TDengine TSDB

Global – October 27, 2026 -- QoS 1 is the practical starting point for most industrial telemetry over MQTT, but none of the three QoS levels guarantees a complete historian, according to engineering guidance tied to the OASIS MQTT 5.0 standard.

QoS 1 reduces the risk of losing a message on an MQTT delivery hop. The receiving system must tolerate duplicates. QoS 0 fits replaceable readings where low overhead matters more than complete delivery. QoS 2 is reserved for flows where duplicate delivery on that hop is unacceptable and the extra protocol exchange is justified.

MQTT QoS covers one sender-receiver hop, not the whole pipeline

The OASIS MQTT 5.0 standard defines QoS for a single delivery flow. A device publishing to a broker is one flow. The broker sending to a subscribing collector is another, and it can use a different QoS depending on the original publication and the subscriber's granted maximum.

Global – October 27, 2026 -- Industrial teams can locate missing historian records by tracing one test message across five boundaries: broker receipt, subscriber receipt, parsing, database write and query. The approach comes from troubleshooting guidance on TDengine's MQTT ingestion, which warns that a live broker feed or a connected publisher proves only part of the chain.

One tagged test message anchors the diagnosis

Engineers should publish a single message for one equipment tag through the approved production path, such as plant/line2/pump07/pressure. They should log the exact topic, payload bytes, broker timestamp, publisher identity, destination table and intended source timestamp. Each test needs a fresh timestamp, because identical timestamps can make a successful write indistinguishable from an earlier one.