学步园

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1，安装libeventhttps://github.com/downloads/libevent/libevent/libevent-2.0.18-stable.tar.gz
2，安装BerkeleyDBwget http://download.oracle.com/otn/berkeley-db/db-6.0.20.tar.gz

或者http://download.huihoo.com/berkeleydb/bdb/
http://wiki.huihoo.com/index.php?title=Berkeley_DB#Linux.E7.8E.AF.E5.A2.83.E4.B8.8B.E5.AE.89.E8.A3.85
tar zxvf db-5.2.36.tar.gz

cd build_unix

../dist/configure --prefie=/usr/local/db6.0.20makesudo make install
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3，安装Memcacheqhttps://code.google.com/p/memcacheq/downloads/list

注意指定：--with-bdb=/usr/local/db6.0.20 

./configure --prefix=/usr/local/memcacheq --enable-threads --with-bdb=/usr/local/db6.0.20

make 

sudo make install

error while loading shared libraries: libdb-6.0.so: cannot open shared object file: No such file or directory

sudo ln -s /usr/local/db6.0.20/lib/libdb-6.0.so  /usr/lib/libdb-6.0.so
一，memcacheq的使用：

①，当使用set命令时，就向指定的消息队列中写入了一条新消息，也就是向BerkeleyDB中新insert了一条数据；

②，当使用get命令时，就从 指定队列中取出一条新消息，也就是向BerkeleyDB中delete了一条数据，这个时候再去get的话就返回空了，队列里没消息；

③，可以通过：stats,stats queue来查看。

hadoop@hadoopslave1:~/bigdata/hbase/bin$ telnet 172.16.201.170 11212

Trying 172.16.201.170...

Connected to 172.16.201.170.

Escape character is '^]'.

stats

STAT pid 31183

STAT uptime 605

STAT time 1372580856

STAT version 0.2.0

STAT pointer_size 64

STAT rusage_user 0.076004

STAT rusage_system 0.892055

STAT curr_connections 6

STAT total_connections 9

STAT connection_structures 7

STAT get_cmds 4

STAT get_hits 1

STAT set_cmds 1

STAT set_hits 1

STAT bytes_read 415

STAT bytes_written 2870

STAT threads 4

END

stats queue

STAT q4 1/1

END

set q  0 0 5

hhhhh

STORED

set qq 0 0 5

qqqqq

STORED

stats 

STAT pid 31183

STAT uptime 661

STAT time 1372580912

STAT version 0.2.0

STAT pointer_size 64

STAT rusage_user 0.080005

STAT rusage_system 0.908056

STAT curr_connections 6

STAT total_connections 9

STAT connection_structures 7

STAT get_cmds 4

STAT get_hits 1

STAT set_cmds 3

STAT set_hits 3

STAT bytes_read 478

STAT bytes_written 3273

STAT threads 4

END

stats queue

STAT q 1/0

STAT qq 1/0

STAT q4 1/1

END

get qq

VALUE qq 0 5

qqqqq

END

stats queue

STAT q 1/0

STAT qq 1/1

STAT q4 1/1

END

stats queue

STAT q 1/0

STAT qq 1/1

STAT q4 1/1

END

get q

VALUE q 0 5

hhhhh

END

stats queue

STAT q 1/1

STAT qq 1/1

STAT q4 1/1

END

get q

END

get qq

END 

二，Ubuntu下安装Memcached

1，安装libevent

wget http://www.monkey.org/~provos/libevent-2.0.13-stable.tar.gz

tar xzvf  libevent-2.0.13-stable.tar.gz

./configure

make

sudo make install

2,安装memcached

wget http://memcached.googlecode.com/files/memcached-1.4.7.tar.gz

tar xvzf memcached-1.4.7.tar.gz 

cd memcached-1.4.7

./configure --prefix=/usr/local/memcached/

make

make install

有时需要创建软链接

ln -s /usr/local/lib/libevent-2.0.so.5 /lib/libevent-2.0.so.5

memcached的启动

./memcached -d -m 2048 -l 10.0.0.40 -p 11211

-d 守护进程的方式启动

内存设置-------------------

-m 制定内存

-M 内存不够是禁止LRU，报错

-n 48 初始化chuck=key+suffix+value+32结构体，默认48字节

-f 增长银子，默认1.25

-L 启动大内存页，可以降低内存浪费，改进性能

链接设置------------------

-l 服务器名

-p TCP端口号，默认11211

-U UDP端口 默认11211

-c 设置最大并发的线程数

-t 线程数 默认4，由于memcached采用NIO，过多线程作用不大

-P 保存memcached的pid文件

-C 禁止使用那个CAS命令，可以禁止版本计数，减少开销

-R 每个event连接最大并发数，默认20

-h 显示帮助

连接到memcached服务器

telnet localhost 11211/telnet localhost 11211

stats

／shell＆

echo stats | nc localhost 11211

watch "echo stats | nc 192.168.1.123 11200" (实时状态)

STAT pid 22021

STAT uptime 78

STAT time 1366042693

STAT version 1.4.7

STAT libevent 2.0.13-stable

STAT pointer_size 32

STAT rusage_user 0.000000

STAT rusage_system 0.000000

----------连接数是否太多--------------------

STAT curr_connections 5

------open连接数量

STAT total_connections 6

-----服务器运行以来接受的连接总数

----------------------------

STAT connection_structures 6

STAT cmd_get 0

----取回请求总数

STAT cmd_set 0

----存储请求总数

STAT cmd_flush 0

----------命中率+STAT cmd_get 0

-------------

STAT get_hits 0

---------请求成功的总次数

STAT get_misses 0

-------请求失败的总次数

-------------------------------------------

STAT delete_misses 0

STAT delete_hits 0

STAT incr_misses 0

STAT incr_hits 0

STAT decr_misses 0

STAT decr_hits 0

STAT cas_misses 0

STAT cas_hits 0

STAT cas_badval 0

STAT auth_cmds 0

STAT auth_errors 0

STAT bytes_read 7

------------服务器从网络读取到的总字节数

STAT bytes_written 0

---------服务器向网络发送的总字节

STAT limit_maxbytes 2147483648

STAT accepting_conns 1

STAT listen_disabled_num 0

STAT threads 4

STAT conn_yields 0

STAT bytes 0

STAT curr_items 0

STAT total_items 0

STAT evictions 0

STAT reclaimed 0

<command> <key> <flags> <expiretime> <bytes> [version]

- <flags> 是在取回内容时，与数据和发送块一同保存服务器上的任意16位无符号整形（用十进制来书写）。客户端可以用它作为“位域”来存储一些特定的信息；它对服务器是不透明的。

<expiretime> 0表示永远，《30天60＊60＊24＊30》

<bytes> value的字节数

<command name> is "set", "add" or "replace"

set 意思是 “储存此数据” 

add 意思是 “储存此数据，只在服务器*未*保留此键值的数据时” （key不存在是保存）

replace意思是 “储存此数据，只在服务器*曾*保留此键值的数据时”

（key存在时replace）

"set" means "store this data". 

"add" means "store this data, but only if the server *doesn't* already

hold data for this key". 

"replace" means "store this data, but only if the server *does*

already hold data for this key".

set 无论如何都进行存储

add 只有key不存在时进行添加

repalce 只有数据存在时进行替换

cas操作，means:check and set 只有版本号相匹配是才能存取，否则返回EXISTS

目的：多客户端并发修改同一条记录的问题，防止使用改变了的key/valuee对

status slabs 区块数据统计

stats slabs

STAT 1:chunk_size 80

STAT 1:chunks_per_page 13107

STAT 1:total_pages 1

STAT 1:total_chunks 13107

STAT 1:used_chunks 2

STAT 1:free_chunks 1

STAT 1:free_chunks_end 13104

STAT 1:mem_requested 111

STAT 1:get_hits 4

STAT 1:cmd_set 6

STAT 1:delete_hits 0

STAT 1:incr_hits 0

STAT 1:decr_hits 0

STAT 1:cas_hits 0

STAT 1:cas_badval 0

STAT active_slabs 1

STAT total_malloced 1048560

stats settings 设置查看

stats settings

STAT maxbytes 2147483648

STAT maxconns 1024

STAT tcpport 11211

STAT udpport 11211

STAT inter 127.0.0.1

STAT verbosity 0

STAT oldest 0

STAT evictions on

STAT domain_socket NULL

STAT umask 700

STAT growth_factor 1.25

STAT chunk_size 48

STAT num_threads 4

STAT num_threads_per_udp 4

STAT stat_key_prefix :

STAT detail_enabled no

STAT reqs_per_event 20

STAT cas_enabled yes

STAT tcp_backlog 1024

STAT binding_protocol auto-negotiate

STAT auth_enabled_sasl no

STAT item_size_max 1048576

stats items

数据项统计

stats items

STAT items:1:number 2

STAT items:1:age 13982

STAT items:1:evicted 0

STAT items:1:evicted_nonzero 0

STAT items:1:evicted_time 0

STAT items:1:outofmemory 0

STAT items:1:tailrepairs 0

STAT items:1:reclaimed 0

END

stats sizes

对象数据统计

stats sizes

STAT 64 2

END

／／／／／／／／／／／／／

注意点

1，必须长度适合才可以存取<bytes>

2，set 存取

3，add只能添加不存在的key

4，replace只能操作存在的key

5, gets版本书+1

6，cas check and set 多客户端并发 

版本号匹配才可以存取

set mc 12 0 9

memcached

STORED

get mc

VALUE mc 12 9

memcached

END

add mc 12 0 9

hadooperr

NOT_STORED

get mc

VALUE mc 12 9

memcached

END

repalace mc 12 0 9 

ERROR

get mc   

VALUE mc 12 9

memcached

END

replace mc 12 0 9 

memcachef

STORED

get mc

VALUE mc 12 9

memcachef

END

replace kkk 0 0 5

mmmmm 

NOT_STORED

gets mc

VALUE mc 12 9 5

memcachef

END

get mc

VALUE mc 12 9

memcachef

END

gets mc

VALUE mc 12 9 5

memcachef

END

replace mc 12 0 9

memcacheg

STORED

get mc

VALUE mc 12 9

memcacheg

END

gets mc

VALUE mc 12 9 6

memcacheg

END

cas mc 21 0 9 6

gets mc

STORED

gets mc

VALUE mc 21 9 7

gets mc

END

---只有版本号匹配才可以存取，否则EXISTS

cas mc 12 0 9 6

memcaches

EXISTS

gets mc

VALUE mc 21 9 7

gets mc
END


打算在看看UC的UCMQ:
https://github.com/ucweb/ucmq