Databricks Data Engineer Associate · 10% practice allocation
5 free sample questions from the Troubleshooting, Monitoring, and Optimization domain, with answers and explanations. The full Data Engineer Associate bank has 300 questions across 7 domains. Questions are scenario-based and written from the official Databricks exam guide.
Which command permanently removes data files no longer referenced by a Delta table (respecting the retention window) to reclaim storage?
VACUUM deletes files no longer referenced by the table beyond the retention threshold, reclaiming storage. OPTIMIZE (B) compacts, MERGE (D) upserts, and CREATE TABLE (C) makes a table.
A streaming ingest has produced millions of tiny files, slowing queries. Which Delta maintenance command compacts them into larger files?
OPTIMIZE compacts many small files into fewer larger ones, improving read performance. VACUUM (D) removes old unreferenced files, DESCRIBE HISTORY (B) shows the commit log, and REFRESH (A) reloads metadata.
Queries frequently filter a large Delta table by a high-cardinality column. Which technique co-locates related data to speed those filters?
Z-ORDER (or liquid clustering) co-locates related values so filters skip more files (data skipping). Dropping the column (D), aggressive VACUUM (C), and CSV conversion (B) don't improve filtered reads.
A scheduled job failed on its third task due to a transient error. What is a reasonable first step to recover without rerunning successful tasks?
Repairing a run reruns only the failed and dependent tasks, reusing successful results. Deleting the job (C), rewriting everything (A), and disabling UC (D) are not appropriate first steps.
Where can a data engineer see how long each task took and read the error/output logs for a job run?
The Jobs UI shows per-task durations, statuses, and logs for each run, which is where you diagnose failures. The Delta log (B) tracks table commits, and options C/D don't hold run logs.
The free Data Engineer Associate practice test mixes about 20 questions weighted like the exam. The full 300-question bank adds instant grading, flashcards and a timed mock exam.