memcache/memcached/memcachedb 配置、安装<转>

当你听到memcache与memcached时把它当做是一个东东就好了，尽管它们存在区别，但是这并不影响你对它们的运用及理解。

“Memcache”它是一个自由和开放源代码、高性能、分配的内存对象缓存系统，即该系统名称为“Memcache”;

“Memcached”它是该系统的主程序文件，以守护程序方式运行于一个或多个服务器中（分布式），随时接受客户端的连接操作，使用共享内存存取数据;

“Memcachedb”它是新浪2007年的项目，在Memcached的基础上开发出来了，它与Memcache不同的是它提供了数据持久化存储

 

首先，我们需要下载一个memcached安装程序，memcached版本很多，开源的东西我们一定要找一个持续更新的版本，很简单，有团队在维护升级。

我选择的版本是：beitmemcached，项目地址：http://code.google.com/p/beitmemcached/  注：此链结为windows下memcached文程序安装文件及示例。

图中的两个文件分别为：上面的是客户端调用示例项目文件、下面的文件是Memcached主程序安装文件

 

然后，将memcached主程序文件安装到服务器上。

Windows下安装：

1.将上图中Memcached 1.2.5.zip解压缩到 D:\program files\memcached目录下（此目录自行定义）。

2.Ctrl+R，输入cmd，打开命令行窗口，转到D:\program files\memcached目录下。

3.memcached.exe -d install

4.memcached.exe -d start

如果你要卸载，执行下面的命令：

1.memcached.exe -d stop

2.memcached.exe -d uninstall

Linux（CentOS 5.x）下安装：

1. yum install gcc 

2. cd /tmp

3. wget http://www.monkey.org/~provos/libevent-2.0.4-alpha.tar.gz   注：memcached 用到了 libevent 这个库用于 Socket 的处理，所以 还需要安装 libevent

4. tar zxvf libevent-2.0.4-alpha.tar.gz

5. cd libevent-2.0.4-alpha

6. ./configure -prefix=/usr/local/libevent

7. make

8. make install

9. cd ~

10. cd /tmp

11. http://memcached.googlecode.com/files/memcached-1.4.5.tar.gz

12. tar zxvf memcached-1.4.5.tar.gz

13. cd memcached-1.4.5

14. ./configure -prefix=/usr/local/memcached --with-libevent=/usr/local/libevent    注：安装memcached时需要指定libevent的安装位置

15. make

16. make install

17. export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/libevent/lib   注：将libevent的lib目录加入LD_LIBRARY_PATH里

18. vi /etc/sysconfig/iptables 

19. 将下面这行加入进去

-A RH-Firewall-l-INPUT -p tcp -m tcp --dport 11211 -j ACCEPT  注：将memcached加入到防火墙允许访问规则中

20. service iptables restart  注：防火墙重启

21. /usr/local/memcached/bin/memcached -d   注：启动memcached

 

memcached启动参数描述：

-d ：启动一个守护进程，

-m：分配给Memcache使用的内存数量，单位是MB，默认是64MB，

-u ：运行Memcache的用户

-l  ：监听的服务器IP地址

-p ：设置Memcache监听的端口，默认是11211    注：-p（p为小写）

-c ：设置最大并发连接数，默认是1024

-P ：设置保存Memcache的pid文件   注：-P（P为大写）

如果要结束Memcache进程，执行：kill cat pid文件路径

 

无论是在windows下还是在linux下安装都非常简单，使用起来也很简单。

如何往memcached中插入数据？如何来读取数据？示例代码如下：

using System;
using System.Collections.Generic;

namespace BeIT.MemCached {
class Example {
publicstaticvoid Main(string[] args) {
//---------------------
// Setting up a client.
//---------------------
Console.Out.WriteLine("Setting up Memcached Client.");
MemcachedClient.Setup("MyCache",newstring[] { "localhost" });

//It is possible to have several clients with different configurations:
//If it is impossible to resolve the hosts, this method will throw an exception.
try {
MemcachedClient.Setup("MyOtherCache",newstring[]{"server1.example.com:12345","server2.example.com:12345"});
} catch (Exception e) {
Console.WriteLine(e.Message);
}

//Get the instance we just set up so we can use it. You can either store this reference yourself in
//some field, or fetch it every time you need it, it doesn't really matter.
MemcachedClient cache= MemcachedClient.GetInstance("MyCache");

//It is also possible to set up clients in the standard config file. Check the section "beitmemcached"
//in the App.config file in this project and you will see that a client called "MyConfigFileCache" is defined.
MemcachedClient configFileCache= MemcachedClient.GetInstance("MyConfigFileCache");

//Change client settings to values other than the default like this:
cache.SendReceiveTimeout=5000;
cache.ConnectTimeout =5000;
cache.MinPoolSize =1;
cache.MaxPoolSize =5;

//----------------
// Using a client.
//----------------

//Set some items
Console.Out.WriteLine("Storing some items.");
cache.Set("mystring","The quick brown fox jumped over the lazy dog.");
cache.Set("myarray",newstring[]{"This is the first string.","This is the second string."});
cache.Set("myinteger",4711);
cache.Set("mydate",new DateTime(2008,02,23));
//Use custom hash
cache.Set("secondstring","Flygande b鋍kasiner s鰇a hwila p?mjuka tufvor",4711);

//Get a string
string str = cache.Get("mystring")asstring;
if (str !=null) {
Console.Out.WriteLine("Fetched item with key: mystring, value: "+ str);
}

//Get an object
string[] array = cache.Get("myarray")asstring[];
if (array !=null) {
Console.Out.WriteLine("Fetched items with key: myarray, value 1: "+ array[0]+", value 2: "+ array[1]);
}

//Get several values at once
object[] result = cache.Get(newstring[]{"myinteger","mydate"});
if (result[0]!=null&& result[0]isint) {
Console.Out.WriteLine("Fetched item with key: myinteger, value: "+ (int)result[0]);
}
if (result[1]!=null&& result[1]is DateTime) {
Console.Out.WriteLine("Fetched item with key: mydate, value: "+ (DateTime)result[1]);
}

str = cache.Get("secondstring",4711)asstring;
if (str !=null) {
Console.Out.WriteLine("Fetched item with key and custom hash: secondstring, value: "+ str);
}

//Set a counter
Console.Out.WriteLine("Setting an item for incrementing and decrementing.");
cache.SetCounter("mycounter",9000);
ulong? counter = cache.GetCounter("mycounter");
if (counter.HasValue) {
Console.Out.WriteLine("Fetched mycounter, value: "+ counter.Value);
}

//Increment the counter
counter= cache.Increment("mycounter",1);
if (counter.HasValue) {
Console.Out.WriteLine("Incremented mycounter with 1, new value: "+ counter.Value);
}

//Decrement the counter
counter= cache.Decrement("mycounter",9000);
if (counter.HasValue) {
Console.Out.WriteLine("Decremented mycounter with 9000, new value: "+ counter.Value);
}

//Append and prepend
Console.Out.WriteLine("Storing bar for append/prepend");
cache.Set("foo","bar");
Console.Out.WriteLine("Appending baz");
cache.Append("foo"," baz");
Console.Out.WriteLine("Prepending foo");
cache.Prepend("foo","foo");
Console.Out.WriteLine("New value: "+ cache.Get("foo"));

//Cas
cache.Delete("castest");
Console.Out.WriteLine("Trying to CAS non-existant key castest: "+ cache.CheckAndSet("castest","a",0));
Console.Out.WriteLine("Setting value for key: castest, value: a");
cache.Set("castest","a");
Console.Out.WriteLine("Trying to CAS key castest with the wrong unique: "+ cache.CheckAndSet("castest","a",0));
ulong unique;
cache.Gets("castest",out unique);
Console.Out.WriteLine("Getting cas unique for key castest: "+ unique);
Console.Out.WriteLine("Trying to CAS again with the above unique: "+ cache.CheckAndSet("castest","b", unique));
string value = cache.Gets("castest",out unique) asstring;
Console.Out.WriteLine("New value: "+ value +", new unique: "+ unique);

Console.Out.WriteLine("Displaying the socketpool status:");
foreach (KeyValuePair<string, Dictionary<string,string>> host in cache.Status()) {
Console.Out.WriteLine("Host:"+ host.Key);
foreach (KeyValuePair<string,string> item in host.Value) {
Console.Out.WriteLine("\t"+ item.Key +":"+ item.Value);
}
Console.Out.WriteLine();
}

Console.Out.WriteLine();
Console.Out.WriteLine("Finished. Press enter to exit.");
Console.In.ReadLine();
}
}
}

注：memcached是以KEY-VALUE的方式进行数据存储的，KEY的大小限制：Key（max）<=250个字符；VALUE在存储时有限制：Value（max）<= 1M；memcached默认过期时间：ExpiresTime（max）= 30（days）。