Tracing Downstream Lineage

Downstream Lineage: Impacts

Answer the question: "What breaks if I change this?"

Impact Analysis

Step 1: Identify Direct Consumers

For tables:

1. List DAGs using list_active_dags and list_paused_dags
2. Search DAG source using get_dag_source_code for table references

For DAGs:

1. Determine outputs from DAG source
2. Trace consumer DAGs that read those outputs

Step 2: Build Dependency Tree

Example:

SOURCE: fct.orders
    |
    +-- TABLE: agg.daily_sales -> Dashboard: Executive KPIs
    +-- TABLE: ml.order_features -> Model: Forecasting

Step 3: Categorize by Criticality

• Critical: production dashboards, customer-facing apps
• High: internal ops dashboards, downstream ETL
• Medium: ad-hoc analysis
• Low: deprecated or test data

Step 4: Assess Change Risk

Consider:

• Schema changes
• Data timing changes
• Deletion or deprecation

Step 5: Find Stakeholders

• DAG owners in DAG definitions
• Dashboard owners in BI tools

Output: Impact Report

Include:

• Summary of downstream assets
• Impact diagram
• Detailed impacts and owners
• Risk assessment and mitigations

Related Skills

• tracing-upstream-lineage
• checking-freshness
• debugging-dags
• annotating-task-lineage
• creating-openlineage-extractors