NativeNonUniqueSchemaNumberIndexPopulator.java

/*
 * Copyright (c) 2002-2017 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.kernel.impl.index.schema;

import java.io.File;
import java.io.IOException;

import org.neo4j.index.internal.gbptree.Layout;
import org.neo4j.index.internal.gbptree.RecoveryCleanupWorkCollector;
import org.neo4j.io.pagecache.PageCache;
import org.neo4j.kernel.api.index.IndexEntryUpdate;
import org.neo4j.kernel.impl.api.index.sampling.DefaultNonUniqueIndexSampler;
import org.neo4j.kernel.impl.api.index.sampling.IndexSamplingConfig;
import org.neo4j.kernel.impl.api.index.sampling.NonUniqueIndexSampler;
import org.neo4j.storageengine.api.schema.IndexSample;

/**
 * {@link NativeSchemaNumberIndexPopulator} which can accept duplicate values (for different entity ids).
 */
class NativeNonUniqueSchemaNumberIndexPopulator<KEY extends NumberKey, VALUE extends NumberValue>
        extends NativeSchemaNumberIndexPopulator<KEY,VALUE>
{
    private final IndexSamplingConfig samplingConfig;
    private boolean updateSampling;
    private NonUniqueIndexSampler sampler;

    NativeNonUniqueSchemaNumberIndexPopulator( PageCache pageCache, File storeFile, Layout<KEY,VALUE> layout,
            RecoveryCleanupWorkCollector recoveryCleanupWorkCollector, IndexSamplingConfig samplingConfig )
    {
        super( pageCache, storeFile, layout, recoveryCleanupWorkCollector );
        this.samplingConfig = samplingConfig;
    }

    @Override
    public void includeSample( IndexEntryUpdate update )
    {
        if ( updateSampling )
        {
            checkSampler();
            sampler.include( SamplingUtil.encodedStringValuesForSampling( update.values() ) );
        }
    }

    @Override
    public void configureSampling( boolean onlineSampling )
    {
        this.updateSampling = onlineSampling;
        this.sampler = onlineSampling ? new DefaultNonUniqueIndexSampler( samplingConfig.sampleSizeLimit() )
                                      : new FullScanNonUniqueIndexSampler<>( tree, layout, samplingConfig );
    }

    @Override
    public IndexSample sampleResult()
    {
        checkSampler();

        // Close the writer before scanning
        try
        {
            closeWriter();
        }
        catch ( IOException e )
        {
            throw new RuntimeException( e );
        }

        try
        {
            return sampler.result();
        }
        finally
        {
            // Start the writer again (TODO may be unnecessary)
            try
            {
                instantiateWriter();
            }
            catch ( IOException e )
            {
                throw new RuntimeException( e );
            }
        }
    }

    private void checkSampler()
    {
        if ( sampler == null )
        {
            throw new IllegalStateException( "Please configure populator sampler before using it." );
        }
    }
}