Online Access Free Databricks-Certified-Data-Engineer-Professional Practice Test

A data engineer wants to join a stream of advertisement impressions (when an ad was shown) with another stream of user clicks on advertisements to correlate when impressions led to monetizable clicks.
In the code below, Impressions is a streaming DataFrame with a watermark ("event_time", "10 minutes")

The data engineer notices the query slowing down significantly.
Which solution would improve the performance?

• A.Joining on event time constraint: clickTime >= impressionTime - interval 3 hours and removing watermarks
• B.Joining on event time constraint: clickTime >= impressionTime AND clickTime <= impressionTime interval 1 hour
• C.Joining on event time constraint: clickTime == impressionTime using a leftOuter join
• D.Joining on event time constraint: clickTime + 3 hours < impressionTime - 2 hours

When a new Databricks project starts, the central IP team provisions the required infrastructure using Terraform and a Service Principal. This includes creating a Databricks workspace, a Unity Catalog linked to an External Location, and a Databricks group containing all project team members. Project teams must store all assets - e.g., tables and volumes, as Managed assets in Unity Catalog. This model hides infrastructure complexity while giving teams autonomy within their catalog. They can create and manage schemas, tables, volumes, and related objects but cannot rename, delete, or change catalog permissions, those remain under IT's control. Which rights should the project group be granted to enable this model?

• A.The group needs to have USE CATALOG and USE SCHEMA on the catalog.
• B.The group should be made OWNER of the catalog.
• C.The group needs to have ALL PRIVILEGES on the catalog.
• D.The group needs to have ALL PRIVILEGES and the MANAGE on the catalog.

A user wants to use DLT expectations to validate that a derived table report contains all records from the source, included in the table validation_copy.
The user attempts and fails to accomplish this by adding an expectation to the report table definition.

Which approach would allow using DLT expectations to validate all expected records are present in this table?

• A.Define a temporary table that perform a left outer join on validation_copy and report, and define an expectation that no report key values are null
• B.Define a view that performs a left outer join on validation_copy and report, and reference this view in DLT expectations for the report table
• C.Define a function that performs a left outer join on validation_copy and report and report, and check against the result in a DLT expectation for the report table
• D.Define a SQL UDF that performs a left outer join on two tables, and check if this returns null values for report key values in a DLT expectation for the report table.

The data engineer is using Spark's MEMORY_ONLY storage level. Which indicators should the data engineer look for in the spark UI's Storage tab to signal that a cached table is not performing optimally?

• A.The number of Cached Partitions> the number of Spark Partitions
• B.Size on Disk is < Size in Memory
• C.Size on Disk is> 0
• D.The RDD Block Name included the '' annotation signaling failure to cache
• E.On Heap Memory Usage is within 75% of off Heap Memory usage

A departing platform owner currently holds ownership of multiple catalogs and controls storage credentials and external locations. A data engineer has been asked to ensure continuity: transfer catalog ownership to the platform team group, delegate ongoing privilege management, and retain the ability to receive and share data via Delta Sharing. Which role must be in place to perform these actions across the metastore?

• A.Workspace Admin, because workspace admins can transfer ownership of any Unity Catalog object.
• B.Account Admin, because account admins can only create metastores but cannot change ownership of catalogs.
• C.Metastore Admin, because metastore admins can transfer ownership and manage privileges across all metastore objects, including shares and recipients.
• D.Catalog Owner, because catalog owners can transfer any object in any catalog in the metastore.