MeasureUp Test Performance Analysis 3

Question 1

Which queueing theory metric describes the average number of requests waiting in a queue at any given moment?

Accepted Answer

Mean queue length

Answer

Mean queue length (Lq) from Little's Law counts the average backlog of waiting requests.

Question 2

A database query plan shows a 'Sequential Scan' on a large table. What is the most likely performance fix?

Accepted Answer

Add an index on the queried column

Answer

Sequential scans on large tables are slow; adding an appropriate index allows the planner to use an index scan instead.

Question 3

What is 'coordinated omission' in load testing?

Accepted Answer

Load generators skipping requests when the system is slow, masking latency

Answer

Coordinated omission occurs when a load tool waits for a response before scheduling the next request, hiding the true latency distribution under load.

Question 4

Which metric should you monitor to detect memory pressure before an out-of-memory event occurs?

Accepted Answer

Page fault rate

Answer

A rising page fault rate indicates the OS is swapping memory pages, signaling that RAM is insufficient for the workload.

Question 5

In APM (Application Performance Monitoring), what is a 'trace' composed of?

Accepted Answer

A collection of spans representing operations in a single request

Answer

A distributed trace is built from spans, each representing a timed unit of work across services handling one request.

MeasureUp Practice Test

MeasureUp Practice Test

MeasureUp Test Performance Analysis 3