View Lineage and Impact Overview
Lineage and impact describes the end-to-end data flow for an asset. The data flow for an asset has two components, the lineage and the impact.
Lineage describes the flow of data from the origins to an asset. Lineage shows you where the data for an asset comes from and which assets affect the asset that you are viewing. When you view an asset in a lineage and impact diagram, the lineage includes the asset that you are viewing and all of the upstream assets in the data flow.
Impact describes the flow of data from an asset to the destinations. Impact shows you where the data is used and which assets might be affected if you change the asset that you are viewing. When you view an asset in a lineage and impact diagram, the impact includes the asset that you are viewing and all of the downstream assets in the data flow.
You view the lineage and impact information for an asset in the Lineage and Impact tab. The asset from which you open the Lineage and Impact tab is called the seed asset. The Lineage and Impact tab contains the diagram view, compact view, and asset summary view. The Lineage and Impact tab, by default, displays the diagram view for the asset. You can toggle between the diagram view and compact view in the Lineage and Impact tab. Use the Classic View option to toggle between the diagram view and compact view. The classic view refers to the diagram view.
You can choose to display the summary information for the assets in the asset summary page. The asset summary view contains the Asset Lineage Summary, Asset Impact Summary, and Asset Control Summary tabs. The Asset Lineage Summary tab lists all the assets in the data flow from the origins to the seed asset. The Asset Impact Summary tab lists all assets in the data flow from the seed asset to the destinations. The Asset Control Summary tab displays all the assets that control the seed asset in the data flow, and assets that the seed asset controls.
The Lineage and Impact tab also displays associated business terms and transformation logic for assets that contain transformations. You can also filter, export, and print the lineage and impact view.
View the lineage and impact for an asset to answer the following types of questions:
- How is a field in a report derived?
- An analyst at your organization needs to find out which fields or columns are used to calculate the Cost Ratio field in a Tableau report. She searches for "Cost Ratio" in the catalog and opens the Lineage and Impact tab for the asset. The analyst views the lineage and impact diagram and discovers that Cost Ratio is calculated directly from a table in a data warehouse. The analyst can then perform further analysis on the table.
- If I replace an asset, which other assets might be affected? Who owns the affected assets?
- A developer at your organization owns relational table "Transactions_DB" that is obsolete and needs to be replaced with a different table. He searches for "Transactions_DB" in the catalog and opens the Lineage and Impact tab for the asset. The developer discovers that the table is used in multiple Business Intelligence reports. He opens the asset summary and finds the names of the users that are associated with the report assets. The developer then notifies them that the table will be replaced.