Redis
Wenzhi Xu
Redis is an in-memory data storage software.
FAST
OPEN-SOURCE
SIMPLE
NOSQL
POPULAR
CROSS-PLATFORM
Where to use it?
1. Caching - Speed up your application
2. Leaderboard - Sort by weight
3. Database - Store anything you want
4. Message Queue - asynchronous program
5. Session Store - Centralized storage of SESSION data
...
1. Basic Usage
2. Redis Data Structure
3. Redis Network Model
...
Install
wget http://download.redis.io/redis-stable.tar.gz
tar xvzf redis-stable.tar.gz
cd redis-stable
makeBy source code
yum install redis
# or
apt-get install redisBy package installer
After installation we'll get
1. redis-server : Start redis server
2. redis-cli : To connect redis server
3. redis-benchmark : To test redis performance
4. redis-check-aof and redis-check-rdb : To check data persistence on disk
5. redis-sentinel : monitor
Start Redis
Connect to Redis
Store new value
Data Types in Redis
1. String - set, get, del, expire
2. List - lpush, lpop, rpush,rpop, lrange, lindex
3. Hash - hset, hget, hgetall, hdel, hexists
4. Set - sadd, smembers, srem
5. Sorted Set - zadd, zrem, zrange
Don't confuse about data types and data structure. Data types can be implemented by one or more data structures.
String Usage
redis> get school
City University of Seattle.
redis> set school "CityU Seattle"
OK
redis> get school
CityU Seattle
redis> set F324FSF@$FSFF@#$#@$#@FFS4324424324 '{userId:
1, first:"Wenzhi", last:"Xu"}'
OK
redis> get F324FSF@$FSFF@#$#@$#@FFS4324424324
{userId:1, first:"Wenzhi", last:"Xu"}
redis> expire school 10
1
redis> get school
CityU Seattle
# after 10 seconds
redis> get school
nullList Usage
redis> lpush task "CT"
1
redis> rpush task "DB"
2
redis> rpush task "KC"
3
redis> rpush task "PE"
4
redis> lrange 0 10
ERR wrong number of arguments for 'lrange' command
redis> lrange task 0 10
0 CT
1 DB
2 KC
3 PE
redis> lpush task "MP"
5
redis> lrange task 0 10
0 MP
1 CT
2 DB
3 KC
4 PEHash Usage
redis> hset state WA Washington
1
redis> hset state CA California
1
redis> hset state NY New York
ERR wrong number of arguments for 'hset' command
redis> hset state NY 'New York'
1
redis> hget state NY
New York
redis> hset session F324FSF@$FSFF@#$#@$#@FFS4324424324
'{userId:1, first:"Wenzhi", last:"Xu"}'
1
redis> hget session F324FSF@$FSFF@#$#@$#@FFS4324424324
{userId:1, first:"Wenzhi", last:"Xu"}As you can see, we can use Hash to store SESSION as well.
Which one should we use?
Sorted Set Usage
redis> zadd billboard 0 "Drivers License"
1
redis> zadd billboard 1 "Mood"
1
redis> zadd billboard 3 "Blinding Lights"
1
redis> zadd billboard 2 "Positions"
1
redis> zadd billboard 6 "Holy"
1
redis> zadd billboard 5 "Levitating"
1
redis> zadd billboard 4 "Go Crazy"
1
redis> zrange billboard 0 10
0 Drivers License
1 Mood
2 Positions
3 Blinding Lights
4 Go Crazy
5 Levitating
6 Holy
# get top 3
redis> zrange billboard 0 2
0 Drivers License
1 Mood
2 PositionsCaching?
Assume Blackboard cache our profile data for speed up.
get_user_profile(user_id)
cached_user_profile = redis.get(user_id)
if cached_user_profile != nil:
return cached_user_profile
user_profile = db.get_user()
return user_profileLanguage Supporting
https://redis.io/clients
For Python
In [1]: import redis
In [2]: r = redis.Redis(host='localhost', port=6379, db=0, password="foobared")
In [3]: r.get('school')
Out[3]: 'CityU Seatlle'QA
Reference
https://redis.io/commands https://redis.io/commands/expire https://aws.amazon.com/elasticache/redis/
Thanks!
Redis
By xuwenzhi
