Cache In-memory In ASP.Internet Core > 자유게시판

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Caching can significantly improve the performance and scalability of an app by reducing the work required to generate content. Caching works finest with data that modifications infrequently and is costly to generate. Caching makes a duplicate of data that can be returned a lot quicker than from the supply. Apps must be written and examined to by no means depend upon cached information. The simplest cache relies on the IMemoryCache. IMemoryCache represents a cache saved in the memory of the online server. Apps operating on a server farm (a number of servers) ought to ensure periods are sticky when utilizing the in-Memory Wave Program cache. Sticky sessions be sure that requests from a client all go to the identical server. For example, Azure Net apps use Software Request Routing (ARR) to route all requests to the same server. Non-sticky sessions in an internet farm require a distributed cache to keep away from cache consistency issues. For some apps, a distributed cache can help larger scale-out than an in-memory cache.

Using a distributed cache offloads the cache memory to an external process. The in-memory cache can store any object. The in-memory and distributed cache retailer cache gadgets as key-worth pairs. Web Commonplace 2.0 or later. Any .Internet implementation that targets .Net Commonplace 2.Zero or later. Internet Framework 4.5 or later. Code ought to at all times have a fallback option to fetch information and never rely on a cached worth being obtainable. The cache makes use of a scarce useful resource, memory. Restrict cache development: - Don't insert exterior enter into the cache. For example, using arbitrary consumer-provided enter as a cache key just isn't advisable because the input may eat an unpredictable amount of memory. Use expirations to restrict cache progress. Use SetSize, Dimension, and SizeLimit to limit cache measurement. It's up to the developer to limit cache measurement. Using a shared memory cache from Dependency Injection and calling SetSize, Dimension, or SizeLimit to restrict cache dimension can cause the app to fail.

When a size restrict is ready on a cache, Memory Wave Program all entries must specify a measurement when being added. This may result in issues since builders may not have full management on what makes use of the shared cache. When using SetSize, Size, or SizeLimit to limit cache, create a cache singleton for caching. For extra information and an instance, see Use SetSize, Dimension, and SizeLimit to restrict cache dimension. A shared cache is one shared by different frameworks or libraries. In-memory caching is a service that is referenced from an app utilizing Dependency Injection. The following code uses TryGetValue to test if a time is in the cache. Within the previous code, the cache entry is configured with a sliding expiration of three seconds. If the cache entry is not accessed for more than three seconds, it gets evicted from the cache. Every time the cache entry is accessed, it stays in the cache for an extra 3 seconds.

The CacheKeys class is a part of the download sample. In the previous code, the cache entry is configured with a relative expiration of in the future. The cache entry will get evicted from the cache after someday, even when it is accessed within this timeout period. The next code uses GetOrCreate and GetOrCreateAsync to cache data. A cached merchandise set with only a sliding expiration is vulnerable to by no means expiring. If the cached merchandise is repeatedly accessed inside the sliding expiration interval, the item never expires. Combine a sliding expiration with an absolute expiration to ensure the item expires. The absolute expiration units an higher bound on how lengthy the item might be cached whereas still permitting the merchandise to expire earlier if it isn't requested within the sliding expiration interval. If both the sliding expiration interval or the absolute expiration time go, the item is evicted from the cache. The preceding code ensures the data won't be cached longer than the absolute time.

GetOrCreate, GetOrCreateAsync, and Get are extension strategies in the CacheExtensions class. These strategies extend the aptitude of IMemoryCache. Units the cache precedence to CacheItemPriority.NeverRemove. Units a PostEvictionDelegate that gets called after the entry is evicted from the cache. The callback is run on a unique thread from the code that removes the item from the cache. A MemoryCache instance might optionally specify and implement a size limit. The cache size restrict would not have a defined unit of measure as a result of the cache has no mechanism to measure the dimensions of entries. If the cache size limit is ready, all entries must specify dimension. It is as much as the developer to limit cache size. The size specified is in models the developer chooses. If the web app was primarily caching strings, each cache entry measurement could possibly be the string size. The app might specify the size of all entries as 1, and the scale restrict is the rely of entries. If SizeLimit is not set, the cache grows with out sure.