Databases & Data Storage
In-Memory Database
Definition
An in-memory database (IMDB) is a database management system that primarily relies on main memory (RAM) for data storage, in contrast to databases that store data on disk or SSDs.
Why It Matters
In-memory databases are exceptionally fast because reading from and writing to RAM is orders of magnitude faster than accessing a disk. They are used for applications that require microsecond response times.
Contextual Example
A real-time bidding platform for online advertising might use an in-memory database to store user profiles and ad data. This allows it to make decisions and serve an ad in the few milliseconds it takes for a webpage to load.
Common Misunderstandings
- Redis and Memcached are popular examples of in-memory data stores.
- To prevent data loss in case of a power failure, most in-memory databases have mechanisms to persist data to disk periodically.