Use Lineage for Impact Analysis

Knowing where your data comes from is key to trusting the data, and knowing who else uses it means you can analyze the impact of changes to data in your environment. The lineage feature in Tableau Catalog helps you do both these things.

Lineage requires Data Management. Starting in 2019.3, Tableau Catalog is available as part of the Data Management offering for Tableau Server and Tableau Cloud. When Tableau Catalog is enabled in your environment, you have access to lineage information for your content. For more information about Tableau Catalog, see "About Tableau Catalog" in the Tableau Server(Link opens in a new window) or Tableau Cloud(Link opens in a new window) Help.

Navigate lineage

How you navigate to the Lineage pane depends on what kind of asset you're working with.

To see the lineage for Tableau content such as workbooks, data sources, virtual connections, lenses, or flows, from Explore, navigate to and open the content asset, and then select the Lineage tab.

Note: Lineage data for flows won't show if the flow includes parameter values. For more information about using parameters in flows see Create and Use Parameters in Flows(Link opens in a new window) in the Tableau Prep help.

To see lineage for external assets, such as databases or tables, locate the asset using External Assets. Starting in Tableau Cloud October 2022 / Server 2022.3, you can also locate the asset using Explore if the asset is in a project. Click the asset, and a page opens with details about the external asset, including the name, the description, any tags, and tables or columns in it. To the right of the asset information is the Lineage pane, which shows the lineage for that external asset.

Lineage shows dependencies in relationship to the lineage anchor, which is the asset selected. A lineage anchor can be a database, table, workbook, published data source, virtual connection, virtual connection table, lens, metric, or flow. (In the first example, the anchor is the Batters data source and in the second example, it's the Batters table). All the assets below the anchor depend, either directly or indirectly, on the anchor and are called outputs or downstream assets. The assets above the anchor are the assets the anchor is either directly or indirectly dependent on and are called inputs or upstream assets.

When you select a field in a data source or a column in a table, the lineage is filtered to show only downstream assets that depend on the field (or column) or upstream inputs to the field (or column) as in this 'Superstore' workbook example that shows the lineage filtered for the Commission (Variable) field:

You can select an upstream or downstream asset in the Lineage pane to see its details. For example, when you select Metrics, the list of metrics depending on this workbook appears to the left of the Lineage pane.

From the Lineage pane, you can navigate to any asset related to your initial choice, in this case the workbook, by following the links that interest you.

Embedded asset appears in External Assets

Tableau Catalog treats an external asset as ‘embedded’ if the Include external files check box is selected when a data source or workbook is published. When an external asset (database, table, or file) is embedded in published Tableau content (workbooks, data sources, and flows), the external asset is used by the content, but is not shareable with other users. That embedded external asset appears in the lineage upstream from its Tableau content and is listed in External Assets.

To see if an external asset is embedded, go to the external asset’s detail page and see if “Embedded Asset” is listed under Category.

For information about embedded data, see Publishing data separately or embedded in workbooks(Link opens in a new window) in Tableau Desktop and Web Authoring Help.

Lineage and custom SQL connections

When you view the lineage of a connection that uses custom SQL, keep in mind the following:

• Lineage might not be complete.
• Catalog doesn't support showing column information for tables that it only knows about through custom SQL.
• Field details cards might not contain links to connected columns, or might not show any connected columns at all.
• Column details cards might not contain links to fields that use the column, or might not show any fields at all.

For more information, see Tableau Catalog support for custom SQL(Link opens in a new window) in the Tableau Desktop and Web Authoring Help.

Catalog doesn't support cubes

Cube data sources (also known as multidimensional or OLAP data sources) are not supported by Tableau Catalog. Tableau content (such as a data source, view, or workbook) that relies on cube data does not display any cube metadata or cube lineage in Catalog.

Mismatch between lineage count and tab count

You might notice a mismatch in the count of assets between the Tableau Catalog Lineage tool and the tabs in Tableau Server or Tableau Cloud.

The count mismatch is explained by the fact that each—lineage count vs. tab count—counts assets a different way. For example, at any given point in time, Catalog can count only assets that are indexed, whereas Tableau Server or Tableau Cloud counts any assets that are published. Other reasons for count differences include whether:

• You have "View" permissions for the asset.
• An asset is hidden.
• Any fields are used in a workbook.
• An asset is directly or indirectly connected to.
• An asset is in a Personal Space.

Workbook count mismatch example

As an example, here's how the tab count vs. the lineage count is determined for workbooks.

Connected Workbooks tab counts workbooks that meet both these criteria:

• Connects to the data source (whether or not any fields are actually used in the workbook).
• The user has permissions to view (whether it's a worksheet, dashboard, or story).

Tableau Catalog Lineage counts workbooks that meet all these criteria:

• Has been indexed by Tableau Catalog.
• Connects to the data source and uses at least one field in the data source.
• Contains worksheets, including dashboards or stories that contain a worksheet, that use at least one field in the data source.

When metadata is blocked because of limited permissions, or the asset is in a Personal Space, Catalog still counts the workbook. But instead of seeing some of the sensitive metadata, you see Permissions required. For more information, see Access lineage information.

Use email to contact owners

At the end of the lineage is Owners. The list of owners includes anyone assigned as the owner or contact for any content downstream from the lineage anchor.

You can email owners to let them know about changes to the data. (To email owners, you must have the 'Overwrite' (Save) capability on the lineage anchor content.)

1. Select Owners to see the list of people who are impacted by the data in this lineage.
2. Select the owners you want to send a message to.
3. Click Send Email to open the email message box.
4. Enter the Subject and your message in the text box, and click Send.