- A
The volatile-lru policy evicts only keys with an expiry set, and there are many keys without expiry occupying memory
volatile-lru evicts only keys with TTL. If many non-volatile keys consume memory, volatile keys may be evicted even if overall memory appears free.
- B
The allkeys-lru policy would be more appropriate
Why wrong: allkeys-lru evicts any key, but that doesn't explain why volatile keys are being evicted with available memory.
- C
The maxmemory setting is not configured
Why wrong: If maxmemory is not set, Memorystore uses the instance memory size; eviction occurs when memory is full, not when free.
- D
The maxmemory-policy is misconfigured
Why wrong: The policy is correctly set to volatile-lru; the issue is memory allocation, not the policy itself.
Question 334 of 1,000
PCDOE Manage Database Solutions Practice Question
This PCDOE practice question tests your understanding of manage database solutions. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company uses Memorystore for Redis with the 'volatile-lru' eviction policy. They notice that recently added keys with TTL are being evicted even though there is still memory available. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"most likely"Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 volatile-lru policy evicts only keys with an expiry set, and there are many keys without expiry occupying memory
The 'volatile-lru' eviction policy in Memorystore for Redis evicts only keys that have a TTL (expiry) set, using an LRU (Least Recently Used) algorithm among those keys. If many keys without expiry are consuming memory, the eviction process will still target only the volatile keys, even if overall memory is not fully exhausted, because the policy is constrained to evict only from the subset of keys with TTLs. This explains why recently added keys with TTL are being evicted prematurely — the non-volatile keys are 'protected' from eviction, forcing the eviction of volatile keys to free memory.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
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 volatile-lru policy evicts only keys with an expiry set, and there are many keys without expiry occupying memory
Why this is correct
volatile-lru evicts only keys with TTL. If many non-volatile keys consume memory, volatile keys may be evicted even if overall memory appears free.
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
The allkeys-lru policy would be more appropriate
Why it's wrong here
allkeys-lru evicts any key, but that doesn't explain why volatile keys are being evicted with available memory.
- ✗
The maxmemory setting is not configured
Why it's wrong here
If maxmemory is not set, Memorystore uses the instance memory size; eviction occurs when memory is full, not when free.
- ✗
The maxmemory-policy is misconfigured
Why it's wrong here
The policy is correctly set to volatile-lru; the issue is memory allocation, not the policy itself.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Cisco often tests the misconception that 'volatile-lru' evicts all keys when memory is low, when in fact it only evicts keys with TTLs, leaving non-volatile keys untouched even if they are consuming the majority of memory.
Detailed technical explanation
How to think about this question
Under the hood, Redis maintains an LRU approximation for keys with TTLs when using 'volatile-lru', sampling a small pool of keys (default 5) and evicting the least recently used among them. This means that if the pool contains only recently added TTL keys, they may be evicted even if older volatile keys exist but are not sampled. In real-world scenarios, this often happens when a large number of non-volatile keys (e.g., session tokens without expiry) are stored alongside short-lived cache entries, causing the volatile keys to be evicted disproportionately.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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Manage Database Solutions — study guide chapter
Learn the concepts, then practise the questions
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FAQ
Questions learners often ask
What does this PCDOE question test?
Manage Database Solutions — This question tests Manage Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The volatile-lru policy evicts only keys with an expiry set, and there are many keys without expiry occupying memory — The 'volatile-lru' eviction policy in Memorystore for Redis evicts only keys that have a TTL (expiry) set, using an LRU (Least Recently Used) algorithm among those keys. If many keys without expiry are consuming memory, the eviction process will still target only the volatile keys, even if overall memory is not fully exhausted, because the policy is constrained to evict only from the subset of keys with TTLs. This explains why recently added keys with TTL are being evicted prematurely — the non-volatile keys are 'protected' from eviction, forcing the eviction of volatile keys to free memory.
What should I do if I get this PCDOE question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Last reviewed: Jul 4, 2026
This PCDOE practice question is part of Courseiva's free Google Cloud 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 PCDOE exam.
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