SK0-005 server-administration Practice Question
A MySQL database server on Linux is experiencing high CPU utilization during peak business hours. Upon investigation, the administrator finds that the query cache hit ratio is below 20%, and the query_cache_size is set to 0. The server has 64 GB of RAM and the database workload is primarily read-heavy. Which of the following actions should the administrator take FIRST to improve performance?
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
✓
Set query_cache_size to an appropriate value, such as 256M, and monitor.
Option D is correct because the query cache is disabled (size 0). Enabling it and setting an appropriate size will increase cache hits and reduce CPU load. Option A adds RAM but does not address the misconfigured cache. Option B identifies queries but does not directly fix the cache. Option C rebuilds indexes, which may not impact query caching.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Set query_cache_size to an appropriate value, such as 256M, and monitor.
Why this is correct
Enabling and sizing the query cache for a read-heavy workload can dramatically increase cache hits and reduce CPU.
- ✗
Add more RAM to the server.
Why it's wrong here
More RAM could help overall, but the immediate bottleneck is that the query cache is turned off, not insufficient memory.
- ✗
Rebuild all indexes on the database tables.
Why it's wrong here
Index maintenance may improve some queries but does not enable the query cache, which is the immediate issue.
- ✗
Enable the slow query log to identify inefficient queries.
Why it's wrong here
This is a diagnostic step, not a performance fix; the low cache hit ratio directly points to query_cache_size.
Go deeper
Related to this question
Learn chapter
Disaster Recovery and Business Continuity Planning
Key term
SQL
SQL is a standardized programming language used to manage and manipulate relational databases, enabling querying, updating, and data retrieval.
Key term
Impact
Impact is the measure of the potential damage or harm that a risk event could cause to an organization's assets, operations, or reputation.
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Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed July 2026 · checked against the official CompTIA exam blueprint
This SK0-005 practice question is part of Courseiva's free CompTIA 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 SK0-005 exam.