Preface
As a typical key-value database with high performance, high reliability and high scalability, Redis is not only powerful but also stable, and it has naturally become the first choice of large Internet companies.
When many large companies recruit, they will not only require the interviewee to simply use Redis, but also have a deep understanding of the underlying implementation principles and the ability to solve common problems. It can be said that mastering Redis has become an essential skill for technical people.
However, in the process of learning and using Redis, it is inevitable to encounter some difficult problems, such as:
- How should Redis key and data structure be designed? What are the best practices?
- How does Redis cluster balance data? How to scale horizontally?
- How to ensure data consistency? How to solve the problem of hot data?
- The data snapshot generated by RDB persistence, is each update a full update or an incremental update?
- How to solve problems such as cache avalanche, cache penetration, cache warm-up, cache update, and cache degradation?
- How to read Redis source code efficiently?
Based on my years of working experience, I sorted out a set of systematic Redis learning methods. The complex Redis knowledge and problems are summarized in the framework of "two dimensions and three main lines" to help readers establish a system view and a global view, so as to thoroughly understand the underlying implementation principles. Let's take a look at the general content:
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Introduction to Redis
- The difference between Redis and Memcached
- Redis advantages
- Redis disadvantages
Redis data type
- String
- Hash
- List
- Set
- Sorted set
Redis transaction
- MULTI&EXEC (atomic execution, not mutually exclusive)
- WATCH&UNWATCH (atomic execution + optimistic locking)
Redis distributed lock
- Exclusive lock SETNX
- Lock with timeout feature
Redis persistence mechanism
- RDB (Redis Database, full mode)
- AOF (Append Only File, incremental mode)
- Trigger method
- Compare with each other
- RDB best strategy
- AOF best strategy
- Redis message queue
Redis advanced data structure
- BitMap (some other commands of String)
- Expiration strategy
- Memory elimination strategy
- Master-slave replication (data is synchronized, similar to MySQL Replication)
- Sentinel (data is synchronized)
- Cluster (data is sharded, sharing)
- Hash mapping (not a consistent hash, but a hash slot)
- Data fragmentation
- Communication protocol between nodes-Gossip
- Master-slave election-Raft
- Functional limitations
- Data migration/online expansion
- Codes
- twemproxy
Configuration file + application scenario + Lua script + consistent with DB
Redis source code
- Thread model-single thread
- RedisObject
This document starts with the construction of the key architecture of a key-value database. It not only takes you to establish an overall view, but also helps you quickly grasp the core main line. In addition, it will explain the data structure, thread model, network framework, persistence, master-slave synchronization and slice cluster in detail to help you understand the underlying principles. I believe this is a perfect tutorial for all levels of Redis users.
At last
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