryId, int stageNumber)
+ throws ExecutionException, InterruptedException;
+
+ /**
+ * Fetches a {@link ClusterByStatisticsSnapshot} which contains only the
sketch of the specified timeChunk.
+ * This is intended to be used by the {@link WorkerSketchFetcher}.
Review Comment:
Lets document the mode as well
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/ControllerImpl.java:
##########
@@ -590,7 +599,34 @@ public void updateStatus(int stageNumber, int
workerNumber, Object keyStatistics
);
}
- queryKernel.addResultKeyStatisticsForStageAndWorker(stageId,
workerNumber, keyStatistics);
+ queryKernel.addResultStatisticsReportForStageAndWorker(stageId,
workerNumber, aggregatedKeyStatistics);
+
+ if
(queryKernel.getStagePhase(stageId).equals(ControllerStagePhase.MERGING_STATISTICS))
{
+ List<String> workerTaskIds = workerTaskLauncher.getTaskList();
+ WorkerAggregatedKeyStatistics mergedKeyStatistics =
queryKernel.getAggregatedKeyStatistics(stageId);
+
+ // Queue the sketch fetching task into the worker sketch fetcher.
+ CompletableFuture<Either<Long, ClusterByPartitions>>
clusterByPartitionsCompletableFuture =
+ workerSketchFetcher.submitFetcherTask(
+ mergedKeyStatistics,
+ workerTaskIds,
+ stageDef
+ );
+
+ // Add the listener to handle completion.
+
clusterByPartitionsCompletableFuture.whenComplete((clusterByPartitionsEither,
throwable) -> {
+ if (throwable != null) {
+ queryKernel.failStageForReason(stageId,
UnknownFault.forException(throwable));
+ } else if (clusterByPartitionsEither.isError()) {
+ queryKernel.failStageForReason(stageId, new
TooManyPartitionsFault(stageDef.getMaxPartitionCount()));
+ } else {
+ queryKernel.setClusterByPartitionBoundaries(stageId,
clusterByPartitionsEither.valueOrThrow());
Review Comment:
All these operations are required to be added to kernalManipulationQueue so
that they are linearized.
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/ExceptionWrappingWorkerClient.java:
##########
@@ -55,6 +57,24 @@ public ListenableFuture<Void> postWorkOrder(String
workerTaskId, WorkOrder workO
return wrap(workerTaskId, client, c -> c.postWorkOrder(workerTaskId,
workOrder));
}
+ @Override
+ public ClusterByStatisticsSnapshot fetchClusterByStatisticsSnapshot(String
workerTaskId, String queryId, int stageNumber)
+ throws ExecutionException, InterruptedException
+ {
+ return client.fetchClusterByStatisticsSnapshot(workerTaskId, queryId,
stageNumber);
+ }
+
+ @Override
+ public ClusterByStatisticsSnapshot fetchSingletonStatisticsSnapshot(
Review Comment:
fetchClusterByStatisticsSnapshotForTimeChunk ?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/WorkerSketchFetcher.java:
##########
@@ -0,0 +1,253 @@
+/*
+ * 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.druid.msq.exec;
+
+import org.apache.druid.frame.key.ClusterBy;
+import org.apache.druid.frame.key.ClusterByPartition;
+import org.apache.druid.frame.key.ClusterByPartitions;
+import org.apache.druid.java.util.common.Either;
+import org.apache.druid.msq.kernel.StageDefinition;
+import org.apache.druid.msq.statistics.ClusterByStatisticsCollector;
+import org.apache.druid.msq.statistics.ClusterByStatisticsSnapshot;
+import org.apache.druid.msq.statistics.WorkerAggregatedKeyStatistics;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Queues up fetching sketches from workers and progressively generates
partitions boundaries.
+ */
+public class WorkerSketchFetcher
+{
+ private static final int DEFAULT_THREAD_COUNT = 10;
+ private static final long BYTES_THRESHOLD = 1_000_000_000L;
+ private static final long WORKER_THRESHOLD = 100;
+
+ private final ClusterStatisticsMergeMode clusterStatisticsMergeMode;
+ private final WorkerClient workerClient;
+ private final ExecutorService executorService;
+
+ public WorkerSketchFetcher(WorkerClient workerClient,
ClusterStatisticsMergeMode clusterStatisticsMergeMode)
+ {
+ this.workerClient = workerClient;
+ this.clusterStatisticsMergeMode = clusterStatisticsMergeMode;
+ this.executorService = Executors.newFixedThreadPool(DEFAULT_THREAD_COUNT);
+ }
+
+ /**
+ * Submits a request to fetch and generate partitions for the given worker
statistics and returns a future for it. It
+ * decides based on the statistics if it should fetch sketches one by one or
together.
+ */
+ public CompletableFuture<Either<Long, ClusterByPartitions>>
submitFetcherTask(
+ WorkerAggregatedKeyStatistics aggregatedKeyStatistics,
+ List<String> workerTaskIds,
+ StageDefinition stageDefinition
+ )
+ {
+ ClusterBy clusterBy = stageDefinition.getClusterBy();
+
+ switch (clusterStatisticsMergeMode) {
+ case SEQUENTIAL:
+ return sequentialTimeChunkMerging(aggregatedKeyStatistics,
stageDefinition, workerTaskIds);
+ case PARALLEL:
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ case AUTO:
+ if (clusterBy.getBucketByCount() == 0) {
Review Comment:
Is this an exception?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/WorkerSketchFetcher.java:
##########
@@ -0,0 +1,253 @@
+/*
+ * 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.druid.msq.exec;
+
+import org.apache.druid.frame.key.ClusterBy;
+import org.apache.druid.frame.key.ClusterByPartition;
+import org.apache.druid.frame.key.ClusterByPartitions;
+import org.apache.druid.java.util.common.Either;
+import org.apache.druid.msq.kernel.StageDefinition;
+import org.apache.druid.msq.statistics.ClusterByStatisticsCollector;
+import org.apache.druid.msq.statistics.ClusterByStatisticsSnapshot;
+import org.apache.druid.msq.statistics.WorkerAggregatedKeyStatistics;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Queues up fetching sketches from workers and progressively generates
partitions boundaries.
+ */
+public class WorkerSketchFetcher
+{
+ private static final int DEFAULT_THREAD_COUNT = 10;
+ private static final long BYTES_THRESHOLD = 1_000_000_000L;
+ private static final long WORKER_THRESHOLD = 100;
+
+ private final ClusterStatisticsMergeMode clusterStatisticsMergeMode;
+ private final WorkerClient workerClient;
+ private final ExecutorService executorService;
+
+ public WorkerSketchFetcher(WorkerClient workerClient,
ClusterStatisticsMergeMode clusterStatisticsMergeMode)
+ {
+ this.workerClient = workerClient;
+ this.clusterStatisticsMergeMode = clusterStatisticsMergeMode;
+ this.executorService = Executors.newFixedThreadPool(DEFAULT_THREAD_COUNT);
+ }
+
+ /**
+ * Submits a request to fetch and generate partitions for the given worker
statistics and returns a future for it. It
+ * decides based on the statistics if it should fetch sketches one by one or
together.
+ */
+ public CompletableFuture<Either<Long, ClusterByPartitions>>
submitFetcherTask(
+ WorkerAggregatedKeyStatistics aggregatedKeyStatistics,
+ List<String> workerTaskIds,
+ StageDefinition stageDefinition
+ )
+ {
+ ClusterBy clusterBy = stageDefinition.getClusterBy();
+
+ switch (clusterStatisticsMergeMode) {
+ case SEQUENTIAL:
+ return sequentialTimeChunkMerging(aggregatedKeyStatistics,
stageDefinition, workerTaskIds);
+ case PARALLEL:
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ case AUTO:
+ if (clusterBy.getBucketByCount() == 0) {
+ // If there is no time cluserting, there is no scope for sequential
merge
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ } else if (stageDefinition.getMaxWorkerCount() > WORKER_THRESHOLD ||
aggregatedKeyStatistics.getBytesRetained() > BYTES_THRESHOLD) {
+ return sequentialTimeChunkMerging(aggregatedKeyStatistics,
stageDefinition, workerTaskIds);
+ } else {
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ }
+ default:
+ throw new IllegalStateException("No fetching strategy found for mode:
" + clusterStatisticsMergeMode);
+ }
+ }
+
+ /**
+ * Fetches the full {@link ClusterByStatisticsCollector} from all workers
and generates partition boundaries from them.
+ * This is faster than fetching them timechunk by timechunk but the
collector will be downsampled till it can fit
+ * on the controller, resulting in less accurate partition boundries.
+ */
+ private CompletableFuture<Either<Long, ClusterByPartitions>>
inMemoryFullSketchMerging(
+ StageDefinition stageDefinition,
+ List<String> workerTaskIds
+ )
+ {
+ CompletableFuture<Either<Long, ClusterByPartitions>> partitionFuture = new
CompletableFuture<>();
+
+ final ClusterByStatisticsCollector mergedStatisticsCollector =
stageDefinition.createResultKeyStatisticsCollector();
+ final int workerCount = workerTaskIds.size();
+ final Set<Integer> finishedWorkers = new HashSet<>();
+
+ for (int i = 0; i < workerCount; i++) {
+ final int workerNo = i;
+ executorService.submit(() -> {
+ try {
+ ClusterByStatisticsSnapshot clusterByStatisticsSnapshot =
workerClient.fetchClusterByStatisticsSnapshot(
+ workerTaskIds.get(workerNo),
+ stageDefinition.getId().getQueryId(),
+ stageDefinition.getStageNumber()
+ );
+
+ // If the future already failed for some reason, stop the task.
+ if (partitionFuture.isDone()) {
+ return;
+ }
+
+ synchronized (mergedStatisticsCollector) {
+ mergedStatisticsCollector.addAll(clusterByStatisticsSnapshot);
+ finishedWorkers.add(workerNo);
+
+ if (finishedWorkers.size() == workerCount) {
+
partitionFuture.complete(stageDefinition.generatePartitionsForShuffle(mergedStatisticsCollector));
+ }
+ }
+ }
+ catch (Exception e) {
+ partitionFuture.completeExceptionally(e);
+ }
+ });
+ }
+ return partitionFuture;
+ }
+
+ /**
+ * Fetches cluster statistics from all workers and generates partition
boundaries from them one time chunk at a time.
+ * This takes longer due to the overhead of fetching sketches, however, this
prevents any loss in accuracy from
+ * downsampling on the controller.
+ */
+ private CompletableFuture<Either<Long, ClusterByPartitions>>
sequentialTimeChunkMerging(
+ WorkerAggregatedKeyStatistics aggregatedKeyStatistics,
+ StageDefinition stageDefinition,
+ List<String> workerTaskIds
+ )
+ {
+ SequentialFetchStage sequentialFetchStage = new SequentialFetchStage(
+ stageDefinition,
+ workerTaskIds,
+
aggregatedKeyStatistics.getTimeSegmentVsWorkerIdMap().entrySet().iterator()
+ );
+ sequentialFetchStage.submitFetchingTasksForNextTimeChunk();
+ return sequentialFetchStage.getPartitionFuture();
+ }
+
+ private class SequentialFetchStage
+ {
+ private final StageDefinition stageDefinition;
+ private final List<String> workerTaskIds;
+ private final Iterator<Map.Entry<Long, Set<Integer>>>
timeSegmentVsWorkerIdIterator;
+ private final CompletableFuture<Either<Long, ClusterByPartitions>>
partitionFuture;
+ private final List<ClusterByPartition> finalPartitionBoundries;
+
+ public SequentialFetchStage(
+ StageDefinition stageDefinition,
+ List<String> workerTaskIds,
+ Iterator<Map.Entry<Long, Set<Integer>>> timeSegmentVsWorkerIdIterator
+ )
+ {
+ this.finalPartitionBoundries = new ArrayList<>();
+ this.stageDefinition = stageDefinition;
+ this.workerTaskIds = workerTaskIds;
+ this.timeSegmentVsWorkerIdIterator = timeSegmentVsWorkerIdIterator;
+ this.partitionFuture = new CompletableFuture<>();
+ }
+
+ public void submitFetchingTasksForNextTimeChunk()
+ {
+ if (!timeSegmentVsWorkerIdIterator.hasNext()) {
+ partitionFuture.complete(Either.value(new
ClusterByPartitions(finalPartitionBoundries)));
+ } else {
+ Map.Entry<Long, Set<Integer>> entry =
timeSegmentVsWorkerIdIterator.next();
+ Long timeChunk = entry.getKey();
+ Set<Integer> workerIdsWithTimeChunk = entry.getValue();
+ ClusterByStatisticsCollector mergedStatisticsCollector =
stageDefinition.createResultKeyStatisticsCollector();
+ Set<Integer> finishedWorkers = new HashSet<>();
+
+ for (int workerNo : workerIdsWithTimeChunk) {
+ executorService.submit(() -> {
+ try {
+ ClusterByStatisticsSnapshot singletonStatisticsSnapshot =
+ workerClient.fetchSingletonStatisticsSnapshot(
+ workerTaskIds.get(workerNo),
+ stageDefinition.getId().getQueryId(),
+ stageDefinition.getStageNumber(),
+ timeChunk
+ );
+ // If the future already failed for some reason, stop the task.
+ if (partitionFuture.isDone()) {
Review Comment:
can this be stale?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/WorkerImpl.java:
##########
@@ -526,6 +533,30 @@ public void postFinish()
kernelManipulationQueue.add(KernelHolder::setDone);
}
+ @Override
+ public ClusterByStatisticsSnapshot fetchStatisticsSnapshot(StageId stageId)
+ throws ExecutionException, InterruptedException
+ {
+ CompletableFuture<ClusterByStatisticsSnapshot> future = new
CompletableFuture<>();
+ kernelManipulationQueue.add(kernelHolder -> {
+
future.complete(kernelHolder.stageKernelMap.get(stageId).getResultKeyStatisticsSnapshot());
+ });
+ return future.get();
+ }
+
+ @Override
+ public ClusterByStatisticsSnapshot fetchSingletonStatisticsSnapshot(StageId
stageId, long timeChunk)
+ throws ExecutionException, InterruptedException
+ {
+ CompletableFuture<ClusterByStatisticsSnapshot> future = new
CompletableFuture<>();
+ kernelManipulationQueue.add(kernelHolder -> {
+ ClusterByStatisticsSnapshot snapshot =
kernelHolder.stageKernelMap.get(stageId).getResultKeyStatisticsSnapshot();
+ ClusterByStatisticsSnapshot singletonSnapshot =
snapshot.getSingletonSnapshot(timeChunk);
+ future.complete(singletonSnapshot);
+ });
+ return future.get();
Review Comment:
Extract the stage, keyStats map outside the kernel, and make it thread-safe?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/WorkerSketchFetcher.java:
##########
@@ -0,0 +1,253 @@
+/*
+ * 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.druid.msq.exec;
+
+import org.apache.druid.frame.key.ClusterBy;
+import org.apache.druid.frame.key.ClusterByPartition;
+import org.apache.druid.frame.key.ClusterByPartitions;
+import org.apache.druid.java.util.common.Either;
+import org.apache.druid.msq.kernel.StageDefinition;
+import org.apache.druid.msq.statistics.ClusterByStatisticsCollector;
+import org.apache.druid.msq.statistics.ClusterByStatisticsSnapshot;
+import org.apache.druid.msq.statistics.WorkerAggregatedKeyStatistics;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Queues up fetching sketches from workers and progressively generates
partitions boundaries.
+ */
+public class WorkerSketchFetcher
+{
+ private static final int DEFAULT_THREAD_COUNT = 10;
Review Comment:
good catch. Yeah, we need to limit the number of parallel threads here. Lets
start with 4 ?
##########
integration-tests-ex/cases/src/test/java/org/apache/druid/testsEx/msq/ITMultiStageQuery.java:
##########
@@ -122,4 +126,144 @@ public void testMsqIngestionAndQuerying() throws Exception
msqHelper.testQueriesFromFile(QUERY_FILE, datasource);
}
+
+ @Test
+ public void testMsqIngestionParallelMerging() throws Exception
Review Comment:
Let's create a new test class for these tests no ?
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/Worker.java:
##########
@@ -67,6 +69,17 @@
*/
void postWorkOrder(WorkOrder workOrder);
+ /**
+ * Returns the statistics snapshot for the given stageId
+ */
+ ClusterByStatisticsSnapshot fetchStatisticsSnapshot(StageId stageId) throws
ExecutionException, InterruptedException;
+
+ /**
+ * Returns the statistics snapshot for the given stageId which contains only
the sketch for the specified timeChunk
Review Comment:
Please also document which mode is this API getting used in.
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/kernel/controller/ControllerStageTracker.java:
##########
@@ -252,14 +255,17 @@ ControllerStagePhase addResultKeyStatisticsForWorker(
}
try {
- if (workersWithResultKeyStatistics.add(workerNumber)) {
- resultKeyStatisticsCollector.addAll(snapshot);
+ if (workersWithFinishedReport.add(workerNumber)) {
Review Comment:
Lets rename accordingly when `PartialStageKeyStats` is used
##########
extensions-core/multi-stage-query/src/main/java/org/apache/druid/msq/exec/WorkerSketchFetcher.java:
##########
@@ -0,0 +1,253 @@
+/*
+ * 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.druid.msq.exec;
+
+import org.apache.druid.frame.key.ClusterBy;
+import org.apache.druid.frame.key.ClusterByPartition;
+import org.apache.druid.frame.key.ClusterByPartitions;
+import org.apache.druid.java.util.common.Either;
+import org.apache.druid.msq.kernel.StageDefinition;
+import org.apache.druid.msq.statistics.ClusterByStatisticsCollector;
+import org.apache.druid.msq.statistics.ClusterByStatisticsSnapshot;
+import org.apache.druid.msq.statistics.WorkerAggregatedKeyStatistics;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+
+/**
+ * Queues up fetching sketches from workers and progressively generates
partitions boundaries.
+ */
+public class WorkerSketchFetcher
+{
+ private static final int DEFAULT_THREAD_COUNT = 10;
+ private static final long BYTES_THRESHOLD = 1_000_000_000L;
+ private static final long WORKER_THRESHOLD = 100;
+
+ private final ClusterStatisticsMergeMode clusterStatisticsMergeMode;
+ private final WorkerClient workerClient;
+ private final ExecutorService executorService;
+
+ public WorkerSketchFetcher(WorkerClient workerClient,
ClusterStatisticsMergeMode clusterStatisticsMergeMode)
+ {
+ this.workerClient = workerClient;
+ this.clusterStatisticsMergeMode = clusterStatisticsMergeMode;
+ this.executorService = Executors.newFixedThreadPool(DEFAULT_THREAD_COUNT);
+ }
+
+ /**
+ * Submits a request to fetch and generate partitions for the given worker
statistics and returns a future for it. It
+ * decides based on the statistics if it should fetch sketches one by one or
together.
+ */
+ public CompletableFuture<Either<Long, ClusterByPartitions>>
submitFetcherTask(
+ WorkerAggregatedKeyStatistics aggregatedKeyStatistics,
+ List<String> workerTaskIds,
+ StageDefinition stageDefinition
+ )
+ {
+ ClusterBy clusterBy = stageDefinition.getClusterBy();
+
+ switch (clusterStatisticsMergeMode) {
+ case SEQUENTIAL:
+ return sequentialTimeChunkMerging(aggregatedKeyStatistics,
stageDefinition, workerTaskIds);
+ case PARALLEL:
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ case AUTO:
+ if (clusterBy.getBucketByCount() == 0) {
+ // If there is no time cluserting, there is no scope for sequential
merge
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ } else if (stageDefinition.getMaxWorkerCount() > WORKER_THRESHOLD ||
aggregatedKeyStatistics.getBytesRetained() > BYTES_THRESHOLD) {
+ return sequentialTimeChunkMerging(aggregatedKeyStatistics,
stageDefinition, workerTaskIds);
+ } else {
+ return inMemoryFullSketchMerging(stageDefinition, workerTaskIds);
+ }
+ default:
+ throw new IllegalStateException("No fetching strategy found for mode:
" + clusterStatisticsMergeMode);
+ }
+ }
+
+ /**
+ * Fetches the full {@link ClusterByStatisticsCollector} from all workers
and generates partition boundaries from them.
+ * This is faster than fetching them timechunk by timechunk but the
collector will be downsampled till it can fit
+ * on the controller, resulting in less accurate partition boundries.
+ */
+ private CompletableFuture<Either<Long, ClusterByPartitions>>
inMemoryFullSketchMerging(
+ StageDefinition stageDefinition,
+ List<String> workerTaskIds
+ )
+ {
+ CompletableFuture<Either<Long, ClusterByPartitions>> partitionFuture = new
CompletableFuture<>();
+
+ final ClusterByStatisticsCollector mergedStatisticsCollector =
stageDefinition.createResultKeyStatisticsCollector();
+ final int workerCount = workerTaskIds.size();
+ final Set<Integer> finishedWorkers = new HashSet<>();
+
+ for (int i = 0; i < workerCount; i++) {
Review Comment:
IntStream might help
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