Google Cloud Professional Data Engineer Exam

When processing large datasets together with small, frequently changing data, what is the key advantage of using federated queries in BigQuery?

1. They permanently copy data from the source

2. They leverage real-time data access without duplication

3. They improve query speed significantly

4. They compress large datasets efficiently

The correct answer is: They leverage real-time data access without duplication

The key advantage of using federated queries in BigQuery is that they leverage real-time data access without duplication. This means that when dealing with large datasets alongside smaller, frequently changing datasets, federated queries allow you to query the data in its original location rather than requiring a complete copy of the data to be made in BigQuery. This capability is particularly beneficial in scenarios where data is constantly changing, as it enables you to access the most current data without the overhead of maintaining duplicates. For example, if the small dataset is updated frequently (like logs or user-generated content), using a federated query allows you to always pull the latest version for analysis while still being able to run it against larger, more stable datasets that may reside in BigQuery. This real-time access is essential for prompt decision-making and insights, especially in environments where up-to-date information is critical, such as in analytics for advertising or financial data. Thus, the use of federated queries simplifies the data processing workflow and reduces the complexities associated with data synchronization.