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1. 一普通同步方式
2. 二事务方式Transactions
3. 三管道Pipelining
4. 四管道中调用事务
5. 五分布式直连同步调用
6. 六分布式直连异步调用
7. 七分布式连接池同步调用
8. 八分布式连接池异步调用
9. 九需要注意的地方
10. 十测试
11. 十一完整的测试代码

    redis是一个著名的key-value存储系统，而作为其官方推荐的java版客户端jedis也非常强大和稳定，支持事务、管道及有jedis自身实现的分布式。

    在这里对jedis关于事务、管道和分布式的调用方式做一个简单的介绍和对比：

    一、普通同步方式

    最简单和基础的调用方式，

    @Test
    public void test1Normal() {Jedis jedis = new Jedis("localhost");long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {String result = jedis.set("n" + i, "n" + i);}long end = System.currentTimeMillis();System.out.println("Simple SET: " + ((end - start)/1000.0) + " seconds");jedis.disconnect();
    }
    

    很简单吧，每次set之后都可以返回结果，标记是否成功。

    二、事务方式(Transactions)

    redis的事务很简单，他主要目的是保障，一个client发起的事务中的命令可以连续的执行，而中间不会插入其他client的命令。

    看下面例子：

    @Test
    public void test2Trans() {Jedis jedis = new Jedis("localhost");long start = System.currentTimeMillis();Transaction tx = jedis.multi();for (int i = 0; i < 100000; i++) {tx.set("t" + i, "t" + i);}List<Object> results = tx.exec();long end = System.currentTimeMillis();System.out.println("Transaction SET: " + ((end - start)/1000.0) + " seconds");jedis.disconnect();
    }
    

    我们调用jedis.watch(…)方法来监控key，如果调用后key值发生变化，则整个事务会执行失败。另外，事务中某个操作失败，并不会回滚其他操作。这一点需要注意。还有，我们可以使用discard()方法来取消事务。

    三、管道(Pipelining)

    有时，我们需要采用异步方式，一次发送多个指令，不同步等待其返回结果。这样可以取得非常好的执行效率。这就是管道，调用方法如下：

    @Test
    public void test3Pipelined() {Jedis jedis = new Jedis("localhost");Pipeline pipeline = jedis.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("p" + i, "p" + i);}List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();System.out.println("Pipelined SET: " + ((end - start)/1000.0) + " seconds");jedis.disconnect();
    }
    

    四、管道中调用事务

    就Jedis提供的方法而言，是可以做到在管道中使用事务，其代码如下：

    @Test
    public void test4combPipelineTrans() {jedis = new Jedis("localhost"); long start = System.currentTimeMillis();Pipeline pipeline = jedis.pipelined();pipeline.multi();for (int i = 0; i < 100000; i++) {pipeline.set("" + i, "" + i);}pipeline.exec();List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();System.out.println("Pipelined transaction: " + ((end - start)/1000.0) + " seconds");jedis.disconnect();
    }
    

    但是经测试（见本文后续部分），发现其效率和单独使用事务差不多，甚至还略微差点。

    五、分布式直连同步调用

    @Test
    public void test5shardNormal() {List<JedisShardInfo> shards = Arrays.asList(new JedisShardInfo("localhost",6379),new JedisShardInfo("localhost",6380));ShardedJedis sharding = new ShardedJedis(shards);long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {String result = sharding.set("sn" + i, "n" + i);}long end = System.currentTimeMillis();System.out.println("Simple@Sharing SET: " + ((end - start)/1000.0) + " seconds");sharding.disconnect();
    }
    

    这个是分布式直接连接，并且是同步调用，每步执行都返回执行结果。类似地，还有异步管道调用。

    六、分布式直连异步调用

    @Test
    public void test6shardpipelined() {List<JedisShardInfo> shards = Arrays.asList(new JedisShardInfo("localhost",6379),new JedisShardInfo("localhost",6380));ShardedJedis sharding = new ShardedJedis(shards);ShardedJedisPipeline pipeline = sharding.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("sp" + i, "p" + i);}List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();System.out.println("Pipelined@Sharing SET: " + ((end - start)/1000.0) + " seconds");sharding.disconnect();
    }
    

    七、分布式连接池同步调用

    如果，你的分布式调用代码是运行在线程中，那么上面两个直连调用方式就不合适了，因为直连方式是非线程安全的，这个时候，你就必须选择连接池调用。

    @Test
    public void test7shardSimplePool() {List<JedisShardInfo> shards = Arrays.asList(new JedisShardInfo("localhost",6379),new JedisShardInfo("localhost",6380));ShardedJedisPool pool = new ShardedJedisPool(new JedisPoolConfig(), shards);ShardedJedis one = pool.getResource();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {String result = one.set("spn" + i, "n" + i);}long end = System.currentTimeMillis();pool.returnResource(one);System.out.println("Simple@Pool SET: " + ((end - start)/1000.0) + " seconds");pool.destroy();
    }
    

    上面是同步方式，当然还有异步方式。

    八、分布式连接池异步调用

    @Test
    public void test8shardPipelinedPool() {List<JedisShardInfo> shards = Arrays.asList(new JedisShardInfo("localhost",6379),new JedisShardInfo("localhost",6380));ShardedJedisPool pool = new ShardedJedisPool(new JedisPoolConfig(), shards);ShardedJedis one = pool.getResource();ShardedJedisPipeline pipeline = one.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("sppn" + i, "n" + i);}List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();pool.returnResource(one);System.out.println("Pipelined@Pool SET: " + ((end - start)/1000.0) + " seconds");pool.destroy();
    }
    

    九、需要注意的地方

    1. 事务和管道都是异步模式。在事务和管道中不能同步查询结果。比如下面两个调用，都是不允许的：

        Transaction tx = jedis.multi();for (int i = 0; i < 100000; i++) {tx.set("t" + i, "t" + i);}System.out.println(tx.get("t1000").get());  //不允许List<Object> results = tx.exec();……Pipeline pipeline = jedis.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("p" + i, "p" + i);}System.out.println(pipeline.get("p1000").get()); //不允许List<Object> results = pipeline.syncAndReturnAll();
       

    2. 事务和管道都是异步的，个人感觉，在管道中再进行事务调用，没有必要，不如直接进行事务模式。

    3. 分布式中，连接池的性能比直连的性能略好(见后续测试部分)。

    4. 分布式调用中不支持事务。

       因为事务是在服务器端实现，而在分布式中，每批次的调用对象都可能访问不同的机器，所以，没法进行事务。

    十、测试

    运行上面的代码，进行测试，其结果如下：

    Simple SET: 5.227 secondsTransaction SET: 0.5 seconds
    Pipelined SET: 0.353 seconds
    Pipelined transaction: 0.509 secondsSimple@Sharing SET: 5.289 seconds
    Pipelined@Sharing SET: 0.348 secondsSimple@Pool SET: 5.039 seconds
    Pipelined@Pool SET: 0.401 seconds
    

    另外，经测试分布式中用到的机器越多，调用会越慢。上面是2片，下面是5片：

    Simple@Sharing SET: 5.494 seconds
    Pipelined@Sharing SET: 0.51 seconds
    Simple@Pool SET: 5.223 seconds
    Pipelined@Pool SET: 0.518 seconds
    

    下面是10片：

    Simple@Sharing SET: 5.9 seconds
    Pipelined@Sharing SET: 0.794 seconds
    Simple@Pool SET: 5.624 seconds
    Pipelined@Pool SET: 0.762 seconds
    

    下面是100片：

    Simple@Sharing SET: 14.055 seconds
    Pipelined@Sharing SET: 8.185 seconds
    Simple@Pool SET: 13.29 seconds
    Pipelined@Pool SET: 7.767 seconds
    

    分布式中，连接池方式调用不但线程安全外，根据上面的测试数据，也可以看出连接池比直连的效率更好。

    十一、完整的测试代码

    package com.example.nosqlclient;import java.util.Arrays;
    import java.util.List;import org.junit.AfterClass;
    import org.junit.BeforeClass;
    import org.junit.Test;import redis.clients.jedis.Jedis;
    import redis.clients.jedis.JedisPoolConfig;
    import redis.clients.jedis.JedisShardInfo;
    import redis.clients.jedis.Pipeline;
    import redis.clients.jedis.ShardedJedis;
    import redis.clients.jedis.ShardedJedisPipeline;
    import redis.clients.jedis.ShardedJedisPool;
    import redis.clients.jedis.Transaction;import org.junit.FixMethodOrder;
    import org.junit.runners.MethodSorters;@FixMethodOrder(MethodSorters.NAME_ASCENDING)
    public class TestJedis {private static Jedis jedis;private static ShardedJedis sharding;private static ShardedJedisPool pool;@BeforeClasspublic static void setUpBeforeClass() throws Exception {List<JedisShardInfo> shards = Arrays.asList(new JedisShardInfo("localhost",6379),new JedisShardInfo("localhost",6379)); //使用相同的ip:port,仅作测试jedis = new Jedis("localhost"); sharding = new ShardedJedis(shards);pool = new ShardedJedisPool(new JedisPoolConfig(), shards);}@AfterClasspublic static void tearDownAfterClass() throws Exception {jedis.disconnect();sharding.disconnect();pool.destroy();}@Testpublic void test1Normal() {long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {String result = jedis.set("n" + i, "n" + i);}long end = System.currentTimeMillis();System.out.println("Simple SET: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test2Trans() {long start = System.currentTimeMillis();Transaction tx = jedis.multi();for (int i = 0; i < 100000; i++) {tx.set("t" + i, "t" + i);}//System.out.println(tx.get("t1000").get());List<Object> results = tx.exec();long end = System.currentTimeMillis();System.out.println("Transaction SET: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test3Pipelined() {Pipeline pipeline = jedis.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("p" + i, "p" + i);}//System.out.println(pipeline.get("p1000").get());List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();System.out.println("Pipelined SET: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test4combPipelineTrans() {long start = System.currentTimeMillis();Pipeline pipeline = jedis.pipelined();pipeline.multi();for (int i = 0; i < 100000; i++) {pipeline.set("" + i, "" + i);}pipeline.exec();List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();System.out.println("Pipelined transaction: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test5shardNormal() {long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {String result = sharding.set("sn" + i, "n" + i);}long end = System.currentTimeMillis();System.out.println("Simple@Sharing SET: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test6shardpipelined() {ShardedJedisPipeline pipeline = sharding.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("sp" + i, "p" + i);}List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();System.out.println("Pipelined@Sharing SET: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test7shardSimplePool() {ShardedJedis one = pool.getResource();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {String result = one.set("spn" + i, "n" + i);}long end = System.currentTimeMillis();pool.returnResource(one);System.out.println("Simple@Pool SET: " + ((end - start)/1000.0) + " seconds");}@Testpublic void test8shardPipelinedPool() {ShardedJedis one = pool.getResource();ShardedJedisPipeline pipeline = one.pipelined();long start = System.currentTimeMillis();for (int i = 0; i < 100000; i++) {pipeline.set("sppn" + i, "n" + i);}List<Object> results = pipeline.syncAndReturnAll();long end = System.currentTimeMillis();pool.returnResource(one);System.out.println("Pipelined@Pool SET: " + ((end - start)/1000.0) + " seconds");}
    }