L1L2RedisCache is an implementation of IDistributedCache with a strong focus on performance. It leverages IMemoryCache as a level 1 cache and RedisCache as a level 2 cache, with level 1 evictions being managed via Redis pub/sub.
L1L2RedisCache is heavily inspired by development insights provided over the past several years by StackOverflow. It attempts to simplify those concepts into a highly accessible IDistributedCache implementation that is more performant.
I expect to gracefully decomission this project when StackExchange.Redis has client-side caching support.
It is intended that L1L12RedisCache be used as an IDistributedCache implementation.
L1L2RedisCache can be registered during startup with the following IServiceCollection extension method:
services.AddL1L2RedisCache(options =>
{
options.Configuration = "localhost";
options.InstanceName = "Namespace:Prefix:";
});
L1L2RedisCache options are an extension of the standard RedisCache RedisCacheOptions. The following additional customizations are supported:
The type of messaging system to use for L1 memory cache eviction.
| MessagingType | Description | Suggestion |
|---|---|---|
Default |
Use standard L1L2RedisCache pub/sub messages for L1 memory cache eviction. |
Default behavior. The Redis server requires no additional configuration. |
KeyeventNotifications |
Use keyevent notifications for L1 memory eviction instead of standard L1L2RedisCache pub/sub messages. The Redis server must have keyevent notifications enabled. |
This is only advisable if the Redis server is already using keyevent notifications with at least a ghE configuration and the majority of keys in the server are managed by L1L2RedisCache. |
KeyspaceNotifications |
Use keyspace notifications for L1 memory eviction instead of standard L1L2RedisCache pub/sub messages. The Redis server must have keyspace notifications enabled. |
This is only advisable if the Redis server is already using keyevent notifications with at least a ghK configuration and the majority of keys in the server are managed by L1L2RedisCache. |
L1L2RedisCache will generally outperform RedisCache, especially in cases of high volume or large cache entries. As entries are opportunistically pulled from memory instead of Redis, costs of latency, network, and Redis operations are avoided. Respective performance gains will rely heavily on the impact of afforementioned factors.
Due to the complex nature of a distributed L1 memory cache, cache entries with sliding expirations are only stored in L2 (Redis). These entries will show no performance improvement over the standard RedisCache, but incur no performance penalty.