NoSQL series: Redis (1)

NoSQL series: Redis (1)

Redis environment preparation rredis function library rredis basic Use Cases

Each chapter is divided into "text description" and "code section" to ensure consistency between the text description and the code.

Chapter 1 prepare the Redis Environment

Text description:

First, prepare the environment. Here I chose the 64-bit server version of Linux Ubuntu operating system 12.04. You can choose a proper Linux version based on your usage habits.

Redis installation is skipped. Sudo apt-get install redis-server

View the Redis server environment

Run the/etc/init. d/redis-server command to start redis-server. The default port is port = 6379.

On the server side, use telnet to connect to redis-server

Use telnet to insert data and read data

In the R language environment 2.15.0, WinXP remotely connects to the Redis server.

Code Section:

View Operating System

 
 

  
  
~ uname -a      Linux AY121111030241cda8003 3.2.0-29-generic #46-Ubuntu SMP Fri Jul 27 17:03:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux  ~ cat /etc/issue      Ubuntu 12.04.1 LTS \n \l  
 
 

Start redis

 
 

  
  
~ /etc/init.d/redis-server start      Starting redis-server: redis-server.  
 
 

View System Processes

 
 

  
  
~ ps -aux|grep redis      redis    20128  0.0  0.0  10676  1428 ?        Ss   16:39   0:00 /usr/bin/redis-server /etc/redis/redis.conf  
 
 

View startup logs

 
 

  
  
~ cat  /var/log/redis/redis-server.log       
  
  
[20128] 14 Apr 16:39:43 * Server started, Redis version 2.2.12     
  
  
[20128] 14 Apr 16:39:43 # 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.    
  
  
[20128] 14 Apr 16:39:43 * The server is now ready to accept connections on port 6379  
 
 

Telnet to redis-server

 
 

  
  
~ telnet localhost 6379      Trying 127.0.0.1...     Connected to localhost.     Escape character is '^]'.  
 
 

Insert data

 
 

  
  
rpush data 1     :1      rpush data 2     :2  
 
 

Query data

 
 

  
  
lrange data 0 -1     *2     $1     1     $1     2  
 
 

R Language Development Environment 2.15.0, WinXP

~ R R version 2.15.0 (2012-03-30) Copyright (C) 2012 The R Foundation for Statistical Computing ISBN 3-900051-07-0 Platform: i386-pc-mingw32/i386 (32-bit) 

Chapter 2 rredis function library

Rredis provides the 100 function to operate on redis applications. Although there are many functions, the usage is relatively simple, the R language is flexible enough, and the code is concise.

The following lists all the rredis function libraries. I only select some common introduction.

Text description:

Establish a connection and close the connection

 
 

  
  
redisConnect() , redisClose()  
 
 

Clear current/All Database Data

 
 

  
  
redisFlushDB() , redisFlushAll()  
 
 

List all KEY values and number of keys

 
 

  
  
redisKeys(), redisDBSize()  
 
 

Select to switch Database: 0 is the default database

 
 

  
  
redisSelect(0)      
 
 

Insert string objects in batches

 
 

  
  
redisSet('x',runif(5)), redisMSet(list(x=pi,y=runif(5),z=sqrt(2)))  
 
 

Reads string objects in batches

 
 

  
  
redisGet('x'), redisMGet(c('x','y','z'))  
 
 

Delete object

 
 

  
  
redisDelete('x')  
 
 

Insert array object on the left and array object on the right

 
 

  
  
redisLPush('a',1), redisRPush('a','A')  
 
 

An array object is displayed on the left, and an array object is displayed on the right,

 
 

  
  
redisLPop('a'), redisRPop('a')  
 
 

List of array objects on the left

 
 

  
  
redisLRange('a',0,-1)  
 
 

Insert a set object

 
 

  
  
redisSAdd('A',runif(2))  
 
 

Displays the set object with several elements. The List displays the set object elements.

 
 

  
  
redisSCard('A'), redisSMembers('A')  
 
 

Display the difference set, intersection, and union of two set objects

 
 

  
  
redisSDiff(c('A','B')),redisSInter(c('A','B')),redisSUnion(c('A','B'))  
 
 

Code Section:

A total of 100 functions

redisAuth redisBgRewriteAOF redisBgSave redisBLPop redisBRPop redisBRPopLPush redisClose redisCmd redisConnect redisDBSize redisDecr redisDecrBy redisDelete redisDiscard redisEval redisExec redisExists redisExpire redisExpireAt redisFlushAll redisFlushDB redisGet redisGetContext redisGetResponse redisGetSet redisHDel redisHExists redisHFields redisHGet redisHGetAll redisHIncrBy redisHKeys redisHLen redisHMGet redisHMSet redisHSet redisHVals redisIncr redisIncrBy redisInfo redisKeys redisLIndex redisLLen redisLPop redisLPush redisLRange redisLRem redisLSet redisLTrim redisMGet redisMonitorChannels redisMove redisMSet redisMulti redisPublish redisRandomKey redisRename redisRPop redisRPopLPush redisRPush redisSAdd redisSave redisSCard redisSDiff redisSDiffStore redisSelect redisSet redisSetBlocking redisSetContext redisShutdown redisSInter redisSInterStore redisSIsMember redisSlaveOf redisSMembers redisSMove redisSort redisSPop redisSRandMember redisSRem redisSubscribe redisSUnion redisSUnionStore redisTTL redisType redisUnsubscribe redisUnwatch redisWatch redisZAdd redisZCard redisZIncrBy redisZInterStore redisZRange redisZRangeByScore redisZRank redisZRem redisZRemRangeByRank redisZRemRangeByScore redisZScore redisZUnionStore 

Chapter 3 basic operations of rredis

Text description:

First, install the rredis class library and load the class library.

RedisConnect (host = "192.168.1.101", port = 6379)

Then, use the redisConnect () function to establish a connection with the Redis Server. If the local connection redisConnect () is not a parameter, the following example uses remote connection and adds the host parameter to configure the IP address. RedisConnect (host = "192.168.1.101", port = 6379)

Basic operations of redis: it is recommended to link to switch the database. The List displays all KEY values, clears the current database data, clears all database data, and closes the link,

String-type operations: insert, read, delete, insert and set expiration time, batch operations

List Operation: insert, read, and pop-up

Set Operations: insert, read, intersection, difference set, and Union

Interaction between rredis and redis-cli

Code Section:

Basic operations of redis:

 
 

  
  
# Installing rredis
  
  
Install. packages (rredis)
  
  
 
  
  
# Loading the rredis class library
  
  
Library (rredis)
  
  
 
  
  
# Remote connection to redis server
  
  
RedisConnect (host = "192.168.1.101", port = 6379)
  
  
 
  
  
# Listing all keys
  
  
RedisKeys ()
  
  
[1] "x" "data"
  
  
 
  
  
# How many keys are displayed
  
  
RedisDBSize ()
  
  
[1] 2
  
  
 
  
  
# Switching database 1
  
  
RedisSelect (1)
  
  
[1] "OK"
  
  
RedisKeys ()
  
  
NULL
  
  
 
  
  
# Switching database 0
  
  
RedisSelect (0)
  
  
[1] "OK"
  
  
RedisKeys ()
  
  
[1] "x" "data"
  
  
 
  
  
# Clearing data in the current database
  
  
RedisFlushDB ()
  
  
[1] "OK"
  
  
 
  
  
# Clear all database data
  
  
RedisFlushAll ()
  
  
[1] "OK"
  
  
 
  
  
# Close the link
  
  
RedisClose ()
 
 

String type operation:

 
 

  
  
# Insert object
  
  
RedisSet ('x', runif (5 ))
  
  
1] "OK"
  
  
 
  
  
# Reading objects
  
  
RedisGet ('x ')
  
  
[1] 0.67616159 0.06358643 0.07478021 0.32129140 0.16264615
  
  
 
  
  
# Set the data expiration time
  
  
RedisExpire ('x', 1)
  
  
Sys. sleep (1)
  
  
RedisGet ('x ')
  
  
NULL
  
  
 
  
  
# Batch insert
  
  
RedisMSet (list (x = pi, y = runif (5), z = sqrt (2 )))
  
  
[1] TRUE
  
  
 
  
  
# Batch read
  
  
RedisMGet (c ('x', 'y', 'z '))
  
  
$ X
  
  
[1] 3.141593
  
  
$ Y
  
  
[1] 0.9249501 0.3444994 0.6477250 0.1681421 0.2646853
  
  
$ Z
  
  
[1] 1.414214
  
  
 
  
  
# Deleting data
  
  
RedisDelete ('x ')
  
  
[1] 1
  
  
RedisGet ('x ')
  
  
NULL