test/unit/org/apache/cassandra/io/sstable/metadata/MetadataSerializerTest.java

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 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
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 *     http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.cassandra.io.sstable.metadata;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.EnumSet;
import java.util.Map;
import java.util.Set;

import com.google.common.collect.Sets;

import org.junit.Test;

import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.db.commitlog.ReplayPosition;
import org.apache.cassandra.db.composites.SimpleDenseCellNameType;
import org.apache.cassandra.db.marshal.BytesType;
import org.apache.cassandra.dht.RandomPartitioner;
import org.apache.cassandra.io.sstable.Component;
import org.apache.cassandra.io.sstable.Descriptor;
import org.apache.cassandra.io.sstable.format.Version;
import org.apache.cassandra.io.sstable.format.big.BigFormat;
import org.apache.cassandra.io.util.DataOutputStreamPlus;
import org.apache.cassandra.io.util.BufferedDataOutputStreamPlus;
import org.apache.cassandra.io.util.RandomAccessReader;
import org.apache.cassandra.utils.EstimatedHistogram;

import static org.junit.Assert.assertEquals;

public class MetadataSerializerTest
{
    @Test
    public void testSerialization() throws IOException
    {
        Map<MetadataType, MetadataComponent> originalMetadata = constructMetadata();

        MetadataSerializer serializer = new MetadataSerializer();
        File statsFile = serialize(originalMetadata, serializer, BigFormat.latestVersion);

        Descriptor desc = new Descriptor( statsFile.getParentFile(), "", "", 0, Descriptor.Type.FINAL);
        try (RandomAccessReader in = RandomAccessReader.open(statsFile))
        {
            Map<MetadataType, MetadataComponent> deserialized = serializer.deserialize(desc, in, EnumSet.allOf(MetadataType.class));

            for (MetadataType type : MetadataType.values())
            {
                assertEquals(originalMetadata.get(type), deserialized.get(type));
            }
        }
    }

    public File serialize(Map<MetadataType, MetadataComponent> metadata, MetadataSerializer serializer, Version version)
            throws IOException, FileNotFoundException
    {
        // Serialize to tmp file
        File statsFile = File.createTempFile(Component.STATS.name, null);
        try (DataOutputStreamPlus out = new BufferedDataOutputStreamPlus(new FileOutputStream(statsFile)))
        {
            serializer.serialize(metadata, version, out);
        }
        return statsFile;
    }

    public Map<MetadataType, MetadataComponent> constructMetadata()
    {
        EstimatedHistogram rowSizes = new EstimatedHistogram(new long[] { 1L, 2L },
                                                             new long[] { 3L, 4L, 5L });
        EstimatedHistogram columnCounts = new EstimatedHistogram(new long[] { 6L, 7L },
                                                                 new long[] { 8L, 9L, 10L });
        ReplayPosition start = new ReplayPosition(11L, 12);
        ReplayPosition end = new ReplayPosition(15L, 9);
        long minTimestamp = 2162517136L;
        long maxTimestamp = 4162517136L;

        MetadataCollector collector = new MetadataCollector(new SimpleDenseCellNameType(BytesType.instance))
                                                      .estimatedRowSize(rowSizes)
                                                      .estimatedColumnCount(columnCounts)
                                                      .commitLogLowerBound(start)
                                                      .commitLogUpperBound(end);
        collector.updateMinTimestamp(minTimestamp);
        collector.updateMaxTimestamp(maxTimestamp);

        Set<Integer> ancestors = Sets.newHashSet(1, 2, 3, 4);
        for (int i : ancestors)
            collector.addAncestor(i);

        String partitioner = RandomPartitioner.class.getCanonicalName();
        double bfFpChance = 0.1;
        Map<MetadataType, MetadataComponent> originalMetadata = collector.finalizeMetadata(partitioner, bfFpChance, 0);
        return originalMetadata;
    }

    @Test
    public void testLaReadsLb() throws IOException
    {
        Map<MetadataType, MetadataComponent> originalMetadata = constructMetadata();

        MetadataSerializer serializer = new MetadataSerializer();
        // Write metadata in two minor formats.
        File statsFileLb = serialize(originalMetadata, serializer, BigFormat.instance.getVersion("lb"));
        File statsFileLa = serialize(originalMetadata, serializer, BigFormat.instance.getVersion("la"));

        // Reading both as earlier version should yield identical results.
        Descriptor desc = new Descriptor("la", statsFileLb.getParentFile(), "", "", 0, Descriptor.Type.FINAL, DatabaseDescriptor.getSSTableFormat());
        try (RandomAccessReader inLb = RandomAccessReader.open(statsFileLb);
             RandomAccessReader inLa = RandomAccessReader.open(statsFileLa))
        {
            Map<MetadataType, MetadataComponent> deserializedLb = serializer.deserialize(desc, inLb, EnumSet.allOf(MetadataType.class));
            Map<MetadataType, MetadataComponent> deserializedLa = serializer.deserialize(desc, inLa, EnumSet.allOf(MetadataType.class));

            for (MetadataType type : MetadataType.values())
            {
                assertEquals(deserializedLa.get(type), deserializedLb.get(type));
                if (!originalMetadata.get(type).equals(deserializedLb.get(type)))
                {
                    // Currently only STATS can be different. Change if no longer the case
                    assertEquals(MetadataType.STATS, type);
                }
            }
        }
    }
}