Issue with In-memory Caching in ASP.NET Core 6 Causing Stale Data Retrieval
I'm experiencing an issue with in-memory caching in my ASP.NET Core 6 application where retrieving cached data occasionally returns stale values. I'm using the built-in IMemoryCache interface but have noticed that when I update the underlying data source, the cached values do not reflect these changes immediately. I have implemented caching like this: ```csharp public class DataService { private readonly IMemoryCache _cache; private const string CacheKey = "DataKey"; public DataService(IMemoryCache cache) { _cache = cache; } public List<MyData> GetData() { if (!_cache.TryGetValue(CacheKey, out List<MyData> cachedData)) { // Simulate data fetch from a database cachedData = FetchDataFromDatabase(); var cacheEntryOptions = new MemoryCacheEntryOptions() .SetSlidingExpiration(TimeSpan.FromMinutes(5)); _cache.Set(CacheKey, cachedData, cacheEntryOptions); } return cachedData; } public void UpdateData(MyData updatedData) { // Update the data in the database UpdateDataInDatabase(updatedData); // Here, I am not clearing the cache, expecting it to update on the next fetch } } ``` The problem arises when I update the data using the `UpdateData` method and then immediately call `GetData`. I still get the old values from the cache instead of the updated ones. I expected that since I set a sliding expiration, it would refresh on my next call after the update. I also tried to manually remove the cache entry in the `UpdateData` method using `_cache.Remove(CacheKey);`, which does clear the cache but leads to unnecessary database hits. Is there a best practice for handling updates efficiently with IMemoryCache in ASP.NET Core without compromising performance? Additionally, I am seeing a slight performance hit whenever the cache is missed, and I'm wondering if there is a better way to manage this lifecycle. Any suggestions or examples would be greatly appreciated!