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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
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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.
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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.
} |