Identify Delta Table Maintenance with DESCRIBE HISTORY

DP-600 By islever Editorial Last updated

Maintain the analytics development lifecycle

Short answer

A Running DESCRIBE HISTORY customer identifies whether maintenance tasks like OPTIMIZE and VACUUM 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: DESCRIBE HISTORY customer - Does this meet the goal?
  1. Yes Correct Answer
  2. No

Key Takeaways

The DESCRIBE HISTORY command exposes the transaction log of a Delta table, allowing you to verify if optimization or vacuum operations have been executed.

Running DESCRIBE HISTORY on a Delta table in Microsoft Fabric reveals its operation history, including maintenance tasks like OPTIMIZE and VACUUM. This confirms that the statement meets the goal of identifying whether maintenance was performed.

Common mistake: Assuming DESCRIBE HISTORY only shows data manipulation operations (like inserts or updates) and not table maintenance commands like OPTIMIZE or VACUUM.

Expert Analysis

Why the Answer Is Correct

The DESCRIBE HISTORY command returns provenance information, including operations, for a Delta table. Maintenance tasks such as OPTIMIZE and VACUUM are logged as operations in the Delta transaction log. Therefore, running this statement successfully identifies whether these maintenance tasks have been performed on the Customer table.

Why the Other Options Are Wrong

Option B is incorrect because it assumes the statement does not meet the goal. In reality, the Delta Lake transaction log captures all table changes and maintenance events, making DESCRIBE HISTORY a valid method to check for them.

Community Comment Notes

Community members agree that DESCRIBE HISTORY meets the goal because "OPTIMIZE and VACUUM activities in the last 30 days are stored in the history." As stilferx noted, the official documentation confirms this capability for Delta tables.

Official Reference

https://learn.microsoft.com/en-us/azure/databricks/delta/history

This link opens the official vendor documentation in a new tab.

Exam Strategy

When asked how to check Delta table maintenance or history, look for commands that interact with the Delta transaction log, such as DESCRIBE HISTORY or DESCRIBE DETAIL. Remember that OPTIMIZE and VACUUM operations are recorded in the history.

Community Votes

A
100%

100% of anonymous learners picked answer A. 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. stilferx 👍 4 Answered A
    IMHO, A Link: https://learn.microsoft.com/en-us/azure/databricks/delta/history
  2. Martin_Nbg 👍 3
    OPTIMIZE and VACUUM activities in the last 30 days are stored in the history. So, yes, you can see using this query whether maintenance took place in the last 30 days. https://learn.microsoft.com/en-us/azure/databricks/delta/history
  3. 282b85d 👍 3 Answered A
    Yes, running DESCRIBE HISTORY customer meets the goal of identifying whether maintenance tasks were performed on the Delta table.
  4. a_51 👍 2 Answered A
    A correct. display(spark.sql('describe history customer'))
  5. XiltroX 👍 2 Answered A
    Right answer. Describe HISTORY
Show 1 more comment
  1. Momoanwar 👍 2 Answered A
    Correct

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