This DP-300 practice question tests your understanding of monitor, configure, and optimize database resources. 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.
Refer to the exhibit. An Azure SQL Database is experiencing performance degradation. Based on the Extended Events and wait statistics, which is the most likely root 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 the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
I/O subsystem bottleneck
The exhibit shows PAGEIOLATCH_SH and WRITELOG waits dominating the wait statistics, which are classic indicators of I/O subsystem bottlenecks. PAGEIOLATCH_SH waits occur when a session is waiting for a data page to be read from disk into the buffer pool, while WRITELOG waits indicate delays in writing to the transaction log. These waits are not caused by CPU or memory pressure, but by slow disk I/O, making option C the correct root cause.
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.
✗
Blocking due to lock contention
Why it's wrong here
LCK_M_S waits are minimal compared to PAGEIOLATCH_SH.
✗
CPU pressure from high-complexity queries
Why it's wrong here
CPU time is moderate; wait stats point to I/O.
✓
I/O subsystem bottleneck
Why this is correct
PAGEIOLATCH_SH waits indicate I/O latency.
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.
✗
Insufficient memory allocation for the database
Why it's wrong here
Memory pressure typically shows PAGEIOLATCH_SH, but the primary indicator is high logical reads and IO waits.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates see PAGEIOLATCH_SH and assume it is always caused by insufficient memory, but the combination with WRITELOG waits clearly points to an I/O bottleneck, not a memory issue.
Trap categories for this question
Command / output trap
Memory pressure typically shows PAGEIOLATCH_SH, but the primary indicator is high logical reads and IO waits.
Detailed technical explanation
How to think about this question
PAGEIOLATCH_SH is a latch wait that occurs when a thread must wait for a data page to be read from disk into the buffer pool; high values indicate the storage subsystem cannot keep up with read requests. WRITELOG waits specifically measure time spent waiting for the transaction log to be flushed to disk, which is critical for write-heavy workloads and is often caused by slow log disk throughput or high log generation rates. In Azure SQL Database, these waits can also be exacerbated by the service tier's IOPS or throughput limits, such as DTU or vCore-based resource governance.
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.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this DP-300 question in full detail.
Monitor, configure, and optimize database resources — This question tests Monitor, configure, and optimize database resources — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: I/O subsystem bottleneck — The exhibit shows PAGEIOLATCH_SH and WRITELOG waits dominating the wait statistics, which are classic indicators of I/O subsystem bottlenecks. PAGEIOLATCH_SH waits occur when a session is waiting for a data page to be read from disk into the buffer pool, while WRITELOG waits indicate delays in writing to the transaction log. These waits are not caused by CPU or memory pressure, but by slow disk I/O, making option C the correct root cause.
What should I do if I get this DP-300 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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Question Discussion
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