Memcached详解

PORT="11211"      # 端口，同时监听tcp和udp的11211端口，其中udp端口可以关闭
USER="memcached"  # 运行的用户名
MAXCONN="1024"    # 最大并发连接数
CACHESIZE="64"    # 内存空间大小
OPTIONS=""        # 指定额外的选项

-s <file>
        Unix socket path to listen on (disables network support).
        # 使用本地的套接字通信，基于内存共享的方式向本机提供服务
-l <ip_addr>
        Listen on <ip_addr>; default to INADDR_ANY.
        # 监听的地址，默认监听本地所有地址
-d     Run memcached as a daemon.
        # 将memcached运行为守护进程
-u <username>
        Assume the identity of <username> (only when run as root).
        # 以指定用户的身份运行memcached
-m <num>
        Use <num> MB memory max to use for object storage; the default is 64 megabytes.
        # 使用的内存空间，默认为64M
-c <num>
        Use <num> max simultaneous connections; the default is 1024.
        # 最大并发连接数，默认为1024
-p <num>
        Listen on TCP port <num>, the default is port 11211.
        # 监听的tcp端口，默认端口为11211
-U <num>
        Listen on UDP port <num>, the default is port 11211, 0 is off.
        # 监听的udp端口，默认为11211，且设置成0表示关闭
-M   Disable  automatic  removal of items from the cache when out of memory.  Additions will
        not be possible until adequate space is freed up.
        禁止使用LRU算法去清理内存
-f <factor>
        The default is 1.25.
        # 增长因子，默认为1.25
-v     Be verbose during the event loop; print out errors and warnings.
        # 显示详细信息
-vv    Be even more verbose; same as -v but also print client commands and responses.
        # 显示更详细的信息
-t <threads>
              Number of threads to use to process incoming requests. The default is 4.
        # 指明memcached提供服务的线程数，默认为4个
-B <proto>
        Specify the binding protocol to use.  By default, the server will autonegotiate  client
        connections.   By  using  this option, you can specify the protocol clients must speak.
        Possible options are  "auto"  (the  default,  autonegotiation  behavior), 
         "ascii"  and "binary".
        # 所支持的协议，有两种，ascii和binary，默认是自动选择

set mykey 0 600 5  
hello
STORED
# 表示存储一个键名为mykey的数据，存储时间为600秒，占据5个字节，存储内容为hello
# 如果显示STORED，则表明数据已经存储完成

add mykey_2 0 600 5   # 存储一个先前不存在的键值对数据
world    
STORED
add mykey_2 0 600 5   # 因为这个键已经存在了，所以无法存储成功
hello
NOT_STORED

replace mykey 0 600 3   # 将名为mykey的键的值替换为123   
123
STORED

get mykey mykey_1  # 获取mykey和mykey_1键对应的值和相关信息
VALUE mykey 0 3
123
VALUE mykey_1 0 5
hello
END

gets mykey_1
VALUE mykey_1 0 5 6
hello
END

cas mykey 0 0 3 8 
456 
EXISTS 
cas mykey 0 0 3 9 
456 
STORED

append mykey 0 0 3 
456 
STORED

prepend mykey 0 0 3 
456 
STORED

delete mykey 
DELETED

flush_all
OK

pid                     Memcached 进程ID  
uptime                  Memcached 运行时间，单位：秒  
time                    Memcached 当前的UNIX时间  
version                 Memcached 的版本号  
rusage_user             该进程累计的用户时间，单位：秒  
rusage_system           该进程累计的系统时间，单位：秒  
curr_items              Memcached 当前存储的内容数量  
total_items             Memcached 启动以来存储过的内容总数  
bytes                   Memcached 当前存储内容所占用的字节数(*/1024/1024=mb)  
curr_connections        当前连接数量  
total_connections       Memcached 运行以来接受的连接总数  
connection_structures   Memcached 分配的连接结构的数量  
cmd_get                 查询请求总数  
cmd_set                 存储（添加/更新）请求总数  
get_hits                查询成功获取数据的总次数  
get_misses              查询成功未获取到数据的总次数  
bytes_read              Memcached 从网络读取到的总字节数  
bytes_written           Memcached 向网络发送的总字节数  
limit_maxbytes          Memcached 在存储时被允许使用的字节总数  

stats items
STAT items:1:number 1
STAT items:1:age 12
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
STAT items:1:expired_unfetched 0
STAT items:1:evicted_unfetched 0
END

stats slabs
STAT 1:chunk_size 96
STAT 1:chunks_per_page 10922
STAT 1:total_pages 1
STAT 1:total_chunks 10922
STAT 1:used_chunks 1
STAT 1:free_chunks 10921
STAT 1:free_chunks_end 0
STAT 1:mem_requested 75
STAT 1:get_hits 10
STAT 1:cmd_set 10
STAT 1:delete_hits 1
STAT 1:incr_hits 0
STAT 1:decr_hits 0
STAT 1:cas_hits 0
STAT 1:cas_badval 0
STAT 1:touch_hits 0
STAT active_slabs 1
STAT total_malloced 1048512
END

stats sizes
STAT 96 1
END

stats reset
RESET