Whether the live mqtt messages will be stored in MongoDB within Ditto solution? How can I check if these messages stored?

Question

From Ditto architecture, MongoDB should store all MQTT messages. Not sure the live messages? When I go into MongoDB, query collection, can't find anything although I find "things" db has certain size. Is there anyway to check if mqtt messages have been stored in MongoDB?

Answer 1

Live messages are not stored in MongoDB as described in the documentation. Only twin commands affect the persisted state of a digital twin / thing in the database.

If you however mean that the payload of your MQTT message is a twin command, that one should change the persisted state of a twin.

If you need to check in the database, check the things_journal prefixed MongoDB collections if the event which resulted from a twin command was persisted (see also the architectural style docs).