Page History

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Currently history configuration for MQTT Engine tags is not persistent and it may be required to delete MQTT Engine tags in certain cases. One example is UDTs which are being propagated from the Edge and the UDT definition on the Edge has been updated. This requires a user to delete all instances of the UDT under MQTT Engine and delete the corresponding UDT definition so that it can be recreated/updated at MQTT Engine for the Edge side changes to take affectReference Understanding how tag changes at the Edge affect MQTT Engine for more details.

The recommended way of configuring history for MQTT Engine tags is to use reference tags to indirectly reference MQTT Engine tags. This allows the history configuration to be persisted on the reference tag when the underlying MQTT Engine tags are deleted. 

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All historic data will be written to the tag using the timestamp associated with the historical data.

Edge Client 

If you are not using reference tags, the Edge side client must publish historic data in-order (synchronously) before live data resumes. This is because Ignition will ignore writes to the tag if the timestamp on the tag change is older that the current value.

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• Suitable only for writing historical events directly to the database
• Real-time data is written to the storage provider on the Sample Rate whilst the tag quality is Good
• Historical data is written to the storage provider using the timestamp associated with the historical data
  • Max Time Between Samples inserts will not be inserted into the middle of historical data

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backfill backfill

Ignition Allow Back-fill Data

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