io.druid.segment.IndexMergerV9.java Source code

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/*
 * Licensed to Metamarkets Group Inc. (Metamarkets) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. Metamarkets 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 io.druid.segment;

import com.fasterxml.jackson.databind.ObjectMapper;
import com.google.common.base.Function;
import com.google.common.base.Preconditions;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Ordering;
import com.google.common.collect.Sets;
import com.google.common.io.ByteStreams;
import com.google.common.io.Files;
import com.google.common.primitives.Ints;
import com.google.common.primitives.Longs;
import com.google.inject.Inject;
import io.druid.collections.CombiningIterable;
import io.druid.common.utils.JodaUtils;
import io.druid.io.ZeroCopyByteArrayOutputStream;
import io.druid.java.util.common.IAE;
import io.druid.java.util.common.ISE;
import io.druid.java.util.common.guava.Comparators;
import io.druid.java.util.common.guava.FunctionalIterable;
import io.druid.java.util.common.guava.MergeIterable;
import io.druid.java.util.common.io.Closer;
import io.druid.java.util.common.io.smoosh.FileSmoosher;
import io.druid.java.util.common.io.smoosh.SmooshedWriter;
import io.druid.java.util.common.logger.Logger;
import io.druid.query.aggregation.AggregatorFactory;
import io.druid.segment.column.Column;
import io.druid.segment.column.ColumnCapabilities;
import io.druid.segment.column.ColumnCapabilitiesImpl;
import io.druid.segment.column.ColumnDescriptor;
import io.druid.segment.column.ValueType;
import io.druid.segment.data.CompressedObjectStrategy;
import io.druid.segment.data.CompressionFactory;
import io.druid.segment.data.GenericIndexed;
import io.druid.segment.data.IOPeon;
import io.druid.segment.data.Indexed;
import io.druid.segment.data.TmpFileIOPeon;
import io.druid.segment.incremental.IncrementalIndex;
import io.druid.segment.incremental.IncrementalIndexAdapter;
import io.druid.segment.loading.MMappedQueryableSegmentizerFactory;
import io.druid.segment.serde.ComplexColumnPartSerde;
import io.druid.segment.serde.ComplexMetricSerde;
import io.druid.segment.serde.ComplexMetrics;
import io.druid.segment.serde.DoubleGenericColumnPartSerde;
import io.druid.segment.serde.FloatGenericColumnPartSerde;
import io.druid.segment.serde.LongGenericColumnPartSerde;
import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
import it.unimi.dsi.fastutil.ints.IntIterator;
import it.unimi.dsi.fastutil.ints.IntSortedSet;
import org.apache.commons.io.FileUtils;
import org.joda.time.DateTime;
import org.joda.time.Interval;

import javax.annotation.Nullable;
import java.io.Closeable;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.IntBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Set;

public class IndexMergerV9 implements IndexMerger {
    private static final Logger log = new Logger(IndexMergerV9.class);
    protected final ObjectMapper mapper;
    protected final IndexIO indexIO;

    @Inject
    public IndexMergerV9(ObjectMapper mapper, IndexIO indexIO) {
        this.mapper = Preconditions.checkNotNull(mapper, "null ObjectMapper");
        this.indexIO = Preconditions.checkNotNull(indexIO, "null IndexIO");

    }

    private static void registerDeleteDirectory(Closer closer, final File dir) {
        closer.register(new Closeable() {
            @Override
            public void close() throws IOException {
                FileUtils.deleteDirectory(dir);
            }
        });
    }

    private File makeIndexFiles(final List<IndexableAdapter> adapters, final AggregatorFactory[] metricAggs,
            final File outDir, final ProgressIndicator progress, final List<String> mergedDimensions,
            final List<String> mergedMetrics,
            final Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>> rowMergerFn, final IndexSpec indexSpec)
            throws IOException {
        progress.start();
        progress.progress();

        List<Metadata> metadataList = Lists.transform(adapters, new Function<IndexableAdapter, Metadata>() {
            @Override
            public Metadata apply(IndexableAdapter input) {
                return input.getMetadata();
            }
        });

        Metadata segmentMetadata = null;
        if (metricAggs != null) {
            AggregatorFactory[] combiningMetricAggs = new AggregatorFactory[metricAggs.length];
            for (int i = 0; i < metricAggs.length; i++) {
                combiningMetricAggs[i] = metricAggs[i].getCombiningFactory();
            }
            segmentMetadata = Metadata.merge(metadataList, combiningMetricAggs);
        } else {
            segmentMetadata = Metadata.merge(metadataList, null);
        }

        Closer closer = Closer.create();
        try {
            final FileSmoosher v9Smoosher = new FileSmoosher(outDir);
            final File v9TmpDir = new File(outDir, "v9-tmp");
            FileUtils.forceMkdir(v9TmpDir);
            registerDeleteDirectory(closer, v9TmpDir);
            log.info("Start making v9 index files, outDir:%s", outDir);

            File tmpPeonFilesDir = new File(v9TmpDir, "tmpPeonFiles");
            FileUtils.forceMkdir(tmpPeonFilesDir);
            registerDeleteDirectory(closer, tmpPeonFilesDir);
            final IOPeon ioPeon = new TmpFileIOPeon(tmpPeonFilesDir, false);
            closer.register(ioPeon);
            long startTime = System.currentTimeMillis();
            ByteStreams.write(Ints.toByteArray(IndexIO.V9_VERSION),
                    Files.newOutputStreamSupplier(new File(outDir, "version.bin")));
            log.info("Completed version.bin in %,d millis.", System.currentTimeMillis() - startTime);

            progress.progress();
            startTime = System.currentTimeMillis();
            try (FileOutputStream fos = new FileOutputStream(new File(outDir, "factory.json"))) {
                mapper.writeValue(fos, new MMappedQueryableSegmentizerFactory(indexIO));
            }
            log.info("Completed factory.json in %,d millis", System.currentTimeMillis() - startTime);

            progress.progress();
            final Map<String, ValueType> metricsValueTypes = Maps
                    .newTreeMap(Comparators.<String>naturalNullsFirst());
            final Map<String, String> metricTypeNames = Maps.newTreeMap(Comparators.<String>naturalNullsFirst());
            final List<ColumnCapabilitiesImpl> dimCapabilities = Lists
                    .newArrayListWithCapacity(mergedDimensions.size());
            mergeCapabilities(adapters, mergedDimensions, metricsValueTypes, metricTypeNames, dimCapabilities);

            final DimensionHandler[] handlers = makeDimensionHandlers(mergedDimensions, dimCapabilities);
            final List<DimensionMerger> mergers = new ArrayList<>();
            for (int i = 0; i < mergedDimensions.size(); i++) {
                mergers.add(handlers[i].makeMerger(indexSpec, v9TmpDir, ioPeon, dimCapabilities.get(i), progress));
            }

            /************* Setup Dim Conversions **************/
            progress.progress();
            startTime = System.currentTimeMillis();
            final ArrayList<Map<String, IntBuffer>> dimConversions = Lists
                    .newArrayListWithCapacity(adapters.size());
            final ArrayList<Boolean> dimensionSkipFlag = Lists.newArrayListWithCapacity(mergedDimensions.size());
            final ArrayList<Boolean> convertMissingDimsFlags = Lists
                    .newArrayListWithCapacity(mergedDimensions.size());
            writeDimValueAndSetupDimConversion(adapters, progress, mergedDimensions, mergers);
            log.info("Completed dim conversions in %,d millis.", System.currentTimeMillis() - startTime);

            /************* Walk through data sets, merge them, and write merged columns *************/
            progress.progress();
            final Iterable<Rowboat> theRows = makeRowIterable(adapters, mergedDimensions, mergedMetrics,
                    rowMergerFn, dimCapabilities, handlers, mergers);
            final LongColumnSerializer timeWriter = setupTimeWriter(ioPeon, indexSpec);
            final ArrayList<GenericColumnSerializer> metWriters = setupMetricsWriters(ioPeon, mergedMetrics,
                    metricsValueTypes, metricTypeNames, indexSpec);
            final List<IntBuffer> rowNumConversions = Lists.newArrayListWithCapacity(adapters.size());

            mergeIndexesAndWriteColumns(adapters, progress, theRows, timeWriter, metWriters, rowNumConversions,
                    mergers);

            /************ Create Inverted Indexes and Finalize Build Columns *************/
            final String section = "build inverted index and columns";
            progress.startSection(section);
            makeTimeColumn(v9Smoosher, progress, timeWriter);
            makeMetricsColumns(v9Smoosher, progress, mergedMetrics, metricsValueTypes, metricTypeNames, metWriters);

            for (int i = 0; i < mergedDimensions.size(); i++) {
                DimensionMergerV9 merger = (DimensionMergerV9) mergers.get(i);
                merger.writeIndexes(rowNumConversions, closer);
                if (merger.canSkip()) {
                    continue;
                }
                ColumnDescriptor columnDesc = merger.makeColumnDescriptor();
                makeColumn(v9Smoosher, mergedDimensions.get(i), columnDesc);
            }

            progress.stopSection(section);

            /************* Make index.drd & metadata.drd files **************/
            progress.progress();
            makeIndexBinary(v9Smoosher, adapters, outDir, mergedDimensions, mergedMetrics, progress, indexSpec,
                    mergers);
            makeMetadataBinary(v9Smoosher, progress, segmentMetadata);

            v9Smoosher.close();
            progress.stop();

            return outDir;
        } catch (Throwable t) {
            throw closer.rethrow(t);
        } finally {
            closer.close();
        }
    }

    private void makeMetadataBinary(final FileSmoosher v9Smoosher, final ProgressIndicator progress,
            final Metadata segmentMetadata) throws IOException {
        if (segmentMetadata != null) {
            progress.startSection("make metadata.drd");
            v9Smoosher.add("metadata.drd", ByteBuffer.wrap(mapper.writeValueAsBytes(segmentMetadata)));
            progress.stopSection("make metadata.drd");
        }
    }

    private void makeIndexBinary(final FileSmoosher v9Smoosher, final List<IndexableAdapter> adapters,
            final File outDir, final List<String> mergedDimensions, final List<String> mergedMetrics,
            final ProgressIndicator progress, final IndexSpec indexSpec, final List<DimensionMerger> mergers)
            throws IOException {
        final String section = "make index.drd";
        progress.startSection(section);

        long startTime = System.currentTimeMillis();
        final Set<String> finalDimensions = Sets.newLinkedHashSet();
        final Set<String> finalColumns = Sets.newLinkedHashSet();
        finalColumns.addAll(mergedMetrics);
        for (int i = 0; i < mergedDimensions.size(); ++i) {
            if (mergers.get(i).canSkip()) {
                continue;
            }
            finalColumns.add(mergedDimensions.get(i));
            finalDimensions.add(mergedDimensions.get(i));
        }

        GenericIndexed<String> cols = GenericIndexed.fromIterable(finalColumns, GenericIndexed.STRING_STRATEGY);
        GenericIndexed<String> dims = GenericIndexed.fromIterable(finalDimensions, GenericIndexed.STRING_STRATEGY);

        final String bitmapSerdeFactoryType = mapper.writeValueAsString(indexSpec.getBitmapSerdeFactory());
        final long numBytes = cols.getSerializedSize() + dims.getSerializedSize() + 16
                + serializerUtils.getSerializedStringByteSize(bitmapSerdeFactoryType);

        final SmooshedWriter writer = v9Smoosher.addWithSmooshedWriter("index.drd", numBytes);
        cols.writeToChannel(writer);
        dims.writeToChannel(writer);

        DateTime minTime = new DateTime(JodaUtils.MAX_INSTANT);
        DateTime maxTime = new DateTime(JodaUtils.MIN_INSTANT);

        for (IndexableAdapter index : adapters) {
            minTime = JodaUtils.minDateTime(minTime, index.getDataInterval().getStart());
            maxTime = JodaUtils.maxDateTime(maxTime, index.getDataInterval().getEnd());
        }
        final Interval dataInterval = new Interval(minTime, maxTime);

        serializerUtils.writeLong(writer, dataInterval.getStartMillis());
        serializerUtils.writeLong(writer, dataInterval.getEndMillis());

        serializerUtils.writeString(writer, bitmapSerdeFactoryType);
        writer.close();

        IndexIO.checkFileSize(new File(outDir, "index.drd"));
        log.info("Completed index.drd in %,d millis.", System.currentTimeMillis() - startTime);

        progress.stopSection(section);
    }

    private void makeMetricsColumns(final FileSmoosher v9Smoosher, final ProgressIndicator progress,
            final List<String> mergedMetrics, final Map<String, ValueType> metricsValueTypes,
            final Map<String, String> metricTypeNames, final List<GenericColumnSerializer> metWriters)
            throws IOException {
        final String section = "make metric columns";
        progress.startSection(section);
        long startTime = System.currentTimeMillis();

        for (int i = 0; i < mergedMetrics.size(); ++i) {
            String metric = mergedMetrics.get(i);
            long metricStartTime = System.currentTimeMillis();
            GenericColumnSerializer writer = metWriters.get(i);
            writer.close();

            final ColumnDescriptor.Builder builder = ColumnDescriptor.builder();
            ValueType type = metricsValueTypes.get(metric);
            switch (type) {
            case LONG:
                builder.setValueType(ValueType.LONG);
                builder.addSerde(LongGenericColumnPartSerde.serializerBuilder().withByteOrder(IndexIO.BYTE_ORDER)
                        .withDelegate((LongColumnSerializer) writer).build());
                break;
            case FLOAT:
                builder.setValueType(ValueType.FLOAT);
                builder.addSerde(FloatGenericColumnPartSerde.serializerBuilder().withByteOrder(IndexIO.BYTE_ORDER)
                        .withDelegate((FloatColumnSerializer) writer).build());
                break;
            case DOUBLE:
                builder.setValueType(ValueType.DOUBLE);
                builder.addSerde(DoubleGenericColumnPartSerde.serializerBuilder().withByteOrder(IndexIO.BYTE_ORDER)
                        .withDelegate((DoubleColumnSerializer) writer).build());
                break;
            case COMPLEX:
                final String typeName = metricTypeNames.get(metric);
                builder.setValueType(ValueType.COMPLEX);
                builder.addSerde(ComplexColumnPartSerde.serializerBuilder().withTypeName(typeName)
                        .withDelegate(writer).build());
                break;
            default:
                throw new ISE("Unknown type[%s]", type);
            }
            makeColumn(v9Smoosher, metric, builder.build());
            log.info("Completed metric column[%s] in %,d millis.", metric,
                    System.currentTimeMillis() - metricStartTime);
        }
        log.info("Completed metric columns in %,d millis.", System.currentTimeMillis() - startTime);
        progress.stopSection(section);
    }

    private void makeTimeColumn(final FileSmoosher v9Smoosher, final ProgressIndicator progress,
            final LongColumnSerializer timeWriter) throws IOException {
        final String section = "make time column";
        progress.startSection(section);
        long startTime = System.currentTimeMillis();

        timeWriter.close();

        final ColumnDescriptor serdeficator = ColumnDescriptor.builder().setValueType(ValueType.LONG)
                .addSerde(LongGenericColumnPartSerde.serializerBuilder().withByteOrder(IndexIO.BYTE_ORDER)
                        .withDelegate(timeWriter).build())
                .build();
        makeColumn(v9Smoosher, Column.TIME_COLUMN_NAME, serdeficator);
        log.info("Completed time column in %,d millis.", System.currentTimeMillis() - startTime);
        progress.stopSection(section);
    }

    private void makeColumn(final FileSmoosher v9Smoosher, final String columnName,
            final ColumnDescriptor serdeficator) throws IOException {
        ZeroCopyByteArrayOutputStream specBytes = new ZeroCopyByteArrayOutputStream();
        serializerUtils.writeString(specBytes, mapper.writeValueAsString(serdeficator));
        try (SmooshedWriter channel = v9Smoosher.addWithSmooshedWriter(columnName,
                serdeficator.numBytes() + specBytes.size())) {
            specBytes.writeTo(channel);
            serdeficator.write(channel, v9Smoosher);
        }
    }

    private void mergeIndexesAndWriteColumns(final List<IndexableAdapter> adapters,
            final ProgressIndicator progress, final Iterable<Rowboat> theRows,
            final LongColumnSerializer timeWriter, final ArrayList<GenericColumnSerializer> metWriters,
            final List<IntBuffer> rowNumConversions, final List<DimensionMerger> mergers) throws IOException {
        final String section = "walk through and merge rows";
        progress.startSection(section);
        long startTime = System.currentTimeMillis();

        int rowCount = 0;
        for (IndexableAdapter adapter : adapters) {
            int[] arr = new int[adapter.getNumRows()];
            Arrays.fill(arr, INVALID_ROW);
            rowNumConversions.add(IntBuffer.wrap(arr));
        }

        long time = System.currentTimeMillis();
        for (Rowboat theRow : theRows) {
            progress.progress();
            timeWriter.serialize(theRow.getTimestamp());

            final Object[] metrics = theRow.getMetrics();
            for (int i = 0; i < metrics.length; ++i) {
                metWriters.get(i).serialize(metrics[i]);
            }

            Object[] dims = theRow.getDims();
            for (int i = 0; i < dims.length; ++i) {
                DimensionMerger merger = mergers.get(i);
                if (merger.canSkip()) {
                    continue;
                }
                merger.processMergedRow(dims[i]);
            }

            Iterator<Int2ObjectMap.Entry<IntSortedSet>> rowsIterator = theRow.getComprisedRows()
                    .int2ObjectEntrySet().fastIterator();
            while (rowsIterator.hasNext()) {
                Int2ObjectMap.Entry<IntSortedSet> comprisedRow = rowsIterator.next();

                final IntBuffer conversionBuffer = rowNumConversions.get(comprisedRow.getIntKey());

                for (IntIterator setIterator = comprisedRow.getValue().iterator(); setIterator
                        .hasNext(); /* NOP */) {
                    int rowNum = setIterator.nextInt();
                    while (conversionBuffer.position() < rowNum) {
                        conversionBuffer.put(INVALID_ROW);
                    }
                    conversionBuffer.put(rowCount);
                }
            }

            if ((++rowCount % 500000) == 0) {
                log.info("walked 500,000/%d rows in %,d millis.", rowCount, System.currentTimeMillis() - time);
                time = System.currentTimeMillis();
            }
        }
        for (IntBuffer rowNumConversion : rowNumConversions) {
            rowNumConversion.rewind();
        }
        log.info("completed walk through of %,d rows in %,d millis.", rowCount,
                System.currentTimeMillis() - startTime);
        progress.stopSection(section);
    }

    private LongColumnSerializer setupTimeWriter(final IOPeon ioPeon, final IndexSpec indexSpec)
            throws IOException {
        LongColumnSerializer timeWriter = LongColumnSerializer.create(ioPeon, "little_end_time",
                CompressedObjectStrategy.DEFAULT_COMPRESSION_STRATEGY, indexSpec.getLongEncoding());
        // we will close this writer after we added all the timestamps
        timeWriter.open();
        return timeWriter;
    }

    private ArrayList<GenericColumnSerializer> setupMetricsWriters(final IOPeon ioPeon,
            final List<String> mergedMetrics, final Map<String, ValueType> metricsValueTypes,
            final Map<String, String> metricTypeNames, final IndexSpec indexSpec) throws IOException {
        ArrayList<GenericColumnSerializer> metWriters = Lists.newArrayListWithCapacity(mergedMetrics.size());
        final CompressedObjectStrategy.CompressionStrategy metCompression = indexSpec.getMetricCompression();
        final CompressionFactory.LongEncodingStrategy longEncoding = indexSpec.getLongEncoding();
        for (String metric : mergedMetrics) {
            ValueType type = metricsValueTypes.get(metric);
            GenericColumnSerializer writer;
            switch (type) {
            case LONG:
                writer = LongColumnSerializer.create(ioPeon, metric, metCompression, longEncoding);
                break;
            case FLOAT:
                writer = FloatColumnSerializer.create(ioPeon, metric, metCompression);
                break;
            case DOUBLE:
                writer = DoubleColumnSerializer.create(ioPeon, metric, metCompression);
                break;
            case COMPLEX:
                final String typeName = metricTypeNames.get(metric);
                ComplexMetricSerde serde = ComplexMetrics.getSerdeForType(typeName);
                if (serde == null) {
                    throw new ISE("Unknown type[%s]", typeName);
                }
                writer = serde.getSerializer(ioPeon, metric);
                break;
            default:
                throw new ISE("Unknown type[%s]", type);
            }
            writer.open();
            // we will close these writers in another method after we added all the metrics
            metWriters.add(writer);
        }
        return metWriters;
    }

    private void writeDimValueAndSetupDimConversion(final List<IndexableAdapter> indexes,
            final ProgressIndicator progress, final List<String> mergedDimensions,
            final List<DimensionMerger> mergers) throws IOException {
        final String section = "setup dimension conversions";
        progress.startSection(section);

        for (int dimIndex = 0; dimIndex < mergedDimensions.size(); ++dimIndex) {
            mergers.get(dimIndex).writeMergedValueMetadata(indexes);
        }
        progress.stopSection(section);
    }

    private void mergeCapabilities(final List<IndexableAdapter> adapters, final List<String> mergedDimensions,
            final Map<String, ValueType> metricsValueTypes, final Map<String, String> metricTypeNames,
            final List<ColumnCapabilitiesImpl> dimCapabilities) {
        final Map<String, ColumnCapabilitiesImpl> capabilitiesMap = Maps.newHashMap();
        for (IndexableAdapter adapter : adapters) {
            for (String dimension : adapter.getDimensionNames()) {
                ColumnCapabilitiesImpl mergedCapabilities = capabilitiesMap.get(dimension);
                if (mergedCapabilities == null) {
                    mergedCapabilities = new ColumnCapabilitiesImpl();
                    mergedCapabilities.setType(null);
                }
                capabilitiesMap.put(dimension, mergedCapabilities.merge(adapter.getCapabilities(dimension)));
            }
            for (String metric : adapter.getMetricNames()) {
                ColumnCapabilitiesImpl mergedCapabilities = capabilitiesMap.get(metric);
                ColumnCapabilities capabilities = adapter.getCapabilities(metric);
                if (mergedCapabilities == null) {
                    mergedCapabilities = new ColumnCapabilitiesImpl();
                }
                capabilitiesMap.put(metric, mergedCapabilities.merge(capabilities));
                metricsValueTypes.put(metric, capabilities.getType());
                metricTypeNames.put(metric, adapter.getMetricType(metric));
            }
        }
        for (String dim : mergedDimensions) {
            dimCapabilities.add(capabilitiesMap.get(dim));
        }
    }

    @Override
    public File persist(final IncrementalIndex index, File outDir, IndexSpec indexSpec) throws IOException {
        return persist(index, index.getInterval(), outDir, indexSpec);
    }

    @Override
    public File persist(final IncrementalIndex index, final Interval dataInterval, File outDir, IndexSpec indexSpec)
            throws IOException {
        return persist(index, dataInterval, outDir, indexSpec, new BaseProgressIndicator());
    }

    @Override
    public File persist(final IncrementalIndex index, final Interval dataInterval, File outDir, IndexSpec indexSpec,
            ProgressIndicator progress) throws IOException {
        if (index.isEmpty()) {
            throw new IAE("Trying to persist an empty index!");
        }

        final long firstTimestamp = index.getMinTime().getMillis();
        final long lastTimestamp = index.getMaxTime().getMillis();
        if (!(dataInterval.contains(firstTimestamp) && dataInterval.contains(lastTimestamp))) {
            throw new IAE("interval[%s] does not encapsulate the full range of timestamps[%s, %s]", dataInterval,
                    new DateTime(firstTimestamp), new DateTime(lastTimestamp));
        }

        FileUtils.forceMkdir(outDir);

        log.info("Starting persist for interval[%s], rows[%,d]", dataInterval, index.size());
        return merge(
                Arrays.<IndexableAdapter>asList(new IncrementalIndexAdapter(dataInterval, index,
                        indexSpec.getBitmapSerdeFactory().getBitmapFactory())),
                // if index is not rolled up, then it should be not rollup here
                // if index is rolled up, then it is no need to rollup again.
                //                     In this case, true/false won't cause reOrdering in merge stage
                //                     while merging a single iterable
                false, index.getMetricAggs(), outDir, indexSpec, progress);
    }

    @Override
    public File mergeQueryableIndex(List<QueryableIndex> indexes, boolean rollup,
            final AggregatorFactory[] metricAggs, File outDir, IndexSpec indexSpec) throws IOException {
        return mergeQueryableIndex(indexes, rollup, metricAggs, outDir, indexSpec, new BaseProgressIndicator());
    }

    @Override
    public File mergeQueryableIndex(List<QueryableIndex> indexes, boolean rollup,
            final AggregatorFactory[] metricAggs, File outDir, IndexSpec indexSpec, ProgressIndicator progress)
            throws IOException {
        return merge(IndexMerger.toIndexableAdapters(indexes), rollup, metricAggs, outDir, indexSpec, progress);
    }

    @Override
    public File merge(List<IndexableAdapter> indexes, boolean rollup, final AggregatorFactory[] metricAggs,
            File outDir, IndexSpec indexSpec) throws IOException {
        return merge(indexes, rollup, metricAggs, outDir, indexSpec, new BaseProgressIndicator());
    }

    @Override
    public File merge(List<IndexableAdapter> indexes, final boolean rollup, final AggregatorFactory[] metricAggs,
            File outDir, IndexSpec indexSpec, ProgressIndicator progress) throws IOException {
        FileUtils.deleteDirectory(outDir);
        FileUtils.forceMkdir(outDir);

        final List<String> mergedDimensions = IndexMerger.getMergedDimensions(indexes);

        final List<String> mergedMetrics = Lists.transform(IndexMerger.mergeIndexed(Lists.newArrayList(
                FunctionalIterable.create(indexes).transform(new Function<IndexableAdapter, Iterable<String>>() {
                    @Override
                    public Iterable<String> apply(@Nullable IndexableAdapter input) {
                        return input.getMetricNames();
                    }
                }))), new Function<String, String>() {
                    @Override
                    public String apply(@Nullable String input) {
                        return input;
                    }
                });

        final AggregatorFactory[] sortedMetricAggs = new AggregatorFactory[mergedMetrics.size()];
        for (AggregatorFactory metricAgg : metricAggs) {
            int metricIndex = mergedMetrics.indexOf(metricAgg.getName());
            /*
              If metricIndex is negative, one of the metricAggs was not present in the union of metrics from the indices
              we are merging
             */
            if (metricIndex > -1) {
                sortedMetricAggs[metricIndex] = metricAgg;
            }
        }

        /*
          If there is nothing at sortedMetricAggs[i], then we did not have a metricAgg whose name matched the name
          of the ith element of mergedMetrics. I.e. There was a metric in the indices to merge that we did not ask for.
         */
        for (int i = 0; i < sortedMetricAggs.length; i++) {
            if (sortedMetricAggs[i] == null) {
                throw new IAE("Indices to merge contained metric[%s], but requested metrics did not",
                        mergedMetrics.get(i));
            }
        }

        for (int i = 0; i < mergedMetrics.size(); i++) {
            if (!sortedMetricAggs[i].getName().equals(mergedMetrics.get(i))) {
                throw new IAE("Metric mismatch, index[%d] [%s] != [%s]", i, sortedMetricAggs[i].getName(),
                        mergedMetrics.get(i));
            }
        }

        Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>> rowMergerFn = new Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>>() {
            @Override
            public Iterable<Rowboat> apply(@Nullable ArrayList<Iterable<Rowboat>> boats) {
                if (rollup) {
                    return CombiningIterable.create(new MergeIterable<>(Comparators.naturalNullsFirst(), boats),
                            Comparators.naturalNullsFirst(), new RowboatMergeFunction(sortedMetricAggs));
                } else {
                    return new MergeIterable<Rowboat>(new Ordering<Rowboat>() {
                        @Override
                        public int compare(Rowboat left, Rowboat right) {
                            return Longs.compare(left.getTimestamp(), right.getTimestamp());
                        }
                    }.nullsFirst(), boats);
                }
            }
        };

        return makeIndexFiles(indexes, sortedMetricAggs, outDir, progress, mergedDimensions, mergedMetrics,
                rowMergerFn, indexSpec);
    }

    @Override
    public File convert(final File inDir, final File outDir, final IndexSpec indexSpec) throws IOException {
        return convert(inDir, outDir, indexSpec, new BaseProgressIndicator());
    }

    @Override
    public File convert(final File inDir, final File outDir, final IndexSpec indexSpec,
            final ProgressIndicator progress) throws IOException {
        try (QueryableIndex index = indexIO.loadIndex(inDir)) {
            final IndexableAdapter adapter = new QueryableIndexIndexableAdapter(index);
            return makeIndexFiles(ImmutableList.of(adapter), null, outDir, progress,
                    Lists.newArrayList(adapter.getDimensionNames()), Lists.newArrayList(adapter.getMetricNames()),
                    new Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>>() {
                        @Nullable
                        @Override
                        public Iterable<Rowboat> apply(ArrayList<Iterable<Rowboat>> input) {
                            return input.get(0);
                        }
                    }, indexSpec);
        }
    }

    @Override
    public File append(List<IndexableAdapter> indexes, AggregatorFactory[] aggregators, File outDir,
            IndexSpec indexSpec) throws IOException {
        return append(indexes, aggregators, outDir, indexSpec, new BaseProgressIndicator());
    }

    @Override
    public File append(List<IndexableAdapter> indexes, AggregatorFactory[] aggregators, File outDir,
            IndexSpec indexSpec, ProgressIndicator progress) throws IOException {
        FileUtils.deleteDirectory(outDir);
        FileUtils.forceMkdir(outDir);

        final List<String> mergedDimensions = IndexMerger.getMergedDimensions(indexes);

        final List<String> mergedMetrics = IndexMerger
                .mergeIndexed(Lists.transform(indexes, new Function<IndexableAdapter, Iterable<String>>() {
                    @Override
                    public Iterable<String> apply(@Nullable IndexableAdapter input) {
                        return Iterables.transform(input.getMetricNames(), new Function<String, String>() {
                            @Override
                            public String apply(@Nullable String input) {
                                return input;
                            }
                        });
                    }
                }));

        Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>> rowMergerFn = new Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>>() {
            @Override
            public Iterable<Rowboat> apply(@Nullable final ArrayList<Iterable<Rowboat>> boats) {
                return new MergeIterable<>(Comparators.naturalNullsFirst(), boats);
            }
        };

        return makeIndexFiles(indexes, aggregators, outDir, progress, mergedDimensions, mergedMetrics, rowMergerFn,
                indexSpec);
    }

    private DimensionHandler[] makeDimensionHandlers(final List<String> mergedDimensions,
            final List<ColumnCapabilitiesImpl> dimCapabilities) {
        final DimensionHandler[] handlers = new DimensionHandler[mergedDimensions.size()];
        for (int i = 0; i < mergedDimensions.size(); i++) {
            ColumnCapabilities capabilities = dimCapabilities.get(i);
            String dimName = mergedDimensions.get(i);
            handlers[i] = DimensionHandlerUtils.getHandlerFromCapabilities(dimName, capabilities, null);
        }
        return handlers;
    }

    private Iterable<Rowboat> makeRowIterable(List<IndexableAdapter> indexes, final List<String> mergedDimensions,
            final List<String> mergedMetrics, Function<ArrayList<Iterable<Rowboat>>, Iterable<Rowboat>> rowMergerFn,
            final List<ColumnCapabilitiesImpl> dimCapabilities, final DimensionHandler[] handlers,
            final List<DimensionMerger> mergers) {
        ArrayList<Iterable<Rowboat>> boats = Lists.newArrayListWithCapacity(indexes.size());

        for (int i = 0; i < indexes.size(); ++i) {
            final IndexableAdapter adapter = indexes.get(i);

            final int[] dimLookup = getColumnIndexReorderingMap(adapter.getDimensionNames(), mergedDimensions);
            final int[] metricLookup = getColumnIndexReorderingMap(adapter.getMetricNames(), mergedMetrics);

            Iterable<Rowboat> target = indexes.get(i).getRows();
            if (dimLookup != null || metricLookup != null) {
                // resize/reorder index table if needed
                target = Iterables.transform(target, new Function<Rowboat, Rowboat>() {
                    @Override
                    public Rowboat apply(Rowboat input) {
                        Object[] newDims;
                        if (dimLookup != null) {
                            newDims = new Object[mergedDimensions.size()];
                            int j = 0;
                            for (Object dim : input.getDims()) {
                                newDims[dimLookup[j]] = dim;
                                j++;
                            }
                        } else {
                            // It's possible for getColumnIndexReorderingMap to return null when
                            // both column lists are identical. Copy the old array, no dimension reordering is needed.
                            newDims = input.getDims();
                        }

                        Object[] newMetrics = input.getMetrics();
                        if (metricLookup != null) {
                            newMetrics = new Object[mergedMetrics.size()];
                            int j = 0;
                            for (Object met : input.getMetrics()) {
                                newMetrics[metricLookup[j]] = met;
                                j++;
                            }
                        }

                        return new Rowboat(input.getTimestamp(), newDims, newMetrics, input.getRowNum(), handlers);
                    }
                });
            }
            boats.add(new MMappedIndexRowIterable(target, mergedDimensions, i, dimCapabilities, mergers));
        }

        return rowMergerFn.apply(boats);
    }

    // If an adapter's column list differs from the merged column list across multiple indexes,
    // return an array that maps the adapter's column orderings to the larger, merged column ordering
    private int[] getColumnIndexReorderingMap(Indexed<String> adapterColumnNames, List<String> mergedColumnNames) {
        if (isSame(adapterColumnNames, mergedColumnNames)) {
            return null; // no need to convert if column lists are identical
        }
        int[] dimLookup = new int[mergedColumnNames.size()];
        for (int i = 0; i < adapterColumnNames.size(); i++) {
            dimLookup[i] = mergedColumnNames.indexOf(adapterColumnNames.get(i));
        }
        return dimLookup;
    }

    private boolean isSame(Indexed<String> indexed, List<String> values) {
        if (indexed.size() != values.size()) {
            return false;
        }
        for (int i = 0; i < indexed.size(); i++) {
            if (!indexed.get(i).equals(values.get(i))) {
                return false;
            }
        }
        return true;
    }

}