Using EXPLAIN vs DESCRIBE HISTORY for Delta Table Maintenance

DP-600 By islever Editorial Last updated

Maintain the analytics development lifecycle

Short answer

B Running EXPLAIN TABLE customer only displays the query execution plan and does not identify whether maintenance tasks were performed.

Question

Note: This question is part of a series of questions that present the same scenario. Each question in the series contains a unique solution that might meet the stated goals. Some question sets might have more than one correct solution, while others might not have a correct solution. After you answer a question in this section, you will NOT be able to return to it. As a result, these questions will not appear in the review screen. You have a Fabric tenant that contains a lakehouse named Lakehouse1. Lakehouse1 contains a Delta table named Customer. When you query Customer, you discover that the query is slow to execute. You suspect that maintenance was NOT performed on the table. You need to identify whether maintenance tasks were performed on Customer. Solution: You run the following Spark SQL statement: EXPLAIN TABLE customer - Does this meet the goal?
  1. Yes
  2. No Correct Answer

Key Takeaways

This question tests the difference between Spark SQL execution plan commands and Delta Lake history commands; the common trap is confusing EXPLAIN with DESCRIBE HISTORY.

The EXPLAIN statement in Spark SQL is used to display the execution plan of a query, not the maintenance history of a Delta table. This page establishes that using EXPLAIN does not meet the goal of identifying past maintenance tasks.

Common mistake: Choosing 'Yes' because EXPLAIN sounds like it would explain the table's status or history, but it actually only shows query execution plans.

Expert Analysis

Why the Answer Is Correct

The correct answer is B (No) because the EXPLAIN statement in Spark SQL is designed to display the logical and physical execution plans for a query. It does not provide any historical metadata about maintenance operations like OPTIMIZE or VACUUM that have been executed on the Delta table. Therefore, it cannot identify whether maintenance tasks were performed.

Why the Other Options Are Wrong

Option A (Yes) is incorrect because it assumes EXPLAIN reveals table maintenance history or status. To actually view the history of operations performed on a Delta table, the correct command is DESCRIBE HISTORY, not EXPLAIN. Relying on EXPLAIN would leave you without the necessary information to resolve the suspected maintenance issue.

Community Comment Notes

As user 282b85d noted, "The EXPLAIN statement in Spark SQL is used to display the execution plan of a query... it does not provide historical information about maintenance tasks". Furthermore, user XiltroX correctly pointed out that the appropriate command to meet the goal is "DESCRIBE HISTORY customer".

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

Know the specific Spark SQL and Delta Lake utility commands used for diagnostics and maintenance. EXPLAIN is strictly for query plans, while DESCRIBE HISTORY is for Delta table operation logs. Memorizing these distinct command purposes prevents confusion on the exam.

Community Votes

B
100%

100% of anonymous learners picked answer B. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 6 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors, not of islever. The comments shown first are the most substantive of the thread — ranked by depth, community endorsement and relevance; expand the list below to read the rest.

From public community threads 6

  1. 282b85d 👍 7 Answered B
    The EXPLAIN statement in Spark SQL is used to display the execution plan of a query. This plan shows how Spark will execute the query, including details about the operations and stages involved. While it is useful for understanding and optimizing query performance, it does not provide historical information about maintenance tasks like optimization, compaction, or vacuuming performed on the table.
  2. XiltroX 👍 2 Answered B
    Correct answer is DESCRIBE HISTORY customer. Good luck everyone.
  3. Momoanwar 👍 2 Answered B
    Given answer is correct. Explain is for query execution plan
  4. wellingtonluis 👍 2 Answered B
    Good luck !!!
  5. stilferx 👍 1 Answered B
    IMHO, NOOOO
Show 1 more comment
  1. earlqq 👍 1
    Correct

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