Databricks DATABRICKS-CERTIFIED-PROFESSIONAL-DATA-ENGINEER Online Practice Questions and Exam Preparation

Databricks DATABRICKS-CERTIFIED-PROFESSIONAL-DATA-ENGINEER Online Questions & Answers

• Question 81:

  A data team's Structured Streaming job is configured to calculate running aggregates for item sales to update a downstream marketing dashboard. The marketing team has introduced a new field to track the number of times this promotion code is used for each item. A junior data engineer suggests updating the existing query as follows: Note that proposed changes are in bold.

  Original query:

  

  Proposed query:

  

  Which step must also be completed to put the proposed query into production?

  A. Increase the shuffle partitions to account for additional aggregates
  B. Specify a new checkpointlocation
  C. Run REFRESH TABLE delta, /item_agg'
  D. Remove .option (mergeSchema', true') from the streaming write
  B. Specify a new checkpointlocation

• Question 82:

  Which statement describes integration testing?

  A. Validates interactions between subsystems of your application
  B. Requires an automated testing framework
  C. Requires manual intervention
  D. Validates an application use case
  E. Validates behavior of individual elements of your application
  A. Validates interactions between subsystems of your application

• Question 83:

  The security team is exploring whether or not the Databricks secrets module can be leveraged for connecting to an external database.

  After testing the code with all Python variables being defined with strings, they upload the password to the secrets module and configure the correct permissions for the currently active user. They then modify their code to the following (leaving all other variables unchanged).

  

  Which statement describes what will happen when the above code is executed?

  A. The connection to the external table will fail; the string "redacted" will be printed.
  B. An interactive input box will appear in the notebook; if the right password is provided, the connection will succeed and the encoded password will be saved to DBFS.
  C. An interactive input box will appear in the notebook; if the right password is provided, the connection will succeed and the password will be printed in plain text.
  D. The connection to the external table will succeed; the string value of password will be printed in plain text.
  E. The connection to the external table will succeed; the string "redacted" will be printed.
  E. The connection to the external table will succeed; the string "redacted" will be printed.

• Question 84:

  A CHECK constraint has been successfully added to the Delta table named activity_details using the following logic:

  

  A batch job is attempting to insert new records to the table, including a record where latitude = 45.50 and longitude = 212.67.

  Which statement describes the outcome of this batch insert?

  A. The write will fail when the violating record is reached; any records previously processed will be recorded to the target table.
  B. The write will fail completely because of the constraint violation and no records will be inserted into the target table.
  C. The write will insert all records except those that violate the table constraints; the violating records will be recorded to a quarantine table.
  D. The write will include all records in the target table; any violations will be indicated in the boolean column named valid_coordinates.
  E. The write will insert all records except those that violate the table constraints; the violating records will be reported in a warning log.
  B. The write will fail completely because of the constraint violation and no records will be inserted into the target table.

• Question 85:

  The data science team has requested assistance in accelerating queries on free form text from user reviews. The data is currently stored in Parquet with the below schema:

  item_id INT, user_id INT, review_id INT, rating FLOAT, review STRING

  The review column contains the full text of the review left by the user. Specifically, the data science team is looking to identify if any of 30 key words exist in this field.

  A junior data engineer suggests converting this data to Delta Lake will improve query performance.

  Which response to the junior data engineer s suggestion is correct?

  A. Delta Lake statistics are not optimized for free text fields with high cardinality.
  B. Text data cannot be stored with Delta Lake.
  C. ZORDER ON review will need to be run to see performance gains.
  D. The Delta log creates a term matrix for free text fields to support selective filtering.
  E. Delta Lake statistics are only collected on the first 4 columns in a table.
  A. Delta Lake statistics are not optimized for free text fields with high cardinality.

• Question 86:

  A table is registered with the following code: Bothusersandordersare Delta Lake tables. Which statement describes the results of queryingrecent_orders?

  

  A. All logic will execute at query time and return the result of joining the valid versions of the source tables at the time the query finishes.
  B. All logic will execute when the table is defined and store the result of joining tables to the DBFS; this stored data will be returned when the table is queried.
  C. Results will be computed and cached when the table is defined; these cached results will incrementally update as new records are inserted into source tables.
  D. All logic will execute at query time and return the result of joining the valid versions of the source tables at the time the query began.
  E. The versions of each source table will be stored in the table transaction log; query results will be saved to DBFS with each query.
  B. All logic will execute when the table is defined and store the result of joining tables to the DBFS; this stored data will be returned when the table is queried.

• Question 87:

  Incorporating unit tests into a PySpark application requires upfront attention to the design of your jobs, or a potentially significant refactoring of existing code. Which statement describes a main benefit that offset this additional effort?

  A. Improves the quality of your data
  B. Validates a complete use case of your application
  C. Troubleshooting is easier since all steps are isolated and tested individually
  D. Yields faster deployment and execution times
  E. Ensures that all steps interact correctly to achieve the desired end result
  C. Troubleshooting is easier since all steps are isolated and tested individually

• Question 88:

  An upstream source writes Parquet data as hourly batches to directories named with the current date. A nightly batch job runs the following code to ingest all data from the previous day as indicated by thedatevariable:

  

  Assume that the fieldscustomer_idandorder_idserve as a composite key to uniquely identify each order.

  If the upstream system is known to occasionally produce duplicate entries for a single order hours apart, which statement is correct?

  A. Each write to the orders table will only contain unique records, and only those records without duplicates in the target table will be written.
  B. Each write to the orders table will only contain unique records, but newly written records may have duplicates already present in the target table.
  C. Each write to the orders table will only contain unique records; if existing records with the same key are present in the target table, these records will be overwritten.
  D. Each write to the orders table will only contain unique records; if existing records with the same key are present in the target table, the operation will tail.
  E. Each write to the orders table will run deduplication over the union of new and existing records, ensuring no duplicate records are present.
  B. Each write to the orders table will only contain unique records, but newly written records may have duplicates already present in the target table.

• Question 89:

  A Delta Lake table was created with the below query:

  

  Realizing that the original query had a typographical error, the below code was executed:

  ALTER TABLE prod.sales_by_stor RENAME TO prod.sales_by_store

  Which result will occur after running the second command?

  A. The table reference in the metastore is updated and no data is changed.
  B. The table name change is recorded in the Delta transaction log.
  C. All related files and metadata are dropped and recreated in a single ACID transaction.
  D. The table reference in the metastore is updated and all data files are moved.
  E. A new Delta transaction log Is created for the renamed table.
  A. The table reference in the metastore is updated and no data is changed.

• Question 90:

  A production cluster has 3 executor nodes and uses the same virtual machine type for the driver and executor.

  When evaluating the Ganglia Metrics for this cluster, which indicator would signal a bottleneck caused by code executing on the driver?

  A. The five Minute Load Average remains consistent/flat
  B. Bytes Received never exceeds 80 million bytes per second
  C. Total Disk Space remains constant
  D. Network I/O never spikes
  E. Overall cluster CPU utilization is around 25%
  E. Overall cluster CPU utilization is around 25%