Cache-Aside Pattern

Details in Cache-Aside pattern - Azure Architecture Center | Microsoft Learn

Problem

Repeated access to info held in a data store.
Cached data to be consistent with data in the data store.

Solution

Caching systems provide read-through and write-through/write-behind operations.

Determine whether the item is currently held in the cache.
If the item is not currently in the cache, read the item from the data store.
Store a copy of the item in the cache.

Caching in practice

private static ConnectionMultiplexer Connection;

// Redis connection string information
private static Lazy<ConnectionMultiplexer> lazyConnection = new Lazy<ConnectionMultiplexer>(() =>
{
    string cacheConnection = ConfigurationManager.AppSettings["CacheConnection"].ToString();
    return ConnectionMultiplexer.Connect(cacheConnection);
});

public static ConnectionMultiplexer Connection => lazyConnection.Value;

If we need to invalidate an object in the cache when the value is changed by the app. → We need to update the original data and then remove the cached item from the cache.

public async Task UpdateEntityAsync(MyEntity entity)
{
    // Update the object in the original data store.
    await this.store.UpdateEntityAsync(entity).ConfigureAwait(false);

    // Invalidate the current cache object.
    var cache = Connection.GetDatabase();
    var id = entity.Id;
    var key = $"MyEntity:{id}"; // The key for the cached object.
    await cache.KeyDeleteAsync(key).ConfigureAwait(false); // Delete this key from the cache.
}

Design Patterns & Architecture

Cache-Aside Pattern

Analytics

Related content