How to implement the underlying redis

Redis uses hash tables to store data and supports data structures such as strings, lists, hash tables, collections and ordered collections. Redis persists data through snapshots (RDB) and append write-only (AOF) mechanisms. Redis uses master-slave replication to improve data availability. Redis uses a single-threaded event loop to handle connections and commands to ensure data atomicity and consistency. Redis sets the expiration time for the key and uses the lazy delete mechanism to delete the expiration key.

Redis underlying implementation

How does Redis store data?

Redis uses a memory data structure called a hash table to store data. A hash table is a collection that maps keys to values. The value of the key is generated by a hash function and stored in the slot of the hash table.

What are the data structures of Redis?

Redis supports a variety of data structures, including:

• String: Store text or binary data
• List: A collection of ordered elements
• Hash table: Store key-value pairs
• Collection: Store unordered unique elements
• Ordered set: Store unique elements and sort by fractional values

How does Redis handle persistence?

Redis provides persistence features that allow data to be saved to disk. There are two persistence mechanisms:

• Snapshot (RDB): Save the status of the Redis database to a single file.
• Append write-only (AOF): Record the write operation to the database into the log file.

How does Redis handle replication?

Redis supports master-slave replication, where one master server replicates data to multiple slave servers. When a master server fails, one of the slave servers can be promoted to the master server.

How does Redis handle concurrent access?

Redis uses a single-threaded event loop to handle all connections and commands. The server processes one command at a time, which ensures the atomicity and consistency of the data.

How does Redis handle expired keys?

Redis sets an expiration time for each key. When the key expires, its related data will be deleted automatically. The server uses the lazy delete mechanism, which means it does not delete the expired key immediately, but marks it as delete and actually deletes it at the appropriate time.

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