Redis 基础概念和命令

Redis 是什么

Redis是一种基于键值对(key-value)的NoSQL数据库。

为什么使用Redis

速度快

Redis的时间颗粒度一般是微秒，慢查询的默认值是10 000微秒，即10毫秒。

简单

• API
• 协议：RESP(REdis Serialization Protocol)
• 源码：5万

怎么使用Redis

命令总览

redis	mysql	作用
redis-cli	mysql	自带客户端
set	insert ... on duplicate key update	新增或者修改
get	select	查询
del	delete from	删除
client list	show processlist	查看连接情况
keys pattern	like	查询对应模式的key列表
info replication	-	是否Master节点
config get requirepass	-	查看密码
expire key seconds	-	设置key的有效期
ttl key	-	查看key的有效期
exists key	-	判断key是否存在

命令讲解

redis-cli

连接指定IP，指定端口的redis服务器

redis-cli -h {host} -p {port} -a {pass}

$./redis-cli -h 10.202.24.171 -p 8080
10.202.24.171:8080> PING
(error) NOAUTH Authentication required.
10.202.24.171:8080> AUTH admin.123
OK
10.202.24.171:8080>

./redis-cli -h 10.202.101.4 -p 6379 -a admin.123

key的增删改查

set key value

get key

del key

10.202.24.171:8080> set user_449631 lihairong
OK
10.202.24.171:8080> get user_449631
"lihairong"
10.202.24.171:8080> exists user_449631
(integer) 1
10.202.24.171:8080> del user_449631
(integer) 1
10.202.24.171:8080> get user_449631
(nil)
10.202.24.171:8080> exists user_449631
(integer) 0
10.202.24.171:8080>

查询是否master节点

10.202.24.171:8080> info Replication
# Replication
role:master
connected_slaves:0
master_repl_offset:11545465
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:10496890
repl_backlog_histlen:1048576

10.2.xxx.xx:8080> info Replication
# Replication
role:slave
master_host:10.2.231.94
master_port:8080
master_link_status:up
master_last_io_seconds_ago:0
master_sync_in_progress:0
slave_repl_offset:11661520052
slave_priority:100
slave_read_only:1
connected_slaves:0
master_repl_offset:0
repl_backlog_active:0
repl_backlog_size:1048576
repl_backlog_first_byte_offset:0
repl_backlog_histlen:0

查看pass

连接并认证可通过redis命令获取

127.0.0.1:6379> config get requirepass

查看服务器的配置文件，一般存放在conf文件夹

[appdeploy@cnsz22vl1101:/app/redis/conf]$cat SFECP_CNSZ22_REDIS_CACHE_SVR_01.conf | grep requirepass
requirepass "admin.123"

client list

10.202.24.171:8080> client list
id=8 addr=10.202.24.171:39978 fd=11 name=sentinel-ca6ff759-cmd age=11843771 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=publish
id=10 addr=10.202.24.171:30351 fd=13 name=sentinel-2aef8d79-cmd age=11843761 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=info
id=30711 addr=10.202.24.170:56322 fd=5 name=sentinel-0a0deac6-cmd age=7307073 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=publish
id=42956 addr=10.202.24.171:17510 fd=10 name=sentinel-2aef8d79-pubsub age=6629498 idle=0 flags=N db=0 sub=1 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=subscribe
id=42958 addr=10.202.24.171:59685 fd=14 name=sentinel-ca6ff759-pubsub age=6629498 idle=0 flags=N db=0 sub=1 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=subscribe
id=54850 addr=10.202.24.170:27905 fd=6 name=sentinel-0a0deac6-pubsub age=6109432 idle=0 flags=N db=0 sub=1 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=subscribe
id=161052 addr=10.202.91.7:37620 fd=7 name= age=8965 idle=3 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping
id=161055 addr=10.202.91.14:27102 fd=9 name= age=8890 idle=9 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping
id=161056 addr=10.202.91.13:35310 fd=12 name= age=8889 idle=8 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping
id=161147 addr=10.202.91.1:56217 fd=15 name= age=202 idle=5 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping
id=161151 addr=10.202.91.1:56817 fd=8 name= age=5 idle=5 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=0 obl=0 oll=0 omem=0 events=r cmd=ping
id=161152 addr=10.202.24.13:29523 fd=16 name= age=4 idle=0 flags=N db=0 sub=0 psub=0 multi=-1 qbuf=0 qbuf-free=32768 obl=0 oll=0 omem=0 events=r cmd=client

key的有效期

ttl key

10.202.24.171:8080> keys service*
1) "serviceArea_20170411"
2) "serviceArea_serviceArea"
3) "serviceArea_20170515"
10.202.24.171:8080> ttl serviceArea_20170515
(integer) 41559
10.202.24.171:8080> quit
[appdeploy@cnsz22vl1101:/app/redis/conf]$bc
bc 1.06.95
Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006 Free Software Foundation, Inc.
This is free software with ABSOLUTELY NO WARRANTY.
For details type `warranty'.
41559 / 60 /60
11
^C
(interrupt) Exiting bc.
[appdeploy@cnsz22vl1101:/app/redis/conf]$date
Mon May 15 12:25:34 CST 2017

info

配置很多，请参看扩展阅读。

缓存更新的套路

• Cache Aside Pattern

+--------------------------------------------------+
|                                                  |
|                      Web Server                  |
|                                                  |
+------------------^^--------------------^^--------+
        ||         ||                    ||
    hit ||         ||                    ||
        ||         || return             ||
        ||         ||                    ||
+-------vv---------------------+         ||
|                              |         ||
|         Cache(Redis)         |         || return
|                              |         ||
+------------------^^----------+         ||
        ||         ||                    ||
    miss||         ||                    ||
        ||         || write cache        ||
        ||         ||                    ||
+-------vv------------------------------------------+
|                                                   |
|                      DB (MYSQL)                   |
|                                                   |
+---------------------------------------------------+

• Read/Write Through Pattern

• Write Behind Caching Pattern

See Also

Redis 开发与运维

Redis 实战

缓存更新的套路