Exam DP-750 Topic 1 Question 21 Discussion

Actual exam question for Microsoft's DP-750 exam
Question #: 21
Topic #: 1
You have an Azure Databricks workspace that contains a Delta table named Customer.
A job named Job1 performs frequent upserts into Customer.
You discover that Job1 has created many small Parquet files in Customer, and the small files are degrading query performance.
You need to improve query performance for the current data already stored in Customer. The solution must not affect the travel for the Customer table.
What should you do?

Suggested Answer: B Vote an answer

The OPTIMIZE command performs bin-packing compaction, combining the Customer table's existing small Parquet files into fewer, larger files. This reduces file-open overhead and improves data-skipping efficiency without changing the logical table contents. Enabling optimized writes affects future write operations but does not compact the small files already stored. VACUUM removes unreferenced data files that are older than the configured retention threshold; it does not reorganize active small files and can restrict time-travel availability. Reducing delta.deletedFileRetentionDuration changes how long obsolete files remain available and can directly reduce the time-travel window, contrary to the requirement. OPTIMIZE is therefore the correct operation for improving the physical layout of current data while preserving Delta table semantics and history. Microsoft Learn

by Denise at Aug 21, 2026, 01:44 AM

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