DP-700 Monitor and Optimize an Analytics Solution Practice Question
You notice that your Delta table is experiencing slow read performance due to file fragmentation. Which command should you run to optimize the physical storage layout?
⚠ Common exam trap
Candidates often choose 'VACUUM' instead of 'OPTIMIZE'. VACUUM deletes old files to save space, whereas OPTIMIZE merges small files into larger ones to fix performance issues caused by fragmentation.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
OPTIMIZE TABLE
The OPTIMIZE command is the standard Delta Lake operation to compact small files into larger, optimally sized files. This reduces the metadata overhead and allows for more efficient sequential reads. In Fabric, running this periodically is a core maintenance task that ensures high-performance analytics, as it directly addresses the 'small file problem' that frequently impacts Lakehouse performance when data is ingested in high-frequency, low-volume batches.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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REORG TABLE
Why it's wrong here
REORG TABLE is used for specific data reorganization tasks like rewriting files for column mapping or deletion vectors. While helpful, it is not the primary command for general file compaction and performance optimization in Delta Lake; the OPTIMIZE command is the standard tool for this specific purpose.
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VACUUM TABLE
Why it's wrong here
VACUUM removes old, orphaned data files that are no longer referenced by the Delta log. While important for storage cleanup and cost management, it does not rearrange the current data into larger files, meaning it provides no benefit for read performance related to file fragmentation.
- ✓
OPTIMIZE TABLE
Why this is correct
The OPTIMIZE command is specifically designed to compact small Delta files into larger files. This process significantly improves read performance by reducing the metadata volume and enabling more efficient disk I/O, which is essential for maintaining query speed in tables that undergo frequent updates or high-frequency ingestion.
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ANALYZE TABLE
Why it's wrong here
ANALYZE is used to update table statistics, which helps the query optimizer generate better execution plans. While valuable, it does not physically rewrite the files on disk to consolidate fragments. Therefore, it will not resolve performance issues caused by a high number of small files.
About these practice questions
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Microsoft exam blueprint
This DP-700 practice question is part of Courseiva's free Microsoft certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DP-700 exam.