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 * 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.test.microbench;

import java.util.ArrayList;
import java.util.List;
import java.util.Random;
import java.util.concurrent.TimeUnit;

import org.junit.Assert;
import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Level;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Param;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.Setup;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.TearDown;
import org.openjdk.jmh.annotations.Threads;
import org.openjdk.jmh.annotations.Warmup;

import org.apache.cassandra.ServerTestUtils;
import org.apache.cassandra.Util;
import org.apache.cassandra.cache.AutoSavingCache;
import org.apache.cassandra.cache.KeyCacheKey;
import org.apache.cassandra.config.Config;
import org.apache.cassandra.config.DataStorageSpec;
import org.apache.cassandra.config.DatabaseDescriptor;
import org.apache.cassandra.cql3.QueryProcessor;
import org.apache.cassandra.db.ColumnFamilyStore;
import org.apache.cassandra.db.Keyspace;
import org.apache.cassandra.db.RowUpdateBuilder;
import org.apache.cassandra.db.marshal.AsciiType;
import org.apache.cassandra.io.sstable.AbstractRowIndexEntry;
import org.apache.cassandra.io.sstable.format.SSTableReader;
import org.apache.cassandra.schema.ColumnMetadata;
import org.apache.cassandra.service.CacheService;
import org.apache.cassandra.utils.ByteBufferUtil;
import org.apache.cassandra.utils.TestHelper;

@SuppressWarnings("unused")
@BenchmarkMode(Mode.SampleTime)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
@Warmup(iterations = 1, time = 5, timeUnit = TimeUnit.SECONDS)
@Measurement(iterations = 1, time = 10, timeUnit = TimeUnit.SECONDS)
@Fork(value = 1)
@Threads(1)
@State(Scope.Benchmark)
public class CacheLoaderBench
{
    private static final int numSSTables = 100;
    private static final int numKeysPerTable = 10000;

    private final Random random = new Random();

    @Param({ "true", "false" })
    boolean useUUIDGenerationIdentifiers;

    @Setup(Level.Trial)
    public void setup() throws Throwable
    {
        DatabaseDescriptor.daemonInitialization(() -> {
            Config config = DatabaseDescriptor.loadConfig();
            config.key_cache_size = new DataStorageSpec.LongMebibytesBound(256);
            config.uuid_sstable_identifiers_enabled = useUUIDGenerationIdentifiers;
            config.dump_heap_on_uncaught_exception = false;
            return config;
        });
        ServerTestUtils.prepareServer();

        String keyspace = "ks";
        String table1 = "tab1";
        String table2 = "tab2";

        QueryProcessor.executeInternal(String.format("CREATE KEYSPACE %s with replication = { 'class' : 'SimpleStrategy', 'replication_factor' : 1 } and durable_writes = false", keyspace));
        QueryProcessor.executeInternal(String.format("CREATE TABLE %s.%s (key text PRIMARY KEY, val text)", keyspace, table1));
        QueryProcessor.executeInternal(String.format("CREATE TABLE %s.%s (key text PRIMARY KEY, val text)", keyspace, table2));

        Keyspace.system().forEach(k -> k.getColumnFamilyStores().forEach(ColumnFamilyStore::disableAutoCompaction));

        ColumnFamilyStore cfs1 = Keyspace.open(keyspace).getColumnFamilyStore(table1);
        ColumnFamilyStore cfs2 = Keyspace.open(keyspace).getColumnFamilyStore(table2);
        cfs1.disableAutoCompaction();
        cfs2.disableAutoCompaction();

        // Write a bunch of sstables to both cfs1 and cfs2

        List<ColumnFamilyStore> columnFamilyStores = new ArrayList<>(2);
        columnFamilyStores.add(cfs1);
        columnFamilyStores.add(cfs2);

        for (ColumnFamilyStore cfs: columnFamilyStores)
        {
            cfs.truncateBlocking();
            for (int i = 0; i < numSSTables ; i++)
            {
                ColumnMetadata colDef = ColumnMetadata.regularColumn(cfs.metadata(), ByteBufferUtil.bytes("val"), AsciiType.instance, ColumnMetadata.NO_UNIQUE_ID);
                for (int k = 0; k < numKeysPerTable; k++)
                {
                    RowUpdateBuilder rowBuilder = new RowUpdateBuilder(cfs.metadata(), System.currentTimeMillis() + random.nextInt(), "key" + k);
                    rowBuilder.add(colDef, "val1");
                    rowBuilder.build().apply();
                }
                cfs.forceBlockingFlush(ColumnFamilyStore.FlushReason.USER_FORCED);
            }

            Assert.assertEquals(numSSTables, cfs.getLiveSSTables().size());

            // preheat key cache
            for (SSTableReader sstable : cfs.getLiveSSTables())
            {
                for (int k = 0; k < numKeysPerTable; k++)
                {
                    sstable.getPosition(Util.dk("key" + k), SSTableReader.Operator.EQ);
                }
            }
        }

        AutoSavingCache<KeyCacheKey, AbstractRowIndexEntry> keyCache = CacheService.instance.keyCache;

        // serialize to file
        keyCache.submitWrite(keyCache.size()).get();
    }

    @Setup(Level.Invocation)
    public void setupKeyCache()
    {
        AutoSavingCache<KeyCacheKey, AbstractRowIndexEntry> keyCache = CacheService.instance.keyCache;
        keyCache.clear();
    }

    @TearDown(Level.Trial)
    public void teardown() throws Exception
    {
        TestHelper.teardown();
    }

    @Benchmark
    public void keyCacheLoadTest() throws Throwable
    {
        AutoSavingCache<KeyCacheKey, AbstractRowIndexEntry> keyCache = CacheService.instance.keyCache;

        keyCache.loadSavedAsync().get();
    }
}
