Day 21 – Performance Tuning for .NET Applications (Caching, Async, Profiling)

Format: Tutorial + architecture diagrams + code examples + best practices


Introduction

Performance tuning is critical for scalable and responsive FullStack applications. FullStack .NET developers need to optimize backend APIs, database queries, and frontend interactions to deliver fast, reliable user experiences.

At CuriosityTech.in, learners master caching strategies, asynchronous programming, and profiling techniques to ensure high-performing .NET applications.


1. Common Performance Bottlenecks

AreaBottleneckImpact
DatabaseInefficient queries, missing indexesSlow response times
BackendBlocking calls, synchronous operationsThread starvation, delayed responses
FrontendLarge payloads, unoptimized assetsSlow page load, poor UX
LoggingExcessive synchronous loggingHigh I/O overhead

2. Caching Strategies in .NET

Types of Caching:

TypeDescriptionExample
In-MemoryStore frequently used data in server memoryIMemoryCache
DistributedShare cache across multiple serversRedis, Memcached
Response CachingCache HTTP responses[ResponseCache(Duration = 60)]

In-Memory Cache Example:

public class JobService : IJobService

{

    private readonly IMemoryCache _cache;

    private readonly ApplicationDbContext _db;

    public JobService(IMemoryCache cache, ApplicationDbContext db)

    {

        _cache = cache;

        _db = db;

    }

    public List<Job> GetAllJobs()

    {

        return _cache.GetOrCreate(“jobs”, entry =>

        {

            entry.AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(10);

            return _db.Jobs.ToList();

        });

    }

}

Benefits:

  • Reduces database load

  • Improves API response times

  • Simple to implement for read-heavy applications


3. Asynchronous Programming

Async/Await in .NET

public async Task<List<Job>> GetJobsAsync()

{

    return await _db.Jobs.ToListAsync();

}

Advantages:

  • Non-blocking I/O

  • Efficient thread usage

  • Improves scalability under high load

Async Best Practices:

  • Avoid async void except for event handlers

  • Use ConfigureAwait(false) in library code

  • Keep methods fully asynchronous to avoid blocking threads


4. Profiling and Monitoring

Tools:

ToolPurpose
dotTrace / JetBrains Rider ProfilerCPU and memory profiling
Visual Studio ProfilerIdentify slow methods and bottlenecks
Application InsightsMonitor performance in Azure
MiniProfilerLightweight profiling for web requests

Sample Profiling Workflow:

  1. Run profiler during load testing

  2. Identify slow queries and heavy operations

  3. Apply caching, async methods, or query optimization

  4. Re-test and measure improvement


5. Real-World Project: CuriosityTech Course Portal Performance Optimization

  • Scenario: Optimize Course Portal API for high traffic

  • Applied Techniques:

    • Cached frequently accessed course lists (IMemoryCache)

    • Converted blocking database calls to async EF Core queries

    • Profiled endpoints using Application Insights to detect slow queries

  • Outcome:

    • Reduced average API response time by 40%

    • Improved user experience on frontend

    • Reduced server load and resource consumption

Performance Flow Diagram:

[Frontend Request] –> [API Controller (Async)] –> [Service Layer (Cached)] –> [Database]

       |

       V

[Profiling & Monitoring for Bottleneck Detection]


6. Best Practices

  • Implement caching wisely to avoid stale data

  • Prefer async programming for I/O-bound operations

  • Optimize EF Core queries using Include, AsNoTracking, and Select

  • Profile applications regularly to detect memory leaks or CPU bottlenecks

  • Monitor production performance using Azure Application Insights or AWS CloudWatch


7. CuriosityTech.in Mentorship Insights


Conclusion

Performance tuning is a critical skill for FullStack .NET developers. By applying caching, async programming, and profiling techniques, developers can deliver high-performance, scalable applications. At CuriosityTech.in, learners practice these optimizations in real-world projects, ensuring they are ready for industry-standard FullStack development.

The next step is Day 22 – Unit Testing and Test-Driven Development (TDD) in .NET, focusing on writing robust, maintainable code with automated testing.

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