Page History

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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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History Configuration Examples

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example1 example1

Sample Mode = On Change, Min Time Between Samples = 0, Max Time Between Samples = 0

• Suitable for writing historical events directly to the database or writing historical events directly to the tag
• Real-time data is written to the storage provider on each tag change event whilst the tag quality is Good
• Historical data is written to the storage provider or tag using the timestamp associated with the historical data 
  • Handles historical metrics flushed from the Edge that have very high resolution; e.g., the historical metrics have timestamps 1 ms apart for a single tag

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example2 example2

Sample Mode = On Change, Min Time Between Samples = 0, Max Time Between Samples = 5

• Suitable for writing historical events directly to the database or writing historical events directly to the tag
• Real-time data is written to the storage provider on each tag change event whilst the tag quality is Good
• Real-time data is written to the storage provider on the Max Time Between Samples interval if no tag change events whilst the tag quality is Good
• Historical data is written to the storage provider or tag using the timestamp associated with the historical data 
  • When the Max Time Between Samples > 0, there will be no inserts during a history flush as the tag updates occur too quickly
  • Handles historical metrics flushed from the Edge that have very high resolution; e.g., the historical metrics have timestamps 1 ms apart for a single tag

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example3 example3

Sample Mode = Periodic, Max Time Between Samples = 0, Sample Rate = 5

• 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
  • When the Max Time Between Samples > 0, there will be no inserts during a history flush as the tag updates occur too quickly

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