system-design-primer/resources/noat.cards/Key-value store.md

1.2 KiB

+++ noatcards = True isdraft = False +++

Key-value store

Abstraction: hash table

A key-value store generally allows for O(1) reads and writes and is often backed by memory or SSD. Data stores can maintain keys in lexicographic order , allowing efficient retrieval of key ranges. Key-value stores can allow for storing of metadata with a value.

Key-value stores provide high performance and are often used for simple data models or for rapidly-changing data, such as an in-memory cache layer. Since they offer only a limited set of operations, complexity is shifted to the application layer if additional operations are needed.

A key-value store is the basis for more complex system systems such as a document store, and in some cases, a graph database.

Source(s) and further reading: key-value store