test/unit/org/apache/cassandra/dht/KeyCollisionTest.java

/*
 * 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.cassandra.dht;

import java.math.BigInteger;
import java.util.List;

import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.Test;

import org.apache.cassandra.SchemaLoader;
import org.apache.cassandra.Util;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.config.Schema;
import org.apache.cassandra.db.ColumnFamilyStore;
import org.apache.cassandra.db.Keyspace;
import org.apache.cassandra.db.RowUpdateBuilder;
import org.apache.cassandra.db.partitions.*;
import org.apache.cassandra.exceptions.ConfigurationException;
import org.apache.cassandra.schema.KeyspaceParams;
import org.apache.cassandra.service.StorageService;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.FBUtilities;

/**
 * Test cases where multiple keys collides, ie have the same token.
 * Order preserving partitioner have no possible collision and creating
 * collision for the RandomPartitioner is ... difficult, so we create a dumb
 * length partitioner that takes the length of the key as token, making
 * collision easy and predictable.
 */
public class KeyCollisionTest
{
    static IPartitioner oldPartitioner;
    private static final String KEYSPACE1 = "KeyCollisionTest1";
    private static final String CF = "Standard1";

    @BeforeClass
    public static void defineSchema() throws ConfigurationException
    {
        oldPartitioner = StorageService.instance.setPartitionerUnsafe(LengthPartitioner.instance);
        SchemaLoader.prepareServer();
        SchemaLoader.createKeyspace(KEYSPACE1,
                                    KeyspaceParams.simple(1),
                                    SchemaLoader.standardCFMD(KEYSPACE1, CF));
    }

    @AfterClass
    public static void tearDown()
    {
        DatabaseDescriptor.setPartitionerUnsafe(oldPartitioner);
    }

    @Test
    public void testGetSliceWithCollision() throws Exception
    {
        Keyspace keyspace = Keyspace.open(KEYSPACE1);
        ColumnFamilyStore cfs = keyspace.getColumnFamilyStore(CF);
        cfs.clearUnsafe();

        insert("k1", "k2", "kq");       // token = 2, kq ordered after row below lexicographically
        insert("key1", "key2", "key3"); // token = 4
        insert("longKey1", "longKey2"); // token = 8

        List<FilteredPartition> partitions = Util.getAll(Util.cmd(cfs).fromKeyIncl("k2").toKeyIncl("key2").build());

        assert partitions.get(0).partitionKey().getKey().equals(ByteBufferUtil.bytes("k2"));
        assert partitions.get(1).partitionKey().getKey().equals(ByteBufferUtil.bytes("kq"));
        assert partitions.get(2).partitionKey().getKey().equals(ByteBufferUtil.bytes("key1"));
        assert partitions.get(3).partitionKey().getKey().equals(ByteBufferUtil.bytes("key2"));
    }

    private void insert(String... keys)
    {
        for (String key : keys)
            insert(key);
    }

    private void insert(String key)
    {
        RowUpdateBuilder builder = new RowUpdateBuilder(Schema.instance.getCFMetaData(KEYSPACE1, CF), FBUtilities.timestampMicros(), key);
        builder.clustering("c").add("val", "asdf").build().applyUnsafe();
    }

    static class BigIntegerToken extends ComparableObjectToken<BigInteger>
    {
        private static final long serialVersionUID = 1L;

        public BigIntegerToken(BigInteger token)
        {
            super(token);
        }

        // convenience method for testing
        public BigIntegerToken(String token) {
            this(new BigInteger(token));
        }

        @Override
        public IPartitioner getPartitioner()
        {
            return LengthPartitioner.instance;
        }

        @Override
        public long getHeapSize()
        {
            return 0;
        }
    }
}