Tutorials Design Patterns in C#
Distributed Cache Pattern — Complete Guide
Distributed Cache Pattern — Complete Guide: free step-by-step lesson with examples, common mistakes, and interview tips — part of Design Patterns in C# on Toolliyo Academy.
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Design Patterns in C# · Lesson 54 of 69
Distributed Cache Pattern
GoF Core ✓ → Enterprise ✓ → Cloud & Craft
Cloud & Craft · 3 — Microservices & interviews · ~10 min · Module 6: Microservices & Cloud Patterns
What is this?
Distributed cache stores hot data in a shared Redis/Memcached cluster so all app nodes see the same cache.
Why should you care?
ShopNest API replicas must not each miss and stampede SQL for the same PDP.
See it live — copy this example
Paste into a C# console or class library project and run dotnet run.
public interface ICache
{
Task<string?> GetAsync(string key);
Task SetAsync(string key, string value, TimeSpan ttl);
}
// Get product:42 -> on miss load SQL -> Set with TTL
Console.WriteLine("GET product:HD-100");
Console.WriteLine("MISS -> SQL -> SET EX 60");Run Example »
Edit the code below and click Run to see the result in Toolliyo’s live editor.
What happened?
- Cache-aside is common.
- TTL bounds staleness.
- Invalidate on stock/price events.
- Stampede control matters at scale.
Practice next
- Cache ShopNest PDP JSON 60s.
- Delete key on price change.
- Measure hit ratio.
- Namespace keys by env.
- Negative cache short TTL for missing SKUs.
Remember
Shared hot data. TTL + invalidation. Protect the DB.
ShopNest Redis PDP cache
All API pods share product cache.
Outcome: SQL QPS drops in sales.
Interview prep for this lesson
Practice these questions aloud after reading—each links to a full structured answer.
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