REDIS SERVER

An Introduction to REDIS SERVER, an advanced key value
database

Transcript

1. 1 REDIS SERVER An Introduction to REDIS SERVER, an advanced key value database By: Ali MasudianPour <masud.amp@gmail.com>
2. 2 What REDIS is • Redis is an open source, BSD licensed, advanced key-value store. It is often referred to as a data structure server since keys can contain strings, hashes, lists, sets and sorted sets. • REDIS – It stands for REmote DIctionary Server
3. 3 Features • not a plain key-value store, a data structures server • supporting different kind of values • Free and open source • Easy to user • Easy to learn
4. 4 Supported Data Types • Binary-safe strings. • Lists of binary-safe strings. • Sets of binary-safe strings, that are collection of unique unsorted elements. • Sorted sets, similar to Sets but where every element is associated to a floating number score. The elements are taken sorted by score.
5. 5 KEYS - VALUES • In REDIS, Keys are binary safe – This means that you can use any binary sequence as key • From String like 'foo' to the content of a JPEG file – REDIS keys accept empty • In REDIS, Values – Can not be bigger than 512MB –
6. 6 SET • To set a value to a key we use SET statement – SET key value • Example: – SET foo bar – In above example we told redis to set bar value to foo key • To set string value we use double quotations – SET keyname “The string content of value”
7. 7 GET • To get a value from redis we use GET statement – GET keyname • Example – GET foo // it will return bar – In above example we told redis to get foo key value.
8. 8 INCR, INCRBY • Automatic increment by REDIS – To use automatic increment of redis we use INCR • Example: – Set counter 1 incr counter // Output wil be 2 • We can also use INCRBY – Set counter 1 – Incr counter – // Output wil be 2 – Incrby counter 10 – //outpur will be 12
9. 9 DECR, DECRBY • In opposite of INCR and INCRBY redis contains DESC and DESCBY – Just like DECR and DECRBY – Set counter 10 decr counter // Output wil be 9 decrby counter 5 //output will be 4
10. 10 EXPIRE and TTL • In REDIS we can set keys to expire in a given and specific amount of time. – To do that we use EXPIRE command – Example • Set foo bar • Expire foo 50 – To find out how many time a key have we use TTL command • For instance after 10 second of declaring foo key if we use TTL command the output will be something like below: – Ttl foo //40
11. 11 LISTS • To create a list use LPUSH or RPUSH. If a list already exists, LPUSH will add the given value to the beginning of the list and RPUSH will add it to the end. • Redis lists contain the following commands – SORT – RPUSH – LPUSH – LLEN – LTRIM – LRANGE – LPOP – RPOP – BLPOP – BRPOP – And ...
12. 12 LISTS redis 127.0.0.1:6379> lpush ages 10 (integer) 1 redis 127.0.0.1:6379> lpush ages 13 (integer) 2 redis 127.0.0.1:6379> lpush ages 12 (integer) 3 redis 127.0.0.1:6379> lpush ages 6 (integer) 4 redis 127.0.0.1:6379> LRANGE ages 0 3 1) "6" 2) "12" 3) "13" 4) "10" redis 127.0.0.1:6379> sort ages 1) "6" 2) "10" 3) "12" 4) "13" ----------------------------- redis 127.0.0.1:6379> lpop ages "6" redis 127.0.0.1:6379> rpop ages "10" redis 127.0.0.1:6379> LRANGE ages 0 10 1) "12" 2) "13" redis 127.0.0.1:6379>
13. 13 SETS • Sets are similar to lists but does not support duplication • Example: – Add to sets • redis 127.0.0.1:6379> SADD names "Michael" (integer) 1 redis 127.0.0.1:6379> SADD names "JOHN" (integer) 1 redis 127.0.0.1:6379> SMEMBERS names 1) "JOHN" 2) "Michael" redis 127.0.0.1:6379> • SADD adds to set and SMEMMEBRS show the member of set
14. 14 Lists • Now, if you try to add another set member with JOHN value it will do nothing, because sets do not support duplication. • Other useful commands for set – SADD, SREM, SPOP, SMOVE, SCARD, SISMEMBER, SINTER, SINTERSTORE, SUNION, SUNIONSTORE, SDIFF, SDIFFSTORE, SMEMBERS, SRANDMEMBER.
15. 15 HASHES • Using a hash, you can assign values to fields in each key. • Common Commands in hashes are: – HSET, HGET, HSETNX, HMSET, HMGET, HINCRBY, HEXISTS, HDEL, HLEN, HKEYS, HVALS, HGETALL
16. 16 Example of HASHES redis 127.0.0.1:6379> hset student name "Ali" (integer) 1 redis 127.0.0.1:6379> hset student lastName "MasudianPour" (integer) 1 redis 127.0.0.1:6379> hset student number 101222 (integer) 1 redis 127.0.0.1:6379> hget student name "Ali" redis 127.0.0.1:6379> hget student lastName "MasudianPour" redis 127.0.0.1:6379> HGETALL student 1) "name" 2) "Ali" 3) "lastName" 4) "MasudianPour" 5) "number" 6) "101222"
17. 17 End • This document is provided to be a little familiar with REDIS. I hope it help you to start working with REDIS.