documentation/Database-Information-and-Maintenance.md

Invidious needs one PostgreSQL database which has the following tables.

channel_videos Stores truncated video info, used to create user feeds
channels Stores UCID and author name
nonces Keeps track of tokens issued to prevent CSRF
users Stores user info, such as preferences, username, subscriptions
session_ids Keeps track of user sessions
videos Stores video cache, used to create "top" page

The table videos grows a lot and needs the most storage. You can clean it up using following commands:

$ sudo -i -u postgres
$ psql invidious -c "DELETE FROM nonces * WHERE expire < current_timestamp"
$ psql invidious -c "TRUNCATE TABLE videos"
$ exit

For regular maintenance you should add a cronjob for these commands

@weekly psql invidious -c "DELETE FROM nonces * WHERE expire < current_timestamp" > /dev/null
@weekly psql invidious -c "TRUNCATE TABLE videos" > /dev/null