Key-value store is a special type of database storage system where data is stored in form of key and value pairs.

Redis is different compared to other key-value stores because of the following:

  • Redis is a different evolution path in the key-value databases where values can contain more complex data types, with atomic operations defined on those data types.
  • Redis data types are closely related to fundamental data structures and are exposed to the programmer as such, without additional abstraction layers.
  • Redis is an in-memory but persistent on disk database, so it represents a different trade off where very high write and read speed is achieved with the limitation of data sets that can't be larger than memory.
  • Another 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.
  • At the same time the two on-disk storage formats (RDB and AOF) don't need to be suitable for random access, so they are compact and always generated in an append-only fashion.