Question

Why is _fivetran_synced different than the load time?

Environment

All connectors.

Answer

Connectors supply their own values for this column. However, when core sets it by default, it is set when the connectors call into core with the row’s data. This can be some time after the data was actually extracted though (depending on what extracted means exactly given transactions).

The default value of the _fivetran_synced time is set a step after the extraction time when the connector is processing the data prior to loading it. This puts the _fivetran_synced value between when it has been extracted from the source and when it is loaded to the warehouse.

Some connectors may override this and set the value closer or further from the actual extracted time, but it will never be less than the extracted time or greater than the load time. The _fivetran_synced time is the time the data was extracted from the source. This identifies that the warehouse data will match the data in the source to that point in time.

The load of the data occurs at a later time. First, the connector extracts all the latest updates, the time of extraction being _fivetran_synced. After the extraction process is completed, the connector loads the extracted data, resulting in a different load time to the _fivetran_synced time of the data.