io.druid.query.IntervalChunkingQueryRunner.java Source code

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Here is the source code for io.druid.query.IntervalChunkingQueryRunner.java

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/*
 * Druid - a distributed column store.
 * Copyright 2012 - 2015 Metamarkets Group Inc.
 *
 * Licensed 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 io.druid.query;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.Lists;
import com.metamx.common.guava.FunctionalIterable;
import com.metamx.common.guava.Sequence;
import com.metamx.common.guava.Sequences;
import com.metamx.emitter.service.ServiceEmitter;
import com.metamx.emitter.service.ServiceMetricEvent;
import io.druid.granularity.PeriodGranularity;
import io.druid.query.spec.MultipleIntervalSegmentSpec;
import org.joda.time.Interval;
import org.joda.time.Period;

import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ExecutorService;

/**
 */
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 Query<T> query, final Map<String, Object> responseContext) {
        final Period chunkPeriod = getChunkPeriod(query);
        if (chunkPeriod.toStandardDuration().getMillis() == 0) {
            return baseRunner.run(query, responseContext);
        }

        List<Interval> chunkIntervals = Lists.newArrayList(FunctionalIterable.create(query.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(query, 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,
                                        new Function<Query<T>, ServiceMetricEvent.Builder>() {
                                            @Override
                                            public ServiceMetricEvent.Builder apply(Query<T> input) {
                                                return toolChest.makeMetricBuilder(input);
                                            }
                                        }, baseRunner, "query/intervalChunk/time",
                                        ImmutableMap.of("chunkInterval", singleInterval.toString()))
                                                .withWaitMeasuredFromNow()),
                                executor, queryWatcher)
                                        .run(query.withQuerySegmentSpec(
                                                new MultipleIntervalSegmentSpec(Arrays.asList(singleInterval))),
                                                responseContext);
                    }
                })));
    }

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

        List<Interval> intervals = Lists.newArrayList();
        Iterator<Long> timestamps = new PeriodGranularity(period, null, null)
                .iterable(interval.getStartMillis(), interval.getEndMillis()).iterator();

        long start = Math.max(timestamps.next(), interval.getStartMillis());
        while (timestamps.hasNext()) {
            long end = timestamps.next();
            intervals.add(new Interval(start, end));
            start = end;
        }

        if (start < interval.getEndMillis()) {
            intervals.add(new Interval(start, interval.getEndMillis()));
        }

        return intervals;
    }

    private Period getChunkPeriod(Query<T> query) {
        String p = query.getContextValue(QueryContextKeys.CHUNK_PERIOD, "P0D");
        return Period.parse(p);
    }
}