DBS-C01 Management and Operations Practice Question
Exhibit
Given the following CloudWatch Logs Insights query for an Amazon Aurora MySQL database: fields @timestamp, @message | filter @message like /(?i)(error|fatal|exception)/ | sort @timestamp desc | limit 20
Refer to the exhibit. A database engineer runs the query above to troubleshoot an application error. The query returns no results even though the database is generating errors. What is the most likely reason?
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 log stream format uses a different field name for the error message
The query filters on the 'message' field, but the log stream format may use a different field name for the error message, such as 'errorMessage' or 'event.message'. Since the query returns no results despite errors existing, the most likely reason is a field name mismatch. Option B is incorrect because the query uses a regex pattern with case-insensitive matching (indicated by the 'i' flag), so case sensitivity is not an issue. Option C is incorrect because queries in CloudWatch Logs Insights default to the last 15 minutes if no time range is specified, so that would not cause zero results if errors are recent. Option D is incorrect because exporting to CloudWatch Logs is not required for querying; the logs are already in CloudWatch Logs.
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 log stream format uses a different field name for the error message
Why this is correct
Correct. The log stream format might use a different field name for the error message, such as 'errorMessage' or 'event.message'. The query expects the field 'message', but the actual log stream may store the error in another field, causing the query to return no results.
- ✗
The regex pattern does not match because it is case-sensitive
Why it's wrong here
Incorrect. The regex pattern uses the 'i' flag for case-insensitive matching, so case sensitivity is not the issue.
- ✗
The query does not specify a time range, so no results are returned
Why it's wrong here
Incorrect. If no time range is specified, CloudWatch Logs Insights defaults to the last 15 minutes. If errors occurred within that time, results would be returned. The absence of results points to a field name mismatch, not a missing time range.
- ✗
The log group has not been configured to export to CloudWatch Logs
Why it's wrong here
Incorrect. Exporting to CloudWatch Logs is not a prerequisite for querying logs. The logs are already in CloudWatch Logs and can be queried directly regardless of export configuration.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DBS-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 DBS-C01 exam.