First acquaintance and basic operation of Reids

- Preface

Preface

REmote DIctionary Server (Redis) is a key-value storage system written by Salvatore Sanfilippo.

Redis is an open source log-type, Key-Value database that is written in ANSI C language, complies with the BSD protocol, supports the network, can be memory-based or persistent, and provides APIs in multiple languages. It is usually called a data structure server because the value can be of string (String), hash (Hash), list, set, and sorted sets.

Three major roles

database
Cache
Message middleware MQ

Extension:
Redis bottleneck:
Redis is single-threaded, based on memory operations, CPU is not a performance bottleneck, the bottleneck is memory and network bandwidth

Why is redis fast?
Redis puts all the data in the memory, so single thread is the highest, because multi-threaded cpu takes more time to switch between the door and the door. For the memory system, if there is no context switch, single thread is The best. The cpu switch is between 1000-1500 nanoseconds.

Five types

Strings

Hashes (hash)

Lists

Sets

Sorted Sets (Ordered Sets)
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Three special data types

Bitmap
Geo
GEOADD

Basic Redis operation

Redis has 16a database by default

vim  /redis.conf   # 查看配置文件

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The number of the library is 0-15. The
default entry is library 0

select 2 Switch to the second database

set name jack Create a key with name value jack

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type name View the value type of the name key
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MSET age1 10 age2 20 Create multiple values at the same time
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DBSIZEView the capacity of the database

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keys * View all keys of the current database*

get name View the value of the name key
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flushdb Clear the current library

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flushallClear all libraries (open RDB persistence, the data is saved on the disk) to
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exists namedetermine whether the name key exists. If it returns 1, it exists, 0 does not exist.

move name 2Move the name key to the second library.

del nameDelete the name key

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EXPIRE name 30 Set the value of the name key to be valid for 30 seconds, and clear the value after expiration (1. For example, store a cookie and expire after half a month 2. Single sign-on, set the expiration time 3. Verification code)
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TTL name View remaining time
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Value is empty after expiration
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