What does the term "instance" mean for a database?

A database instance is a running copy of the DBMS server software that manages the database files and performs operations on them.

In simpler terms, it's the active process or service that keeps a database running.

#The difference from a database

A database is the data itself: files, tables, indexes, logs. An instance is the "engine" that manages those files: it accepts requests, reads and writes data, and allocates memory and resources.

Example:

• A server has a PostgreSQL instance running.
• Inside it there can be several databases (db1, db2, db3).
• When the instance stops, the databases stay on disk, but you can't work with them until the instance starts again.

So an instance is a process, and a database is data.