Enable Unified Source Tags Model

Alation Cloud Service Applies to Alation Cloud Service instances of Alation

Customer Managed Applies to customer-managed instances of Alation

Applies from Alation version 2025.1.3

Starting from Alation version 2025.1.3, you can use the unified source tags model to streamline source tag management in Alation.

The unified source tags model isn’t enabled by default and requires activation by Alation Support.

Important

Alation recommends keeping the unified source tags model enabled after it has been turned on. Note the following before enabling:

• Effect on existing custom Picker fields: If a custom Picker field in Alation shares a name with an extracted source tag, the two are merged into a single unified field during migration. After the merge, the Picker displays only the values defined in the source tag. Values that were part of the original Picker field but are not defined in the source tag will no longer appear as options in the Picker. Values already applied to catalog objects remain visible on those objects. For a detailed example, see Migrate to the Unified Source Tags Model.

• Migration cannot be undone: The migration transforms existing tag fields into unified fields. Alation recommends reviewing existing custom Picker fields for name matches with source tags and testing the migration in a staging environment before running it in production.

• Databricks Unity Catalog tags are read-only: Databricks Unity Catalog tags extracted through this model are read-only in Alation. You can view tag values and use them in search, but you cannot edit them or sync tag values from Alation to Databricks Unity Catalog.

Before You Begin

The source governs the definition and values of unified fields, so the unified source tags model suits some governance approaches better than others. Review whether it fits your governance before you enable it.

Use the unified source tags model when:

• You want a supported source system to be the authority for tag definitions and values.

• You want Alation to reflect source-defined metadata rather than maintain a separate definition.

• You need Databricks Unity Catalog tags in Alation, which are available only through this model.

• You want to reduce duplicate same-name source tags, including same-name Snowflake tags defined across schemas.

• Same-name tags across systems represent the same business concept.

• The teams that own the source tags and the catalog stewards work to a shared standard.

• You accept that source-controlled fields are not edited in Alation, and that Databricks Unity Catalog tags are read-only.

The unified source tags model may not suit you when:

• You want Alation to remain the authority for tag definitions and values, independent of the source.

• Stewards curate values in Alation that are intentionally different from the source values.

• Same-name fields represent different concepts in different systems.

• You expect to edit Databricks Unity Catalog tags from Alation.

• You depend on custom Picker field IDs in scripts, APIs, or reports without a plan for the change.

Note

You may try using Alation custom Picker fields, Snowflake-only source tag extraction, or distinctly named Alation fields instead. For Databricks Unity Catalog, tags are available only through the unified source tags model.

Before enabling the unified source tags model, review the following:

• Review existing custom Picker fields for name matches with source tags: Go to Admin Settings > Customize Catalog > Custom Fields > Pickers. Make a note of any fields whose names match tags defined in your Snowflake or Databricks Unity Catalog sources (case-insensitive). For each match, confirm whether the existing Picker field values and the source tag values are compatible. For details on merge behavior, see Understand Tag Ingestion in the Unified Source Tags Model.

• Confirm who maintains the source tags and whether catalog administrators have visibility into them: Source tags in Snowflake and Databricks Unity Catalog are maintained in the source system. If a source tag that shares a name with an Alation custom Picker field is maintained by a team that operates independently of the catalog administrators, confirm that the tag definitions and allowed values in the source are aligned with the values in the Alation Picker field before enabling. After unification, the allowed values in the unified Picker field will reflect those defined in the source tag. Changes to the source tag will be reflected in Alation after the next metadata extraction.

• Verify that source tags are defined as expected in the source system: Only tags applied to at least one object are extracted. Confirm that the tags you expect to see in Alation are defined and applied to objects in Snowflake or Databricks Unity Catalog before running metadata extraction.

• Review any scripts, API calls, or reports that reference custom Picker field IDs: Migration merges compatible custom Picker fields into a single unified field. If any scripts, webhooks, or reports reference the internal ID of a custom Picker field that is merged during migration, the original field ID may no longer return the expected results after migration. Before enabling, identify any such dependencies and verify them against the unified field after running the migration in a staging environment.

• Test in a staging environment before enabling in production: If you have an existing Alation instance with Snowflake tags extracted using the previous method, run the migration in a staging environment first. Review the resulting custom Picker fields and their values before proceeding to production.

How you enable the unified source tags model depends on whether you use Snowflake, Databricks Unity Catalog, or both and whether you’ve previously used Snowflake tag extraction:

• Enable Unified Source Tag Model for the First Time

• Manage Existing Tags

Enable Unified Source Tag Model for the First Time

Before enabling the unified source tags model, ensure you have the Snowflake, Databricks Unity Catalog, or both connectors of the following versions that support source tag extraction:

• Snowflake connector 2.8.0 or higher

• Databricks Databricks Unity Catalog connector version 3.2.0 or higher

If you are using older versions, consider upgrading your connectors. For details, see Upgrade Connector section in Manage Connectors. Once you have the right connector versions, you can proceed with enabling the feature.

Alation Cloud ServicesAlation Customer Managed

If you haven’t previously enabled and used tag extraction in Alation, contact Alation Support to start using the unified source tags model for your Snowflake, Databricks Unity Catalog, or for both these sources. Alation Support will enable the alation.feature_flags.DEV_enable_unified_tags feature flag upon request.

For information on how to create a Support case, see the Creating a new Alation Support Case section in Alation Support Portal.

After enabling the feature flag, an Alation Server Admin will activate the feature toggle in Admin Settings > Feature Configuration as described in Enable Source Tags in Alation.

Enable Source Tags in Alation

After Alation Support has enabled the unified source tags model, the Server Admin enables it in Admin Settings. Therefore to enable the unified source tags model, you must have the Server Admin role.

Note

To minimize disruption, we recommend enabling features during off-peak or non-working hours. After feature configurations are changed, active users will be prompted to refresh the browser page to apply the latest configuration. Refreshing the browser may cause any unsaved work to be lost.

To enable the unified source tags model:

1. Click the three gear icon in the top right corner to open the Admin Settings page.

2. Go to Feature Configuration:

   • In the New User Experience, under Customization, locate and open the Feature Configuration page or use the Search bar to locate and open it.

   • In the Classic User Experience, under the Sever Admin section, click Feature Configuration.

3. Scroll down to Enable Source Tags and turn on the toggle.

4. Scroll back to the top of the page and click Save changes.

5. In the dialog that appears, click Save Configuration. The page will refresh. Note that at this point, logged-in users will see a message prompting them to refresh their browser pages to apply the new configuration.

Once you have enabled the unified source tags feature, the next metadata extraction from Snowflake and Databricks Unity Catalog data sources will bring the source tags into the Alation catalog using the logic of the unified source tags model.

Note

The Enable Source Tags feature governs source tag extraction, ingestion, and synchronization. When the feature is on, tag values that you assign or change on Snowflake objects in Alation are synced back to Snowflake. Databricks Unity Catalog tags are read-only and are not synced from Alation. When the feature is off, Alation does not extract, display, or sync source tags.

For information on how to bring source tags into Alation next, see Bring Source Tags into Alation.

Manage Existing Tags

If your Alation catalog already contains Snowflake tags extracted using the previous method, you must migrate to the new unified source tag model to start using it. The migration converts your existing Snowflake tags, allowing you to use the unified source tags model with Snowflake, Databricks Unity Catalog, or both. Migrating to the unified source tags model enables you to eliminate limitations with managing tags previously.

For more details about the migration procedure, refer to Migrate to the Unified Source Tags Model.

Migrate to the Unified Source Tags Model

The migration transforms existing Snowflake tag fields and related Alation-specific fields into unified fields that follow the unified source tags model.

Warning

The migration can’t be undone. We recommend testing it in a staging environment before enabling it in production.

To verify that the migration was successful, before migration, review and make a list of the custom Picker fields associated with Snowflake tags and the catalog templates they are assigned to. You’ll need to review those fields and their template assignment after the migration also.

Contact Alation Support to migrate to the unified source tags model. The Support team runs the migration script upon request.

After the migration, tag fields still appear under Admin Settings > Customize Catalog > Custom Fields > Pickers. The script doesn’t rename or merge tag values.

The migration script converts existing Picker fields associated with Snowflake tags, and merges compatible Alation-specific Picker fields with matching names, into unified fields that follow the unified source tags model. If a Snowflake tag and an Alation-specific Picker field have the same name and compatible allowed values, they are merged into a single unified field. The Picker field will display only Snowflake-defined values going forward, but any previously applied Alation-specific values will remain visible on objects where they were previously applied.

Consider the following example to understand how the migration to the unified source tags model works.

Let’s assume that your Catalog Admin created a custom Picker field INDUSTRY with values OIL, TECH, FINANCE, HEALTHCARE and manually applied these values to table catalog pages, including:

• Tables in a PostgreSQL data source

• Tables in a Databricks Unity Catalog data source

At the same time, a schema named market_schema in a Snowflake data source defines a tag INDUSTRY with values: OIL, TECH. The tag was previously extracted into Alation and appears as a Snowflake tag Picker field on the catalog pages of Snowflake tables in this schema.

Currently, this Snowflake tag duplicates the Picker field INDUSTRY applied across a number of other data sources.

The migration to the unified source tags model will result in the following changes:

• Merge behavior: The two separate INDUSTRY Picker fields are merged into a unified field because:

  • The names are the same.

  • The allowed values are compatible (OIL, TECH).

• Unified Pickers field display:

  • The Admin Settings > Customize Catalog > Custom Fields > Pickers tag fields display values:

    • OIL (origin: Snowflake + Alation)

    • TECH (origin: Snowflake + Alation)

  • The following values are not displayed as they are not originating from the Snowflake data source

    • FINANCE (retained on catalog object page where it was already applied).

    • HEALTHCARE (retained on catalog object page where it was already applied).

• Object catalog page display:

  • PostgreSQL tables - INDUSTRY field is displayed with values:

    • FINANCE and HEALTHCARE, or both if they were previously applied.

    • OIL and TECH.

  • Snowflake tables - INDUSTRY field shows:

    • OIL and TECH (Snowflake origin).

  • Databricks tables - INDUSTRY field is displayed with values:

    • FINANCE and HEALTHCARE or both if they were previously applied.

    • OIL and TECH.

Consider another example where a user has defined two custom Picker fields in Alation with the same name PII.

• PII with values Yes, No

• PII with True, False

And both these Picker fields PII are applied on a tableA in Postgres data source with value as Yes and True.

After migration to the unified source tags model, Alation will have a unified custom field PII with values Yes, No, True, False and the tableA in Postgres asset will show a concatenated value Yes, True or True, Yes.

Therefore, migrating duplicate Alation-specific fields preserves all previously applied values from both fields, which are displayed as a concatenation.

Once the migration is complete and you have verified its success by reviewing Picker fields to confirm all values exist and are correctly applied, the unified source tags model is fully active. Subsequent metadata extractions from Snowflake and Databricks Unity Catalog will utilize this new model for tag ingestion given that you have the required connector versions.

For more examples, refer to Understand Tag Ingestion in the Unified Source Tags Model.