MCSD MCSD Performance Optimization and Scalability 3

Question 1

What is the N+1 query problem in Entity Framework Core and how is it typically resolved?

Accepted Answer

Loading a collection triggers one query per item; resolved by using .Include() for eager loading

Answer

The N+1 problem occurs when lazy loading fires a separate SQL query for each related entity in a collection; .Include() generates a JOIN to fetch everything in one query.

Question 2

In Azure, what does Application Insights help developers do from a performance perspective?

Accepted Answer

Monitor response times, failure rates, and dependencies to identify performance bottlenecks in live applications

Answer

Application Insights collects telemetry including request durations, dependency call times, exceptions, and custom metrics, enabling performance diagnosis in production.

Question 3

What is the purpose of output caching introduced in ASP.NET Core 7 compared to the older Response Caching middleware?

Accepted Answer

Output caching stores responses on the server and supports programmatic invalidation and tagging for finer cache control

Answer

ASP.NET Core 7 Output Caching stores responses server-side with support for cache tags, custom policies, and programmatic eviction, giving developers more control than the HTTP-header-based response caching middleware.

Question 4

Which .NET garbage collection mode is recommended for server-side ASP.NET Core applications to maximize throughput?

Accepted Answer

Server GC mode, which runs concurrent GC on all available CPU cores

Answer

Server GC uses one GC heap per logical CPU core and runs collection concurrently across all cores, dramatically increasing throughput for multi-core server workloads.

Question 5

What does the Span<T> type in .NET provide that makes it useful for performance-critical code?

Accepted Answer

A stack-allocated view over contiguous memory that avoids heap allocations and GC overhead

Answer

Span<T> is a ref struct that represents a contiguous region of arbitrary memory (stack, heap, or unmanaged) without copying data, enabling zero-allocation slicing and parsing operations.

MCSD - Microsoft Certified Solutions Developer Practice Test

MCSD - Microsoft Certified Solutions Developer Practice Test

MCSD MCSD Performance Optimization and Scalability 3