Data Freshness Check
Quickly determine if data is fresh enough to use.
Freshness Check Process
For each table to check:
1. Find the Timestamp Column
Look for columns that indicate when data was loaded or updated:
_loaded_at,_updated_at,_created_at(common ETL patterns)updated_at,created_at,modified_at(application timestamps)load_date,etl_timestamp,ingestion_timedate,event_date,transaction_date(business dates)
Query INFORMATION_SCHEMA.COLUMNS if you need to see column names.
2. Query Last Update Time
SELECT
MAX(<timestamp_column>) as last_update,
CURRENT_TIMESTAMP() as current_time,
TIMESTAMPDIFF('hour', MAX(<timestamp_column>), CURRENT_TIMESTAMP()) as hours_ago,
TIMESTAMPDIFF('minute', MAX(<timestamp_column>), CURRENT_TIMESTAMP()) as minutes_ago
FROM <table>3. Check Row Counts by Time
For tables with regular updates, check recent activity:
SELECT
DATE_TRUNC('day', <timestamp_column>) as day,
COUNT(*) as row_count
FROM <table>
WHERE <timestamp_column> >= DATEADD('day', -7, CURRENT_DATE())
GROUP BY 1
ORDER BY 1 DESCFreshness Status
Report status using this scale:
| Status | Age | Meaning |
|---|---|---|
| Fresh | < 4 hours | Data is current |
| Stale | 4-24 hours | May be outdated, check if expected |
| Very Stale | > 24 hours | Likely a problem unless batch job |
| Unknown | No timestamp | Can't determine freshness |
If Data is Stale
Check Airflow for the source pipeline:
- Find the DAG: Which DAG populates this table? Use
af dags listand look for matching names. - Check DAG status:
- Is the DAG paused? Use af dags get <dag_id> - Did the last run fail? Use af dags stats - Is a run currently in progress?
- Diagnose if needed: If the DAG failed, use the debugging-dags skill to investigate.
On Astro
If you're running on Astro, you can also:
- DAG history in the Astro UI: Check the deployment's DAG run history for a visual timeline of recent runs and their outcomes
- Astro alerts for SLA monitoring: Configure alerts to get notified when DAGs miss their expected completion windows, catching staleness before users report it
On OSS Airflow
- Airflow UI: Use the DAGs view and task logs to verify last successful runs and SLA misses
Output Format
Provide a clear, scannable report:
FRESHNESS REPORT
================
TABLE: database.schema.table_name
Last Update: 2024-01-15 14:32:00 UTC
Age: 2 hours 15 minutes
Status: Fresh
TABLE: database.schema.other_table
Last Update: 2024-01-14 03:00:00 UTC
Age: 37 hours
Status: Very Stale
Source DAG: daily_etl_pipeline (FAILED)
Action: Investigate with **debugging-dags** skillQuick Checks
If user just wants a yes/no answer:
- "Is X fresh?" -> Check and respond with status + one line
- "Can I use X for my 9am meeting?" -> Check and give clear yes/no with context