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레디스 키

#lecture #redis #data-structure #keys

1. Key

Redis Key - Definition

  • Keys are the primary way to access data values within Redis.
  • The majority of Redis commands operate a key or keys.

Redis Key - Properties

  • Unique
  • Binary safe
    • "Foo", 42, 3.1415, 0xff
  • Key names can be up to 512MB
  • Trade-off - Length versus Readability

2. Key Spaces

  • Logical Databases
  • Flat key space
  • No automatic namespacing
  • Naming conventions

3. Logical Databases

  • identified by a zero-based index.
  • default is database 0.
  • within a logical database, the key names are unique.
  • but the same key name can appear in multiple logical databases.
  • RDB 의 Schema 와 유사한 개념인듯
  • Practical 한 관점에서 하나의 Application 이라도 CACHE 는 0번 DB에 저장하고 SESSION 은 1번 DB에 저장하는 식으로 구분하는것이 좋다.
id 가 3번인 DB에 연결하는 redis-cli 옵션
> redis-cli -n 3
127.0.0.1:6379[3] >

4. Key naming convention

  • user🆔followers
    • "user:1000:followers"
    • object name
    • unique identifier
    • composed object name

5. Keys, Scan - 모든 키를 조회하는 커맨드

  • https://redis.io/commands/keys/
  • https://redis.io/commands/scan/
KEYS SCAN
Blocks until complete Iterates using a cursor
Never use in production Returns a slot reference
Useful for debugging May return 0 or more keys per call
safe for production

5.1 Keys example

> keys customer:1*
1) "customer:1000"
2) "customer:1500"

5.2 Scan example

> scan 0 MATCH customer:1*
1) "14336"
2) "(empty list or set)"

> scan 14336 MATCH customer:1*
1) "14848"
2) "(empty list or set)"

> scan 14848 MATCH customer:1* COUNT 10000
1) "1229"
2) 1) "customer:1500"
   2) "customer:1000"

> scan 14848 MATCH customer:1* COUNT 10000
1) "0"
2) "(empty list or set)"

6. DEL, UNLINK - 키를 제거하는 명령어

https://redis.io/commands/del/ https://redis.io/commands/unlink/

DEL UNLINK
Blocking Non-blocking
Last update: May 16, 2023
Created: May 16, 2023