memcache入门

初步了解

        通过https://www.cnblogs.com/xrq730/p/4948707.html这个文章对memcache做了简单了解

        官网wiki内容感觉有点太笼统，没看懂

本地安装

        环境：mac 11.0.1

        1、官网（https://memcached.org/downloads）下载最新稳定版本 memcached-1.6.9.tar.gz

        2、解压到指定目录（/app/memcached-1.6.9）参考（https://github.com/memcached/memcached/wiki/Install）中的安装过程进行安装；

cd memcached-1.x.x
./configure --prefix=/usr/local/memcached
make && make test && sudo make install

异常情况

        1、执行  ./configure --prefix=/usr/local/memcached  命令时提示：

checking for libevent directory... configure: error: libevent is required.  You can get it from https://www.monkey.org/~provos/libevent/

      If it's already installed, specify its path using --with-libevent=/dir/

        1.1、安装libevent：官网（https://libevent.org/）下载稳定版本：libevent-2.1.12-stable.tar.gz

        1.2、解压到指定目录（/app/libevent-2.1.12-stable），进入解压目录（/app/libevent-2.1.12-stable），参考（https://github.com/libevent/libevent）中的安装过程进行安装；

$ ./configure
$ make
$ make verify   # (optional)
$ sudo make install

        ./configure 过成中提示

checking for openssl/ssl.h... no
configure: error: openssl is a must but can not be found. You should add the directory containing `openssl.pc' to the `PKG_CONFIG_PATH' environment variable, or set `CFLAGS' and `LDFLAGS' directly for openssl, or use `--disable-openssl' to disable support for openssl encryption

        安装openssl然后重新执行安装命令，安装成功后可以在/usr/local/lib目录下看到libevent相关文件

        1.3、安装openssl，下载openssl（git clone git://git.openssl.org/openssl.git），进入下载目录（/app/openssl）

        1.4、执行安装命令

./Configure
make
make test
sudo make install

入门命令

        https://www.runoob.com/memcached/memcached-get-data.html

        启动命令：./memcached -d 

        帮助命令：./memcached -h

        输出日志：./memcached -d -vv >> /tmp/memcached.log 2>&1

        连接memcache:  telnet localhost 11211    （telnet 连接之后可以执行 set、get、stats等命令）

Java代码demo

        使用开源memcache客户端：https://github.com/gwhalin/Memcached-Java-Client/

import com.whalin.MemCached.MemCachedClient;
import com.whalin.MemCached.SockIOPool;

public class MemcacheTest {

    public static void main(String[] args) {
        get("p");
    }

    private static void get(String key) {
        SockIOPool pool = SockIOPool.getInstance();
        pool.setServers(new String[]{"localhost:11211"});
        pool.initialize();
        MemCachedClient memCachedClient = new MemCachedClient();
//        memCachedClient.set(key, "hello world");
        Object o = memCachedClient.get(key);
        if (o != null) {
            System.out.println(o.toString());
        } else {
            System.out.println(key + "= null");
        }
    }
}

        maven 依赖：

<dependency>
    <groupId>com.whalin</groupId>
    <artifactId>Memcached-Java-Client</artifactId>
    <version>3.0.2</version>
</dependency>

性能测试

        本地环境默认参数设置的情况下：./memcache -d

        读写速度约为5w/s

        total 参数设置为 100w，执行时间约为20s

import com.whalin.MemCached.MemCachedClient;
import com.whalin.MemCached.SockIOPool;

import java.util.UUID;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

private static void batchTest(int total) {
    SockIOPool pool = SockIOPool.getInstance();
    pool.setServers(new String[]{"localhost:11211"});
    pool.setMaxConn(1000);
    pool.setMinConn(20);
    pool.initialize();

    long start = System.currentTimeMillis();
    CountDownLatch countDown = new CountDownLatch(total);

    ExecutorService es = Executors.newFixedThreadPool(1000);
    for (int i = 0; i < total; i++) {
        es.submit(new Runnable() {
            @Override
            public void run() {
                try {
                    MemCachedClient memCachedClient = new MemCachedClient();
                    Object o = memCachedClient.get(UUID.randomUUID().toString());
//                  System.out.println("执行结果=" + b);
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    countDown.countDown();
                }
               
            });
        }
        while (countDown.getCount() > 0) {
            try {
                TimeUnit.MILLISECONDS.sleep(100);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        long end = System.currentTimeMillis();
        System.out.println("执行使用时间：" + (end - start));
        es.shutdown();
    }
}

待确认内容

        flags 参数含义