MongoDB TTL Index. doesn't delete old documents.

Working with Data
5

Check the mongod log for anything relating to TTL.

A couple of other things to check:

  • TTL Monitor has been disabled. Check the mongod.conf(or command line parameters) for setParameter and TTLMonitorEnabled: false or db.adminCommand({getParameter:1,ttlMonitorEnabled:1})
  • If this host was previously part of a replicaSet and is subsequently running in standalone then the TTLMonitor will be disabled, this is a logged condition. If this is the case and the host will remain a standalone the drop the local database and restart mongodb db.getSiblingDB('local').dropDatabase()

ref:
https://www.mongodb.com/docs/manual/reference/parameters/#mongodb-parameter-param.ttlMonitorEnabled
https://www.mongodb.com/docs/manual/core/index-ttl/#mongod-in-standalone-mode