Hi,
I'm curious about the speed difference between Tag Historian and SQL Bridge.
If the period is 2s for both, is there any speed difference in saving data to DB?
Or is there a difference in load on data delivery?
The SQL Bridge module places many values into each inserted row. The Tag Historian places every value in its own row. The DB has to index the rows inserted, and has much more work to do with the tag historian if many or most of the values are changing every two seconds. The tag historian will also store a lot more ancillary data in the DB to keep track of those values.
The tag historian's big advantage in many applications is not recording when values aren't changing.
If you must record multiple tags every two seconds, whether changed or not, use the SQL Bridge module, or script the equivalent with a gateway event. You will save a lot of storage and the DB will have less work and the DB will be able to query the data easier.
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