TTL indexes

With a TTL index, documents delete themselves once their lifetime passes.

Make documents delete themselves once their lifetime passes, with a TTL index on a date field.

Requirements

A user with dbAdmin or readWrite on the database.
A date field in the documents.

Create the index

JavaScript

db.sessions.createIndex({ lastSeen: 1 }, { expireAfterSeconds: 3600 });

Change the lifetime

JavaScript

db.runCommand({ collMod: "sessions", index: { keyPattern: { lastSeen: 1 }, expireAfterSeconds: 7200 } });

Check

A session whose lastSeen is more than an hour old stops showing up in queries soon after.

Common problems

A document without a date in that field, or with another type, never expires.

See also

PreviousUnique, partial and sparse indexes NextGeospatial indexes