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MLS-C01 Data Engineering Practice Question

Exhibit

Refer to the exhibit.

Resources:
  MyGlueJob:
    Type: AWS::Glue::Job
    Properties:
      Command:
        Name: glueetl
        ScriptLocation: s3://my-bucket/scripts/etl.py
      DefaultArguments:
        --TempDir: s3://my-bucket/temp/
        --job-bookmark-option: job-bookmark-enable
      MaxRetries: 0
      MaxConcurrentRuns: 3
      Role: arn:aws:iam::123456789012:role/GlueServiceRole

A company uses AWS Glue jobs with job bookmarks enabled to process incremental data. They notice that the job processes all data each time instead of only new data. What is the most likely reason?

⚠ Common exam trap

The trap here is that candidates often overlook the impact of concurrent runs on bookmark state, assuming that parallelism only affects performance, not data integrity, and instead focus on superficial configuration issues like TempDir or bookmark key columns.

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

✓

The MaxConcurrentRuns is set to 3, which can cause bookmark conflicts.

Setting MaxConcurrentRuns to a value greater than 1 can cause job bookmark conflicts. When multiple concurrent runs of the same AWS Glue job attempt to update the bookmark state simultaneously, they can overwrite each other's progress, leading to inconsistent bookmark tracking. This results in the job reprocessing all data instead of only incremental data, as the bookmark fails to correctly record the last processed position.

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

  • ✗

    The TempDir is not configured correctly.

    Why it's wrong here

    TempDir is for temporary files, not bookmarks.

  • ✗

    The job bookmark option is set to 'job-bookmark-enable' but should be 'job-bookmark-disable'.

    Why it's wrong here

    Enabling is correct for incremental processing.

  • ✗

    The source data does not have a column that can be used as a bookmark key.

    Why it's wrong here

    While true, the more direct cause is concurrent runs.

  • ✓

    The MaxConcurrentRuns is set to 3, which can cause bookmark conflicts.

    Why this is correct

    Multiple concurrent runs can corrupt bookmark state.

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JA

Written by Johnson Ajibi, MSc IT Security

Senior Network & Security Engineer · founder of Courseiva

This MLS-C01 practice question is part of Courseiva's free Amazon Web Services 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 MLS-C01 exam.