Caching in C# (.NET): Redis, MemoryCache and Other Solutions

Caching in C# (.NET): Redis, MemoryCache and Alternatives

Caching is one of the key tools for improving the performance of C# (.NET) applications. It helps reduce response time, lower database load, and decrease infrastructure costs. In this article, we will cover built-in .NET mechanisms, popular implementations based on Redis, as well as alternative solutions such as NCache and Couchbase.

1. Built-in Caching: MemoryCache

MemoryCache (namespace Microsoft.Extensions.Caching.Memory) is a simple and fast cache that stores data in the RAM of a single process. It is ideal for single-threaded applications or web servers with a single instance.

Installation and Setup

dotnet add package Microsoft.Extensions.Caching.Memory

Basic Usage Example

using Microsoft.Extensions.Caching.Memory;

public class DataService{    private readonly IMemoryCache _cache;    private readonly TimeSpan _cacheDuration = TimeSpan.FromMinutes(5);

    public DataService(IMemoryCache cache) => _cache = cache;

    public async Task<string> GetDataAsync(string key)    {        if (!_cache.TryGetValue(key, out string cachedData))        {            cachedData = await FetchFromDatabaseAsync(key);            _cache.Set(key, cachedData, new MemoryCacheEntryOptions            {                AbsoluteExpirationRelativeToNow = _cacheDuration            });        }        return cachedData;    }}

Advantages and Disadvantages

• + Simplicity, zero network latency.
• + Built-in expiration support (absolute/sliding).
• - Does not work when scaling across multiple servers.
• - Cache is cleared upon application restart.

2. Distributed Caching: Redis

Redis is the most popular choice for distributed caching in the .NET ecosystem. It runs as a separate service accessible to all application instances. In .NET, the IDistributedCache abstraction is used.

Package Installation

dotnet add package Microsoft.Extensions.Caching.StackExchangeRedis

Configuration in Program.cs

builder.Services.AddStackExchangeRedisCache(options =>{    options.Configuration = "localhost:6379";    options.InstanceName = "MyAppCache";});

Example of Working with IDistributedCache

public class RedisCacheService{    private readonly IDistributedCache _cache;

    public RedisCacheService(IDistributedCache cache) => _cache = cache;

    public async Task SetAsync(string key, byte[] data, int minutes = 10)    {        await _cache.SetAsync(key, data, new DistributedCacheEntryOptions        {            AbsoluteExpirationRelativeToNow = TimeSpan.FromMinutes(minutes)        });    }

    public async Task<byte[]> GetAsync(string key)    {        return await _cache.GetAsync(key);    }}

Advanced Redis Features

• Object Serialization: use System.Text.Json or Newtonsoft.Json.
• Tag-based Invalidation: third-party libraries (e.g., EasyCaching.Redis) allow grouping entries.
• Pub/Sub: for cache change notifications.

3. Alternatives to Redis

3.1 NCache

NCache is a commercial solution (with a free version) supporting .NET. It provides advanced features: synchronization between nodes, SQL-like queries to the cache, ASP.NET session caching.

• + Built-in support for IDist