Databricks Data Engineer Professional exam dumps

Databricks Data Engineer Professional practice question 31 of 313

Databricks Certified Data Engineer Professional. Professional level, Databricks. Free question with the correct answer and a full explanation.

Databricks Data Engineer Professional Question 31

Select 3

You are designing a Delta table to optimize query performance in the Databricks SQL service. The table will handle a high volume of analytical queries with frequent aggregations and filtering on a 'region' column. Which of the following steps should you take to ensure the Delta table is optimized for this workload?

  1. A

    Enable Z-Ordering on the 'region' column.

  2. B

    Partition the table by the 'region' column.

  3. C

    Set the Delta table's vacuum retention period to 1 hour.

  4. D

    Use the OPTIMIZE command after major data loads.

  5. E

    Store the Delta table in JSON format.

  6. F

    Disable Delta table versioning to reduce metadata size.

Show answer and explanation

Correct answers: A, B, D

Explanation

To optimize a Delta table for Databricks SQL service, you should leverage Z-Ordering for columns frequently used in filtering, such as 'region'. Partitioning by the 'region' column can further enhance performance by reducing the amount of data scanned during queries. Additionally, using the OPTIMIZE command after major data loads compacts files, reducing the query overhead. These steps collectively ensure the Delta table is optimized for analytical workloads.

  • A. Correct.

    Z-Ordering helps optimize query performance for columns frequently used in filtering, such as 'region'.

  • B. Correct.

    Partitioning the table by the 'region' column can significantly improve query performance for analytical workloads where 'region' is used in filtering.

  • C. Incorrect.

    Setting a vacuum retention period to 1 hour is unrelated to query performance optimization and could lead to data loss if not handled carefully.

  • D. Correct.

    The OPTIMIZE command compacts small files into larger ones, improving query performance for analytical workloads in Delta tables.

  • E. Incorrect.

    Storing the Delta table in JSON format is not recommended as Delta tables are optimized for Parquet storage.

  • F. Incorrect.

    Disabling Delta table versioning is not possible and would negate the ACID properties and time-travel benefits of Delta tables.

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