org.apache.druid.query.IntervalChunkingQueryRunner.java Source code

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Here is the source code for org.apache.druid.query.IntervalChunkingQueryRunner.java

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/*
 * 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.query;

import com.google.common.base.Function;
import com.google.common.collect.Lists;
import org.apache.druid.java.util.common.DateTimes;
import org.apache.druid.java.util.common.granularity.PeriodGranularity;
import org.apache.druid.java.util.common.guava.FunctionalIterable;
import org.apache.druid.java.util.common.guava.Sequence;
import org.apache.druid.java.util.common.guava.Sequences;
import org.apache.druid.java.util.emitter.service.ServiceEmitter;
import org.apache.druid.query.context.ResponseContext;
import org.apache.druid.query.spec.MultipleIntervalSegmentSpec;
import org.joda.time.DateTime;
import org.joda.time.Interval;
import org.joda.time.Period;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.concurrent.ExecutorService;

/**
 * This class is deprecated and will removed in the future.
 * See https://github.com/apache/incubator-druid/pull/4004#issuecomment-284171911 for details about deprecation.
 */
@Deprecated
public class IntervalChunkingQueryRunner<T> implements QueryRunner<T> {
    private final QueryRunner<T> baseRunner;

    private final QueryToolChest<T, Query<T>> toolChest;
    private final ExecutorService executor;
    private final QueryWatcher queryWatcher;
    private final ServiceEmitter emitter;

    public IntervalChunkingQueryRunner(QueryRunner<T> baseRunner, QueryToolChest<T, Query<T>> toolChest,
            ExecutorService executor, QueryWatcher queryWatcher, ServiceEmitter emitter) {
        this.baseRunner = baseRunner;
        this.toolChest = toolChest;
        this.executor = executor;
        this.queryWatcher = queryWatcher;
        this.emitter = emitter;
    }

    @Override
    public Sequence<T> run(final QueryPlus<T> queryPlus, final ResponseContext responseContext) {
        final Period chunkPeriod = getChunkPeriod(queryPlus.getQuery());

        // Check for non-empty chunkPeriod, avoiding toStandardDuration since that cannot handle periods like P1M.
        if (DateTimes.EPOCH.plus(chunkPeriod).getMillis() == DateTimes.EPOCH.getMillis()) {
            return baseRunner.run(queryPlus, responseContext);
        }

        List<Interval> chunkIntervals = Lists
                .newArrayList(FunctionalIterable.create(queryPlus.getQuery().getIntervals())
                        .transformCat(new Function<Interval, Iterable<Interval>>() {
                            @Override
                            public Iterable<Interval> apply(Interval input) {
                                return splitInterval(input, chunkPeriod);
                            }
                        }));

        if (chunkIntervals.size() <= 1) {
            return baseRunner.run(queryPlus, responseContext);
        }

        return Sequences.concat(Lists.newArrayList(
                FunctionalIterable.create(chunkIntervals).transform(new Function<Interval, Sequence<T>>() {
                    @Override
                    public Sequence<T> apply(Interval singleInterval) {
                        return new AsyncQueryRunner<T>(
                                //Note: it is assumed that toolChest.mergeResults(..) gives a query runner that is
                                //not lazy i.e. it does most of its work on call to run() method
                                toolChest.mergeResults(new MetricsEmittingQueryRunner<T>(emitter, toolChest,
                                        baseRunner, QueryMetrics::reportIntervalChunkTime,
                                        queryMetrics -> queryMetrics.chunkInterval(singleInterval))
                                                .withWaitMeasuredFromNow()),
                                executor, queryWatcher)
                                        .run(queryPlus.withQuerySegmentSpec(new MultipleIntervalSegmentSpec(
                                                Collections.singletonList(singleInterval))), responseContext);
                    }
                })));
    }

    private static Iterable<Interval> splitInterval(Interval interval, Period period) {
        if (interval.getEndMillis() == interval.getStartMillis()) {
            return Collections.singletonList(interval);
        }

        List<Interval> intervals = new ArrayList<>();
        Iterator<Interval> timestamps = new PeriodGranularity(period, null, null).getIterable(interval).iterator();

        DateTime start = DateTimes.max(timestamps.next().getStart(), interval.getStart());
        while (timestamps.hasNext()) {
            DateTime end = timestamps.next().getStart();
            intervals.add(new Interval(start, end));
            start = end;
        }

        if (start.compareTo(interval.getEnd()) < 0) {
            intervals.add(new Interval(start, interval.getEnd()));
        }

        return intervals;
    }

    private Period getChunkPeriod(Query<T> query) {
        final String p = QueryContexts.getChunkPeriod(query);
        return Period.parse(p);
    }
}