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 {

public
static
void
Main(string[]
args) {

//---------------------

//
Setting up a client.

//---------------------

Console.Out.WriteLine("Setting
up Memcached Client.");

MemcachedClient.Setup("MyCache",
new
string[]
{ "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",
new
string[]{
"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",
new
string[]{"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")
as
string;

if
(str !=
null)
{

Console.Out.WriteLine("Fetched
item with key: mystring, value: "
+
str);

}

//Get
an object

string[]
array =
cache.Get("myarray")
as
string[];

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(new
string[]{"myinteger",
"mydate"});

if
(result[0]
!=
null
&&
result[0]
is
int)
{

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)
as
string;

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) as
string;

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）。