Data Architecture

MQTT Brokers Cannot Replace Historians in Industrial Pipelines

Global – October 27, 2026 -- Even QoS 2's exactly-once delivery covers only one MQTT sender-receiver flow, not the subscriber's database transaction, so an MQTT broker cannot serve as an industrial historian. A broker moves messages between publishers and subscribers. A historian keeps time-indexed records that engineers can query, trend and aggregate later.

Broker retention mechanisms fall short of historical storage

A retained message is only the current message for a topic, and a new one normally replaces the prior state. A persistent session preserves subscriptions and eligible queued messages for an offline client. Session expiry, broker capacity, message expiry and administrative policy can all limit what remains.

Broker persistence protects broker state across restarts. It does not define table schemas, engineering timestamps, multi-year retention, SQL queries, aggregates or audit-ready change history.

OPC UA vs MQTT: Match the Protocol to the Plant Data Role

Global – October 27, 2026 -- Industrial data architects should choose OPC UA when a collector must discover and read a structured source, and MQTT when producers publish through a broker to one or more consumers, according to a TDengine technical comparison. The guide adds that the two names do not describe equivalent layers, so the rule is only a starting point.

OPC UA preserves equipment context that MQTT leaves to the architect

OPC UA is a family of specifications covering Client/Server services, information modeling, Alarms and Conditions, Historical Access and PubSub. A server can organize measurements under equipment objects, attach engineering units and ranges, and expose status, timestamps and methods. A client can browse that address space instead of encoding meaning in topic strings.

Not every server delivers a rich model, however. Some expose flat tag lists, incomplete metadata or vendor-specific structures.