In which of the following file formats is data from Delta Lake tables primarily stored?

1. A. Delta
2. B. CSV
3. C. Parquet
4. D. JSON
5. E. A proprietary, optimized format specific to Databricks

Correct Answer: C
https://docs.delta.io/latest/delta-faq.html

A data engineer has realized that they made a mistake when making a daily update to a table. They need to use Delta time travel to restore the table to a version that is 3 days old. However, when the data engineer attempts to time travel to the older version, they are unable to restore the data because the data files have been deleted.
Which of the following explains why the data files are no longer present?

1. A. The VACUUM command was run on the table
2. B. The TIME TRAVEL command was run on the table
3. C. The DELETE HISTORY command was run on the table
4. D. The OPTIMIZE command was nun on the table
5. E. The HISTORY command was run on the table

Correct Answer: A
The VACUUM command in Delta Lake is used to clean up and remove unnecessary data files that are no longer needed for time travel or query purposes. When you run VACUUMwith certain retention settings, it can delete older data files, which might include versions of data that are older than the specified retention period. If the data engineer is unable to restore the table to a version that is 3 days old because the data files have been deleted, it's likely because the VACUUM command was run on the table, removing the older data files as part of data cleanup.

Which of the following describes the relationship between Bronze tables and raw data?

1. A. Bronze tables contain less data than raw data files.
2. B. Bronze tables contain more truthful data than raw data.
3. C. Bronze tables contain aggregates while raw data is unaggregated.
4. D. Bronze tables contain a less refined view of data than raw data.
5. E. Bronze tables contain raw data with a schema applied.

Correct Answer: E
The Bronze layer is where we land all the data from external source systems. The table structures in this layer correspond to the source system table structures "as-is," along with any additional metadata columns that capture the load date/time, process ID, etc. The focus in this layer is quick Change Data Capture and the ability to provide an historical archive of source (cold storage), data lineage, auditability, reprocessing if needed without rereading the data from the source system.https://www.databricks.com/glossary/medallion- architecture#:~:text=Bronze%20layer%20%28raw%20data%29

A data engineering team has noticed that their Databricks SQL queries are running too slowly when they are submitted to a non-running SQL endpoint. The data engineering team wants this issue to be resolved.
Which of the following approaches can the team use to reduce the time it takes to return results in this scenario?

1. A. They can turn on the Serverless feature for the SQL endpoint and change the Spot Instance Policy to "Reliability Optimized."
2. B. They can turn on the Auto Stop feature for the SQL endpoint.
3. C. They can increase the cluster size of the SQL endpoint.
4. D. They can turn on the Serverless feature for the SQL endpoint.
5. E. They can increase the maximum bound of the SQL endpoint's scaling range

Correct Answer: C
https://www.databricks.com/blog/2022/03/10/top-5-databricks-performance- tips.html

A data engineer wants to create a data entity from a couple of tables. The data entity must be used by other data engineers in other sessions. It also must be saved to a physical location.
Which of the following data entities should the data engineer create?

1. A. Database
2. B. Function
3. C. View
4. D. Temporary view
5. E. Table

Correct Answer: E
In the context described, creating a "Table" is the most suitable choice. Tables in SQL are data entities that exist independently of any session and are saved in a physical location. They can be accessed and manipulated by other data engineers in different sessions, which aligns with the requirements stated. A "Database" is a collection of tables, views, and other database objects. A "Function" is a stored procedure that performs an operation. A "View" is a virtual table based on the result-set of an SQL statement, but it is not stored physically. A "Temporary view" is a feature that allows you to store the result of a query as a view that disappears once your session with the database is closed.