🗓️ 07082025 1038
Data Federation is the technique of querying and integrating data from multiple, distributed sources (databases, data lakes, APIs, etc.) as if they were a single source — without physically moving or copying the data.
🛠️ How It Works (High-Level)
Instead of ETL-ing all data into one place:
- A federated engine sits on top of the data sources
 - When a query comes in, it:
- Breaks it into subqueries
 - Sends subqueries to each data source
 - Aggregates the results
 - Returns a unified response
 
 
💼 When to Use It
| Use Case | Why Data Federation Helps | 
|---|---|
| Data is spread across services/databases | Avoids centralization or duplication | 
| Need fast insights across systems | Real-time querying without pre-aggregation | 
| Can't move data due to compliance | Leaves data in-place (good for GDPR etc.) | 
✅ Pros
- No need to duplicate data
 - Real-time / near real-time access
 - Flexible for ad-hoc queries
 - Good for hybrid/multi-cloud environments
 
⚠️ Cons
- Performance depends on underlying sources
 - Complexity in query planning and optimization
 - Limited joins across incompatible systems
 - Latency can be high if sources are slow or far apart
 
🔍 Examples of Data Federation Tools
| Tool / Platform | Description | 
|---|---|
| Presto / Trino | Open-source distributed SQL query engine | 
| Google BigQuery Federation | Query Cloud SQL, GCS, Sheets from BigQuery | 
| Athena Federated Queries | Query multiple AWS sources | 
| Denodo | Enterprise data virtualization platform | 
| Starburst | Commercial Presto/Trino offering | 
References
- ChatGPT