Tags Not Applying to Datasets or Columns

Tags added through the UI, API, or ingestion are not appearing on datasets or columns, or they disappear after subsequent ingestion runs. This commonly occurs due to incorrect tag URN format, insufficient permissions, or tags being overwritten by ingestion.

You Might Be Asking:

• Why aren't my tags showing up in DataHub?
• How do I prevent ingestion from removing manually added tags?
• What's the correct format for tag URNs?

1. Verify tag URN format is correct:

# Correct format:
urn:li:tag:YourTagName

# NOT:
YourTagName (missing URN prefix)
urn:li:tags:YourTagName (wrong entity type)

2. Add tags via GraphQL API:

mutation addTags {
  addTags(
    input: {
      tagUrns: ["urn:li:tag:PII", "urn:li:tag:Sensitive"],
      resourceUrn: "urn:li:dataset:(urn:li:dataPlatform:snowflake,db.schema.table,PROD)"
    }
  )
}

3. Configure ingestion to preserve manual tags:

source:
  config:
    # Don't override existing tags
    tags:
      override: false
    # Or use transformers to add tags conditionally
    transformers:
      - type: "pattern_add_dataset_tags"
        config:
          tag_urns: ["urn:li:tag:AutoGenerated"]

4. Check user permissions for tagging:

   • Ensure the user has "Edit Tags" privilege
   • Check policy rules allow tag modifications

5. For column-level tags, use editableSchemaMetadata:

Example for Snowflake. This can be adapted for other data sources/connectors.

from datahub.emitter.mce_builder import make_dataset_urn, make_tag_urn
from datahub.metadata.schema_classes import EditableSchemaMetadataClass

dataset_urn = make_dataset_urn("snowflake", "db.schema.table")
editable_schema_metadata = EditableSchemaMetadataClass(
    editableSchemaFieldInfo=[
        EditableSchemaFieldInfoClass(
            fieldPath="column_name",
            globalTags=GlobalTagsClass(
                tags=[TagAssociationClass(tag=make_tag_urn("PII"))]
            )
        )
    ]
)

Tags added during ingestion with override: true will replace manually added tags. Use transformers or post-processing scripts to combine tags from multiple sources.

• Tags Guide
• GraphQL Tags API