Databricks-Spark-Assoc Structured Streaming Practice Question
You are writing a Structured Streaming query that reads from a Kafka topic and outputs to the console. You want to see only the newly arrived data in each micro-batch, without aggregations. Which output mode should you use?
⚠ Common exam trap
A common mix-up: candidates confuse Update mode with Append mode, especially when no aggregations are involved, leading to unnecessary complexity.
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
✓
Append
In Structured Streaming, Append mode is the default and outputs only new rows added since the last trigger. For a stateless query like reading from Kafka and writing to console, each micro-batch contains only new data. Update and Complete modes are designed for aggregations, where they output updated or full results, respectively.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Update with watermark
Why it's wrong here
Update mode with a watermark still outputs only updated rows, but without aggregations there are no updates. Adding a watermark does not change the fundamental behavior; it only affects stateful operations. This mode is not suitable for simply showing new data. Thus, it is incorrect.
- ✗
Update
Why it's wrong here
Update mode outputs only rows that have been updated since the last trigger. Without aggregations, there are no updates to existing rows; each row is new. Thus, Update mode would behave similarly to Append but is not the intended mode for this scenario. It is typically used with aggregations to output updated results.
- ✓
Append
Why this is correct
Append mode outputs only new rows that have been added since the last trigger. Since there are no aggregations, each micro-batch contains only the new data from Kafka. This matches the requirement to see only newly arrived data. Therefore, Append mode is correct.
- ✗
Complete
Why it's wrong here
Complete mode outputs the entire result table after each trigger. Without aggregations, this would mean outputting all data received so far, not just new data. This does not meet the requirement to see only newly arrived data. Complete mode is used with aggregations to output the full result set.
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 Databricks exam blueprint
This Databricks-Spark-Assoc practice question is part of Courseiva's free Databricks 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 Databricks-Spark-Assoc exam.