Exam Certified Data Engineer Professional topic 1 question 233 discussion

Actual exam question from Databricks's Certified Data Engineer Professional

Question #: 233
Topic #: 1

[All Certified Data Engineer Professional Questions]

A 'transactions' table has been liquid clustered on the columns 'product_id’, ’user_id' and 'event_date'.

Which operation lacks support for cluster on write?

A. CTAS and RTAS statements
B. spark.writeStream.format(’delta').mode(’append’)
C. spark.write.format('delta’).mode('append')
D. INSERT INTO operations

Show Suggested Answer

Suggested Answer: B 🗳️

by a68856c at Nov. 22, 2025, 6:06 p.m.

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_Lukas_

7 hours, 35 minutes ago

Selected Answer: B

Correct: B - Structured Streaming operations using spark.writeStream.format('delta').mode('append') do NOT support cluster on write by default. To enable clustering on write for streaming workloads, you must explicitly set the Spark configuration spark.databricks.delta.liquid.eagerClustering.streaming.enabled to true. Without this configuration flag, streaming writes bypass the automatic clustering optimization that other operations receive.

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Ral17

1 day, 2 hours ago

Selected Answer: B

This should be B. Only writeStream lacks support for liquid cluster

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a68856c

5 days ago

Selected Answer: B

https://docs.databricks.com/aws/en/delta/clustering#operations-that-support-clustering-on-write . By default writeStream does not support liquid cluster.

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