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簡介

redis install

  • Introduction to Redis data types. http://redis.io/topics/data-types-intro
  • Try Redis directly inside your browser. http://try.redis.io
  • The full list of Redis commands. http://redis.io/commands
  • There is much more inside the Redis official documentation. http://redis.io/documentation

內容

準備

  • gcc -v
  • yum install gcc-c++

下載，安裝

$ wget http://download.redis.io/releases/redis-5.0.0.tar.gz
$ tar zxvf redis-5.0.0.tar.gz
$ ln -s redis-5.0.0 redis
$ cd redis
$ make

Running Redis

To run Redis with the default configuration just type:

% cd src
% ./redis-server

檢查是否啟動

  • ps -ef | grep redis | grep -v grep
  • netstat -tlanp 6379
  • lsof -i:6379

net.core.somaxconn

WARNING: The TCP backlog setting of 511 cannot be enforced because /proc/sys/net/core/somaxconn is set to the lower value of 128 net.core.somaxconn是Linux中的一个kernel参数，表示socket监听（listen）的backlog上限。什么是backlog呢？backlog就是socket的监听队列，当一个请求（request）尚未被处理或建立时，他会进入backlog。而socket server可以一次性处理backlog中的所有请求，处理后的请求不再位于监听队列中。当server处理请求较慢，以至于监听队列被填满后，新来的请求会被拒绝。

如何修改net.core.somaxconn

sysctl -a //会显示所有的kernel参数及值。 
vim /etc/sysctl.conf //編輯
net.core.somaxconn=32768 

sysctl -p //然后执行命令

WARNING overcommit_memory

WARNING overcommit_memory is set to 0! Background save may fail under low memory condition. To fix this issue add vm.overcommit_memory = 1 to /etc/sysctl.conf and then reboot or run the command 'sysctl vm.overcommit_memory=1' for this to take effect.

WARNING you have Transparent Huge Pages (THP)

WARNING you have Transparent Huge Pages (THP) support enabled in your kernel. This will create latency and memory usage issues with Redis. To fix this issue run the command echo never > /sys/kernel/mm/transparent_hugepage/enabled as root, and add it to your /etc/rc.local in order to retain the setting after a reboot. Redis must be restarted after THP is disabled.

Playing with Redis

You can use redis-cli to play with Redis. Start a redis-server instance, then in another terminal try the following:

% cd src
% ./redis-cli
redis> ping
PONG
redis> set foo bar
OK
redis> get foo
"bar"
redis> incr mycounter
(integer) 1
redis> incr mycounter
(integer) 2
redis>

make install

You can use make PREFIX=/some/other/directory install if you wish to use a different destination.

RDB

AOF

命令

  • SELECT index（切換數據庫）
  • Dbsize(查看數據庫的key數量)
  • FlushDb(清空當前數據庫)
  • Flushall（數據庫通殺）

參考資料