xmemcached 客户端使用

1. 最近调研了下memcached，之前2篇博客简单得介绍了用法，现在做个总结就当调研结束，本博客将从以下几个方面进行总结，

a. xmemcached简介

b. xmemcached的分布式

c. xmemcached支持的存储对象

d. xmemcached的容错性

e. xmemcached的性能测试

    由于memcached可以与spring集成，所以本博客以和spring集成来讲以上几点

先来看看如何与spring集成，首先在pom中引入相应的包(spring相关的不列出来)

<dependency>
            <groupId>com.googlecode.xmemcached</groupId>
            <artifactId>xmemcached</artifactId>
            <version>2.0.0</version>
        </dependency>

以下是properties文件：

# the pool size(the number of client)
memcached.connectionPoolSize=50
# in this mode, when a node out, it will throws MemcachedException when call this node
memcached.failureMode=true
#server1
memcached.server1.host=192.168.88.140
memcached.server1.port=11211
memcached.server1.weight=1
#server2
memcached.server2.host=192.168.88.141
memcached.server2.port=11211
memcached.server2.weight=1
#server3
memcached.server3.host=192.168.88.142
memcached.server3.port=11211
memcached.server3.weight=1

spring bean配置：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:p="http://www.springframework.org/schema/p" xmlns:c="http://www.springframework.org/schema/c"
    xmlns:rabbit="http://www.springframework.org/schema/rabbit" xmlns:task="http://www.springframework.org/schema/task"
    xsi:schemaLocation="http://www.springframework.org/schema/beans
                        http://www.springframework.org/schema/beans/spring-beans.xsd
                        http://www.springframework.org/schema/context
                        http://www.springframework.org/schema/context/spring-context.xsd
                        http://www.springframework.org/schema/rabbit
                        http://www.springframework.org/schema/rabbit/spring-rabbit-1.3.xsd
                        http://www.springframework.org/schema/task
                        http://www.springframework.org/schema/task/spring-task.xsd">

    <bean id="memcachedClientBuilder" class="net.rubyeye.xmemcached.XMemcachedClientBuilder"
        p:connectionPoolSize="${memcached.connectionPoolSize}" p:failureMode="${memcached.failureMode}">
        <!-- XMemcachedClientBuilder have two arguments.First is server list,and
            second is weights array. -->
        <constructor-arg>
            <list>
                <bean class="java.net.InetSocketAddress">
                    <constructor-arg>
                        <value>${memcached.server1.host}</value>
                    </constructor-arg>
                    <constructor-arg>
                        <value>${memcached.server1.port}</value>
                    </constructor-arg>
                </bean>
                <bean class="java.net.InetSocketAddress">
                    <constructor-arg>
                        <value>${memcached.server2.host}</value>
                    </constructor-arg>
                    <constructor-arg>
                        <value>${memcached.server2.port}</value>
                    </constructor-arg>
                </bean>
                <bean class="java.net.InetSocketAddress">
                    <constructor-arg>
                        <value>${memcached.server3.host}</value>
                    </constructor-arg>
                    <constructor-arg>
                        <value>${memcached.server3.port}</value>
                    </constructor-arg>
                </bean>
            </list>
        </constructor-arg>
        <constructor-arg>
            <list>
                <value>${memcached.server1.weight}</value>
                <value>${memcached.server2.weight}</value>
                <value>${memcached.server3.weight}</value>
            </list>
        </constructor-arg>
        <!-- BinaryCommandFactory -->
        <property name="commandFactory">
            <bean class="net.rubyeye.xmemcached.command.BinaryCommandFactory" />
        </property>
        <property name="transcoder">
            <bean class="net.rubyeye.xmemcached.transcoders.SerializingTranscoder" />
        </property>
        <property name="bufferAllocator">
            <bean class="net.rubyeye.xmemcached.buffer.SimpleBufferAllocator"></bean>
        </property>
    </bean>
    <!-- Use factory bean to build memcached client -->
    <bean id="memcachedClient" factory-bean="memcachedClientBuilder"
        factory-method="build" destroy-method="shutdown" />

</beans>

这样就可以用memcachedClient了

举个简单的例子说明如何使用：

@Autowired
    private MemcachedClient memcachedClient;

    public Map<String, User> queryFromCache(List<String> keys) {
        Map<String, User> users = new HashMap<String, User>();
        for (String key : keys) {
            try {
                User user = memcachedClient.get(key);
                users.put(key, user);
            } catch (TimeoutException e) {
                e.printStackTrace();
            } catch (InterruptedException e) {
                e.printStackTrace();
            } catch (MemcachedException e) {
                e.printStackTrace();
            }
        }
        return users;
    }

xmemcached简介

xmemcached是一个新java memcached client。简单来说，Memcached 是一个高性能的分布式内存对象的key-value缓存系统，用于动态Web应用以减轻数据库负载，现在也有很多人将它作为内存式数据库在使用，memcached通过它的自定义协议与客户端交互，而XMemcached就是它的一个java客户端实现。

Memcached的java客户端已经存在两个了：官方提供的基于传统阻塞io的客户端 、Dustin Sallings实现的基于java nio的spymemcached 。另外还有一些在此基础上的改进版本。

XMemcached的主要特性

高性能

XMemcached同样是基于java nio的客户端，java nio相比于传统阻塞io模型来说，有效率高（特别在高并发下）和资源耗费相对较少的优点。传统阻塞IO为了提高效率，需要创建一定数量的连接形成连接池，而nio仅需要一个连接即可（当然,nio也是可以做池化处理），相对来说减少了线程创建和切换的开销，这一点在高并发下特别明显。因此XMemcached与Spymemcached在性能都非常优秀，在某些方面（存储的数据比较小的情况下）Xmemcached比Spymemcached的表现更为优秀，具体可以看这个 Java Memcached Clients Benchmark 。

支持完整的协议

Xmemcached支持所有的memcached协议，包括1.4.0正式开始使用的 二进制协议 。

支持客户端分布

Memcached的分布只能通过客户端来实现，XMemcached实现了此功能，并且提供了一致性哈希(consistent hash)算法的实现。

允许设置节点权重

XMemcached允许通过设置节点的权重来调节memcached的负载，设置的权重越高，该memcached节点存储的数据将越多，所承受的负载越大。

动态增删节点

XMemcached允许通过JMX或者代码编程实现节点的动态添加或者移除，方便用户扩展和替换节点等。

支持JMX

XMemcached通过JMX暴露的一些接口，支持client本身的监控和调整，允许动态设置调优参数、查看统计数据、动态增删节点等。

xmemcached的分布式

由于memcached不支持服务器端分布式，所以m emcached的分布只能通过客户端来实现，xmemcached实现了此功能，并且提供了一致性哈希(consistent hash)算法的实现，关于一致性hashing见http://kb.cnblogs.com/page/42734/

需要说明的是这还只是客户端分布式，不支持主从，各个节点其实还是单独存储，并且未实现存储冗余，节点挂了数据就会相应得丢失

具有如下优势：

允许设置节点权重

XMemcached允许通过设置节点的权重来调节memcached的负载，设置的权重越高，该memcached节点存储的数据将越多，所承受的负载越大。

动态增删节点

XMemcached允许通过JMX或者代码编程实现节点的动态添加或者移除，方便用户扩展和替换节点等。

支持JMX

XMemcached通过JMX暴露的一些接口，支持client本身的监控和调整，允许动态设置调优参数、查看统计数据、动态增删节点等

xmemcached支持的存储对象

xmemcached支持的存储比较简单，只要实现了java序列化接口（Serializable接口）的对象就可以存储，当然可以包含Map、Set、List这些复杂对象

xmemcached的容错性

如果当前连接了3个服务器端，其中有一个突然挂掉，那么执行client操作时会抛出异常，但是如果memcached.failureMode=true设置成false那么就不抛出异常，只不过你查询的那个数据显示为null

由于是客户端分布式，所以并未实现存储冗余，如果要冗余需要自己实现代码

xmemcached的性能测试

这里有一个博客介绍了spymemcached和xmemcached的性能对比,http://www.blogjava.net/killme2008/archive/2009/03/04/257852.html

下面我自己来做一个测试

测试环境

memcached版本1.4.22

启动memcached的内存：1G

节点数：3

测试结果单位:tps

先测试简单的String，测试一共开100个线程，每个线程执行10000次操作，结果如下：

写	76062
读	91116
删	89863

再来测试复杂型的Map, 测试一共开50个线程，每个线程执行100次操作，结果如下：

写	2399
读	1901
删	13227

具体代码如下：

public class PerformanceTest {

    static class TestWriteRunnable implements Runnable {

        private MemcachedClient mc;
        private CountDownLatch cd;
        int repeat;
        int start;

        public TestWriteRunnable(MemcachedClient mc, int start, CountDownLatch cdl, int repeat) {
            super();
            this.mc = mc;
            this.start = start;
            this.cd = cdl;
            this.repeat = repeat;

        }

        public void run() {
            try {

                for (int i = 0; i < repeat; i++) {
                    String key = String.valueOf(start + i);
                    if (!mc.set(key, 0, key)) {
                        System.err.println("set error");
                    }

                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                cd.countDown();
            }
        }

    }

    static class TestReadRunnable implements Runnable {

        private MemcachedClient mc;
        private CountDownLatch cd;
        int repeat;
        int start;

        public TestReadRunnable(MemcachedClient mc, int start, CountDownLatch cdl, int repeat) {
            super();
            this.mc = mc;
            this.start = start;
            this.cd = cdl;
            this.repeat = repeat;

        }

        public void run() {
            try {
                for (int i = 0; i < repeat; i++) {

                    String key = String.valueOf(start + i);
                    String result = (String) mc.get(key);
                    if (!key.equals(result)) {
                        System.out.println(key + " " + result);
                        System.err.println("get error");
                    }
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                cd.countDown();
            }
        }

    }

    static class TestDeleteRunnable implements Runnable {

        private MemcachedClient mc;
        private CountDownLatch cd;
        int repeat;
        int start;

        public TestDeleteRunnable(MemcachedClient mc, int start, CountDownLatch cdl, int repeat) {
            super();
            this.mc = mc;
            this.start = start;
            this.cd = cdl;
            this.repeat = repeat;

        }

        public void run() {
            try {
                for (int i = 0; i < repeat; i++) {
                    String key = String.valueOf(start + i);
                    if (!mc.delete(key))
                        System.err.println("delete error");
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                cd.countDown();
            }
        }

    }

    // thread num=10, repeat=10000,size=2, all=200000 ,velocity=1057 , using
    // time:189187
    static public void main(String[] args) {
        try {
            String address = "192.168.88.140:11211 192.168.88.141:11211 192.168.88.142:11211";

            int size = Runtime.getRuntime().availableProcessors();

            int thread = 100;

            int repeat = 10000;

            MemcachedClientBuilder builder = new XMemcachedClientBuilder(AddrUtil.getAddresses(address), new int[] { 1,
                    1, 1 });
            MemcachedClient mc = null;
            builder.setConnectionPoolSize(5);
            try {
                mc = builder.build();
            } catch (IOException e) {
                e.printStackTrace();
            }
            CountDownLatch cdl = new CountDownLatch(thread);
            long t = System.currentTimeMillis();
            for (int i = 0; i < thread; i++) {
                new Thread(new PerformanceTest.TestWriteRunnable(mc, i * 10000, cdl, repeat)).start();
            }
            cdl.await();
            long all = thread * repeat;
            long usingtime = (System.currentTimeMillis() - t);

            System.out.println(String.format(
                    "test write,thread num=%d, repeat=%d,size=%d, all=%d ,velocity=%d , using time:%d", thread, repeat,
                    size, all, 1000 * all / usingtime, usingtime));

            cdl = new CountDownLatch(thread);
            t = System.currentTimeMillis();
            for (int i = 0; i < thread; i++) {
                new Thread(new PerformanceTest.TestReadRunnable(mc, i * 10000, cdl, repeat)).start();
            }
            cdl.await();
            all = thread * repeat;
            usingtime = (System.currentTimeMillis() - t);
            System.out.println(String.format(
                    "test read,thread num=%d, repeat=%d,size=%d, all=%d ,velocity=%d , using time:%d", thread, repeat,
                    size, all, 1000 * all / usingtime, usingtime));
            cdl = new CountDownLatch(thread);
            t = System.currentTimeMillis();
            for (int i = 0; i < thread; i++) {
                new Thread(new PerformanceTest.TestDeleteRunnable(mc, i * 10000, cdl, repeat)).start();
            }
            cdl.await();
            all = thread * repeat;
            usingtime = (System.currentTimeMillis() - t);
            System.out.println(String.format(
                    "test delete,thread num=%d, repeat=%d,size=%d, all=%d ,velocity=%d , using time:%d", thread,
                    repeat, size, all, 1000 * all / usingtime, usingtime));

            mc.shutdown();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

public class PerformanceTest2 {
    static Map<String, Book> map2 = new HashMap<String, Book>();
    static final int ELEMENT_NUM = 100;
    static {
        for (int i = 0; i < ELEMENT_NUM; i++)
            map2.put(String.valueOf(i), new Book(i, String.valueOf(i), String.valueOf(i)));
    }

    static class TestWriteRunnable implements Runnable {

        private MemcachedClient mc;
        private CountDownLatch cd;
        int repeat;
        int start;

        public TestWriteRunnable(MemcachedClient mc, int start, CountDownLatch cdl, int repeat) {
            super();
            this.mc = mc;
            this.start = start;
            this.cd = cdl;
            this.repeat = repeat;

        }

        public void run() {
            try {

                for (int i = 0; i < repeat; i++) {
                    String key = String.valueOf(start + i);
                    if (!mc.set(key, 0, map2)) {
                        System.err.println("set error");
                    }

                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                cd.countDown();
            }
        }

    }

    static class TestReadRunnable implements Runnable {

        private MemcachedClient mc;
        private CountDownLatch cd;
        int repeat;
        int start;

        public TestReadRunnable(MemcachedClient mc, int start, CountDownLatch cdl, int repeat) {
            super();
            this.mc = mc;
            this.start = start;
            this.cd = cdl;
            this.repeat = repeat;

        }

        @SuppressWarnings("unchecked")
        public void run() {
            try {
                for (int i = 0; i < repeat; i++) {

                    String key = String.valueOf(start + i);
                    Map<String, Book> result = (Map<String, Book>) mc.get(key);
                    if (result.size() != ELEMENT_NUM) {
                        System.err.println("get error");
                    }
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                cd.countDown();
            }
        }

    }

    static class TestDeleteRunnable implements Runnable {

        private MemcachedClient mc;
        private CountDownLatch cd;
        int repeat;
        int start;

        public TestDeleteRunnable(MemcachedClient mc, int start, CountDownLatch cdl, int repeat) {
            super();
            this.mc = mc;
            this.start = start;
            this.cd = cdl;
            this.repeat = repeat;

        }

        public void run() {
            try {
                for (int i = 0; i < repeat; i++) {
                    String key = String.valueOf(start + i);
                    if (!mc.delete(key))
                        System.err.println("delete error");
                }

            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                cd.countDown();
            }
        }

    }

    // thread num=10, repeat=10000,size=2, all=200000 ,velocity=1057 , using
    // time:189187
    static public void main(String[] args) {
        try {
            String address = "192.168.88.140:11211 192.168.88.141:11211 192.168.88.142:11211";

            int size = Runtime.getRuntime().availableProcessors();

            int thread = 50;

            int repeat = 100;

            MemcachedClientBuilder builder = new XMemcachedClientBuilder(AddrUtil.getAddresses(address), new int[] { 1,
                    1, 1 });
            MemcachedClient mc = null;
            builder.setConnectionPoolSize(5);
            try {
                mc = builder.build();
            } catch (IOException e) {
                e.printStackTrace();
            }

            CountDownLatch cdl = new CountDownLatch(thread);
            long t = System.currentTimeMillis();
            for (int i = 0; i < thread; i++) {
                new Thread(new PerformanceTest2.TestWriteRunnable(mc, i * 10000, cdl, repeat)).start();
            }
            try {
                cdl.await();
            } catch (InterruptedException e) {

            }
            long all = thread * repeat;
            long usingtime = (System.currentTimeMillis() - t);

            System.out.println(String.format(
                    "test write,thread num=%d, repeat=%d,size=%d, all=%d ,velocity=%d , using time:%d", thread, repeat,
                    size, all, 1000 * all / usingtime, usingtime));

            cdl = new CountDownLatch(thread);
            t = System.currentTimeMillis();
            for (int i = 0; i < thread; i++) {
                new Thread(new PerformanceTest2.TestReadRunnable(mc, i * 10000, cdl, repeat)).start();
            }
            try {
                cdl.await();
            } catch (InterruptedException e) {

            }
            all = thread * repeat;
            usingtime = (System.currentTimeMillis() - t);
            System.out.println(String.format(
                    "test read,thread num=%d, repeat=%d,size=%d, all=%d ,velocity=%d , using time:%d", thread, repeat,
                    size, all, 1000 * all / usingtime, usingtime));
            cdl = new CountDownLatch(thread);
            t = System.currentTimeMillis();
            for (int i = 0; i < thread; i++) {
                new Thread(new PerformanceTest2.TestDeleteRunnable(mc, i * 10000, cdl, repeat)).start();
            }
            try {
                cdl.await();
            } catch (InterruptedException e) {

            }
            all = thread * repeat;
            usingtime = (System.currentTimeMillis() - t);
            System.out.println(String.format(
                    "test delete,thread num=%d, repeat=%d,size=%d, all=%d ,velocity=%d , using time:%d", thread,
                    repeat, size, all, 1000 * all / usingtime, usingtime));

            mc.shutdown();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}