2、启动&&停止
1) 数据库字符集设置,修改mysql配置文件/etc/my.cnf中加入default-character-set=utf8
2) 启动mysql服务：service mysqld start或者/etc/init.d/mysqld start
3) 开机启动：chkconfig -add mysqld，查看开机启动设置是否成功chkconfig --list | grep mysql*
4) 停止：service mysqld stop
3、登录
1) 创建root管理员：mysqladmin -u root password 123456
2) 登录：mysql -u root -p输入密码即可。
3) 忘记密码：service mysqld stop
#mysqld_safe --user=root --skip-grant-tables
#mysql -u root
>use mysql
>update user set password=password("new_pass") where user="root";
>flush privileges;
4、远程访问
1)开放防火墙的端口号
2) mysql增加权限：mysql库中的user表新增一条记录host为“%”，user为“root”，或者将host为localhost的user改为host是"%"
5. 当service mysql start启动服务时，如果遇到“mysql: unrecognized service”，可以按以下步骤来执行：
1) rpm -q mysql查看mysql是否安装成功
2) 试用/etc/rc.d/init.d/mysqld start 看是否可以启动
3) 如果按上面步骤可启动，执行 chmod 755 /etc/rc.d/init.d/mysqld 修改权限
4) 再运行service mysql start
5) 可以设置为开机启动chkconfig mysqld on
二 安装memcached
1. memcached是基于libevent的事件处理，所以安装memcached时先要安装libevent库，首先yum list libevent-devel看看是否已有libevent-devel，若无则yum -y install libevent libevent-devel;
2. 获取安装包：
1）wget http://memcached.googlecode.com/files/memcached-1.4.4.tar.gz
2）tar -zxvf memcached-1.4.4.tar.gz
3）cd memcached-1.4.4
4）./configure
5）make && make install
3.memcached启动：
以daemon方式启动：/usr/local/bin/memcached -u nobody -p 11211 -m 64 -c 128 -d
tips:memcached常用参数：（/usr/local/bin/memcached -h）
//保存
set good 32 0 10
helloworld
STORED
//取回
gets good
VALUE good 32 10 10
helloworld
END
//替换
replace good 32 0 10
worldhello
STORED
get good
VALUE good 32 10
worldhello
END
//尾部添加
append good 32 0 5
after
STORED
get good
VALUE good 32 15
worldhelloafter
END
//头部添加
prepend good 32 0 6
before
STORED
get good
VALUE good 32 21
beforeworldhelloafter
END
//删除
delete good
DELETED
get good
END
delete good
NOT_FOUND
cas good 32 0 10 hel
helloworld
EXISTS
gets good
VALUE good 32 10 10
helloworld
END
cas bad 32 0 10 good
worldhello
NOT_FOUND
//统计
stats items
STAT items:1:number 1
STAT items:1:age 24
STAT items:1:evicted 0
STAT items:1:outofmemory 0
END
stats sizes
96 1
END
stats slabs
STAT 1:chunk_size 88
STAT 1:chunks_per_page 11915
STAT 1:total_pages 1
STAT 1:total_chunks 11915
STAT 1:used_chunks 11914
STAT 1:free_chunks 1
STAT 1:free_chunks_end 11913
STAT 2:chunk_size 112
STAT 2:chunks_per_page 9362
STAT 2:total_pages 1
STAT 2:total_chunks 9362
STAT 2:used_chunks 9361
STAT 2:free_chunks 1
STAT 2:free_chunks_end 9361
STAT 5:chunk_size 232
STAT 5:chunks_per_page 4519
STAT 5:total_pages 1
STAT 5:total_chunks 4519
STAT 5:used_chunks 4518
STAT 5:free_chunks 1
STAT 5:free_chunks_end 4518
STAT active_slabs 3
STAT total_malloced 3145472
END
stats items
STAT items:1:number 1
STAT items:1:age 1768
STAT items:1:evicted 0
STAT items:1:outofmemory 0
END
stats
STAT pid 18261
STAT uptime 528593
STAT time 1237277383
STAT version 1.2.6
STAT pointer_size 32
STAT rusage_user 0.004999
STAT rusage_system 0.015997
STAT curr_items 1
STAT total_items 2
STAT bytes 66
STAT curr_connections 2
STAT total_connections 13
STAT connection_structures 3
STAT cmd_get 11
STAT cmd_set 8
STAT get_hits 2
STAT get_misses 9
STAT evictions 0
STAT bytes_read 1342
STAT bytes_written 8752
STAT limit_maxbytes 134217728
STAT threads 1
END
使用usr/bin/perl /root/memcached-1.2.6/scripts/memcached-tool localhost:11211
output
# Item_Size Max_age 1MB_pages Count Full?
1 88 B 1531 s 1 1 no
2 112 B 0 s 1 0 no
5 232 B 0 s 1 0 no
# slab class编号
Item_Size Chunk大小
Max_age LRU内最旧的记录的生存时间
1MB_pages 分配给Slab的页数
Count Slab内的记录数
Full? Slab内是否含有空闲chunk