import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
@Test
public void testKeyCacheNonClustered() throws Throwable
{
    String table = createTable("CREATE TABLE %s ("
                               + commonColumnsDef
                               + "PRIMARY KEY ((part_key_a, part_key_b)))");
    insertData(table, null, false);
    clearCache();

    for (int i = 0; i < 10; i++)
    {
        assertRows(execute("SELECT col_text FROM %s WHERE part_key_a = ? AND part_key_b = ?", i, Integer.toOctalString(i)),
                   new Object[]{ String.valueOf(i) + '-' + String.valueOf(0) });
    }

    CacheMetrics metrics = CacheService.instance.keyCache.getMetrics();
    long hits = metrics.hits.getCount();
    long requests = metrics.requests.getCount();
    assertEquals(0, hits);
    assertEquals(10, requests);

    for (int i = 0; i < 100; i++)
    {
        assertRows(execute("SELECT col_text FROM %s WHERE part_key_a = ? AND part_key_b = ?", i, Integer.toOctalString(i)),
                   new Object[]{ String.valueOf(i) + '-' + String.valueOf(0) });
    }

    hits = metrics.hits.getCount();
    requests = metrics.requests.getCount();
    assertEquals(10, hits);
    assertEquals(120, requests);
}
 

import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
private static void clearCache()
{
    CassandraMetricsRegistry.Metrics.getNames().forEach(CassandraMetricsRegistry.Metrics::remove);
    CacheService.instance.keyCache.clear();
    CacheMetrics metrics = CacheService.instance.keyCache.getMetrics();
    Assert.assertEquals(0, metrics.entries.getValue().intValue());
    Assert.assertEquals(0L, metrics.hits.getCount());
    Assert.assertEquals(0L, metrics.requests.getCount());
    Assert.assertEquals(0L, metrics.size.getValue().longValue());
}
 

import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
public CacheService(APIClient client) {
    super(MBEAN_NAME, client, new CacheMetrics("KeyCache", "key"), new CacheMetrics("RowCache", "row"),
            new CacheMetrics("CounterCache", "counter"));
}
 

import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
public InstrumentingCache(String type, ICache<K, V> map)
{
    this.map = map;
    this.type = type;
    this.metrics = new CacheMetrics(type, map);
}
 

import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
public void clear()
{
    map.clear();
    metrics = new CacheMetrics(type, map);
}
 

import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
public CacheMetrics getMetrics()
{
    return metrics;
}
 

import org.apache.cassandra.metrics.CacheMetrics; //导入依赖的package包/类
@Test
public void testKeyCacheClustered() throws Throwable
{
    String table = createTable("CREATE TABLE %s ("
                               + commonColumnsDef
                               + "PRIMARY KEY ((part_key_a, part_key_b),clust_key_a,clust_key_b,clust_key_c))");
    insertData(table, null, true);
    clearCache();

    // query on partition key

    // 10 queries, each 50 result rows
    for (int i = 0; i < 10; i++)
    {
        assertEquals(50, execute("SELECT col_text FROM %s WHERE part_key_a = ? AND part_key_b = ?", i, Integer.toOctalString(i)).size());
    }

    CacheMetrics metrics = CacheService.instance.keyCache.getMetrics();
    long hits = metrics.hits.getCount();
    long requests = metrics.requests.getCount();
    assertEquals(0, hits);
    assertEquals(10, requests);

    // 10 queries, each 50 result rows
    for (int i = 0; i < 10; i++)
    {
        assertEquals(50, execute("SELECT col_text FROM %s WHERE part_key_a = ? AND part_key_b = ?", i, Integer.toOctalString(i)).size());
    }

    metrics = CacheService.instance.keyCache.getMetrics();
    hits = metrics.hits.getCount();
    requests = metrics.requests.getCount();
    assertEquals(10, hits);
    assertEquals(10 + 10, requests);

    // 100 queries - must get a hit in key-cache
    for (int i = 0; i < 10; i++)
    {
        for (int c = 0; c < 10; c++)
        {
            assertRows(execute("SELECT col_text, col_long FROM %s WHERE part_key_a = ? AND part_key_b = ? and clust_key_a = ?", i, Integer.toOctalString(i), c),
                       new Object[]{ String.valueOf(i) + '-' + String.valueOf(c), (long) c });
        }
    }

    metrics = CacheService.instance.keyCache.getMetrics();
    hits = metrics.hits.getCount();
    requests = metrics.requests.getCount();
    assertEquals(10 + 100, hits);
    assertEquals(20 + 100, requests);

    // 5000 queries - first 10 partitions already in key cache
    for (int i = 0; i < 100; i++)
    {
        for (int c = 0; c < 50; c++)
        {
            assertRows(execute("SELECT col_text, col_long FROM %s WHERE part_key_a = ? AND part_key_b = ? and clust_key_a = ?", i, Integer.toOctalString(i), c),
                       new Object[]{ String.valueOf(i) + '-' + String.valueOf(c), (long) c });
        }
    }

    hits = metrics.hits.getCount();
    requests = metrics.requests.getCount();
    assertEquals(110 + 4910, hits);
    assertEquals(120 + 5500, requests);
}