By the end of this chapter, you should be able to:
From the docs
Redis is an open source, in-memory data structure store, used as a database, cache and message broker. It supports data structures such as strings, hashes, lists, sets, sorted sets with range queries, bitmaps, hyperloglogs and geospatial indexes with radius queries. Redis has built-in replication, Lua scripting, LRU eviction, transactions and different levels of on-disk persistence, and provides high availability via Redis Sentinel and automatic partitioning with Redis Cluster.
Redis typically holds the whole dataset in memory. Persistence is now achieved in two different ways: one is called snapshotting, and is a semi-persistent durability mode where the dataset is asynchronously transferred from memory to disk from time to time, written in RDB dump format.
A safer alternative is AOF, an append-only file (a journal) that is written as operations modifying the dataset in memory are processed. Redis is able to rewrite the append-only file in the background in order to avoid an indefinite growth of the journal.
By default, Redis writes data to a file system at least every 2 seconds, with more or less robust options available if needed. In the case of a complete system failure on default settings, only a few seconds of data would be lost.
An advantage of in memory databases is that the memory representation of complex data structures is much simpler to manipulate compared to the same data structure on disk, so Redis can do a lot, with little internal complexity. RAM is incredibly fast, but usually quite limited and expensive.
You can read more about it here
Although Redis is often called a
key-value store, it does not simply just store keys and values. Redis provides access to many different kinds of data structures to serve different use cases. The
values that Redis can store are far more than just "strings" and include
Depending on the use case, each of these data structures aim to solve different problems with the optimal time and space complexities.
brew install redis
brew services start redis
exitto get out)
Some of the most common use cases for Redis include:
When you're ready, move on to Authentication with Passport Local