Second level caching is a query cache. The results of EF commands will be stored in the cache, so that the same EF
commands will retrieve their data from the cache rather than executing them against the database again.
How to upgrade to version 5
To support more advanced caching providers, this library uses different assemblies and NuGet packages now.
To upgrade to version 5, first remove the EFCoreSecondLevelCacheInterceptor dependency. It doesn't have any built-in
caching provider anymore.
But you can still use it to introduce your own custom caching provider by calling its
options.UseCustomCacheProvider<T>() method (and you won't need the new packages).
To install EFCoreSecondLevelCacheInterceptor as before, run the following command in the Package Manager Console:
This provider uses the StackExchange.Redis as a cache provider and it's preconfigured with a MessagePack serializer. To
use it, first you should install its new NuGet package:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
private readonly string _contentRootPath;
public Startup(IConfiguration configuration, IWebHostEnvironment env)
{
_contentRootPath = env.ContentRootPath;
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1)))
// Please use the `CacheManager.Core` or `EasyCaching.Redis` for the Redis cache provider.
);
var connectionString = Configuration["ConnectionStrings:ApplicationDbContextConnection"];
if (connectionString.Contains("%CONTENTROOTPATH%"))
{
connectionString = connectionString.Replace("%CONTENTROOTPATH%", _contentRootPath);
}
services.AddConfiguredMsSqlDbContext(connectionString);
services.AddControllersWithViews();
}
}
}
Using EasyCaching.Core as the cache provider
Here you can use the EasyCaching.Core, as a highly configurable cache
manager too.
To use its in-memory caching mechanism, add this entry to the .csproj file:
namespace EFSecondLevelCache.Core.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
const string providerName1 = "InMemory1";
services.AddEFSecondLevelCache(options =>
options.UseEasyCachingCoreProvider(providerName1, isHybridCache: false).ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
);
// Add an in-memory cache service provider
// More info: https://easycaching.readthedocs.io/en/latest/In-Memory/
services.AddEasyCaching(options =>
{
// use memory cache with your own configuration
options.UseInMemory(config =>
{
config.DBConfig = new InMemoryCachingOptions
{
// scan time, default value is 60s
ExpirationScanFrequency = 60,
// total count of cache items, default value is 10000
SizeLimit = 100,
// enable deep clone when reading object from cache or not, default value is true.
EnableReadDeepClone = false,
// enable deep clone when writing object to cache or not, default value is false.
EnableWriteDeepClone = false,
};
// the max random second will be added to cache's expiration, default value is 120
config.MaxRdSecond = 120;
// whether enable logging, default is false
config.EnableLogging = false;
// mutex key's alive time(ms), default is 5000
config.LockMs = 5000;
// when mutex key alive, it will sleep some time, default is 300
config.SleepMs = 300;
}, providerName1);
});
}
}
}
If you want to use the Redis as the preferred cache provider with EasyCaching.Core, first install the following
package:
Using EasyCaching.Core as a dynamic cache provider
If you want to support multitenancy in your application and have a different Redis database per each tenant, first
register multiple pre-configured providers with known providerNames and then select these providerNames based on the
current tenant this way dynamically:
services.AddEFSecondLevelCache(options =>
options.UseEasyCachingCoreProvider(
(serviceProvider, cacheKey) => "redis-db-" + serviceProvider.GetRequiredService<IHttpContextAccesor>().HttpContext.Request.Headers["tenant-id"],
isHybridCache: false)
// `Or` you can set the cache key prefix per tenant dynamically
.UseCacheKeyPrefix(serviceProvider => "EF_" + serviceProvider.GetRequiredService<IHttpContextAccesor>().HttpContext.Request.Headers["tenant-id"])
.ConfigureLogging(true)
.UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
);
Using CacheManager.Core as the cache provider [It's not actively maintained]
Also here you can use the CacheManager.Core, as a highly configurable cache
manager too.
To use its in-memory caching mechanism, add these entries to the .csproj file:
namespace EFSecondLevelCache.Core.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
options.UseCacheManagerCoreProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
);
// Add an in-memory cache service provider
services.AddSingleton(typeof(ICacheManager<>), typeof(BaseCacheManager<>));
services.AddSingleton(typeof(ICacheManagerConfiguration),
new CacheManager.Core.CacheConfigurationBuilder()
.WithJsonSerializer()
.WithMicrosoftMemoryCacheHandle(instanceName: "MemoryCache1")
.Build());
}
}
}
If you want to use the Redis as the preferred cache provider with CacheManager.Core, first install the
CacheManager.StackExchange.Redis package and then register its required services:
// Add Redis cache service provider
var jss = new JsonSerializerSettings
{
NullValueHandling = NullValueHandling.Ignore,
ReferenceLoopHandling = ReferenceLoopHandling.Ignore,
TypeNameHandling = TypeNameHandling.Auto,
Converters = { new SpecialTypesConverter() }
};
const string redisConfigurationKey = "redis";
services.AddSingleton(typeof(ICacheManagerConfiguration),
new CacheManager.Core.CacheConfigurationBuilder()
.WithJsonSerializer(serializationSettings: jss, deserializationSettings: jss)
.WithUpdateMode(CacheUpdateMode.Up)
.WithRedisConfiguration(redisConfigurationKey, config =>
{
config.WithAllowAdmin()
.WithDatabase(0)
.WithEndpoint("localhost", 6379)
// Enables keyspace notifications to react on eviction/expiration of items.
// Make sure that all servers are configured correctly and 'notify-keyspace-events' is at least set to 'Exe', otherwise CacheManager will not retrieve any events.
// You can try 'Egx' or 'eA' value for the `notify-keyspace-events` too.
// See https://redis.io/topics/notifications#configuration for configuration details.
.EnableKeyspaceEvents();
})
.WithMaxRetries(100)
.WithRetryTimeout(50)
.WithRedisCacheHandle(redisConfigurationKey)
.Build());
services.AddSingleton(typeof(ICacheManager<>), typeof(BaseCacheManager<>));
services.AddEFSecondLevelCache(options =>
options.UseCacheManagerCoreProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
);
Here is
the definition of the SpecialTypesConverter.
Using a custom cache provider
If you don't want to use the above cache providers, implement your custom IEFCacheServiceProvider and then introduce
it using the options.UseCustomCacheProvider<T>() method.
Note: Some database providers don't support special fields such as DateTimeOffset, TimeSpan, etc. For these
scenarios you will
need the related converters.
3- Setting up the cache invalidation:
This library doesn't need any settings for the cache invalidation. It watches for all of the CRUD operations using its
interceptor and then invalidates the related cache entries automatically.
But if you want to invalidate the whole cache manually, inject the IEFCacheServiceProvider service and then call its
_cacheServiceProvider.ClearAllCachedEntries() method or use it this way to specify the root cache keys which are a
collection of a Prefix+TableName:
// Partial cache invalidation using the specified table names
// This is useful when you are monitoring your DB's changes using the SqlTableDependency
_cacheServiceProvider.InvalidateCacheDependencies(new EFCacheKey(new HashSet<string>()
{
"EF_TableName1", // "EF_" is the cache key's prefix
"EF_TableName2"
}));
I you want to get notified about the cache-invalidation events and involved cache dependencies, use the
NotifyCacheInvalidation method:
NOTE: It doesn't matter where the Cacheable method is located in this expression
tree. It just adds
the standard TagWith method to mark this query as Cacheable. Later SecondLevelCacheInterceptor will use this tag
to identify the Cacheable queries.
Also it's possible to set the Cacheable() method's settings globally:
services.AddEFSecondLevelCache(options => options.UseMemoryCacheProvider(CacheExpirationMode.Absolute, TimeSpan.FromMinutes(5)).ConfigureLogging(true)
.UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
);
In this case the above query will become:
var post1 = context.Posts
.Where(x => x.Id > 0)
.OrderBy(x => x.Id)
.Cacheable()
.FirstOrDefault(); // Async methods are supported too.
If you specify the settings of the Cacheable() method explicitly such as
Cacheable(CacheExpirationMode.Sliding, TimeSpan.FromMinutes(5)), its setting will override the global setting.
Caching all of the queries
To cache all of the system's queries, just set the CacheAllQueries() method:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_");
options.CacheAllQueries(CacheExpirationMode.Absolute, TimeSpan.FromMinutes(30));
// Fallback on db if the caching provider fails.
options.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1));
});
// ...
This will put the whole system's queries in cache. In this case calling the Cacheable() methods won't be necessary. If
you specify the Cacheable() method, its setting will override this global setting. If you want to exclude some of the
queries from this global cache, apply the NotCacheable() method to them.
Caching some of the queries
To cache some of the system's queries based on their entity-types or table-names, use CacheQueriesContainingTypes or
CacheQueriesContainingTableNames methods:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
/*.CacheQueriesContainingTypes(
CacheExpirationMode.Absolute, TimeSpan.FromMinutes(30), TableTypeComparison.Contains,
typeof(Post), typeof(Product), typeof(User)
)*/
.CacheQueriesContainingTableNames(
CacheExpirationMode.Absolute, TimeSpan.FromMinutes(30), TableNameComparison.ContainsOnly,
"posts", "products", "users"
);
});
// ...
This will put the the specified system's queries in cache. In this case calling the Cacheable() methods won't be
necessary. If you specify the Cacheable() method, its setting will override this global setting. If you want to
exclude some of the queries from this global cache, apply the NotCacheable() method to them.
Also you can skip caching some of the defined DbContexts using SkipCachingDbContexts() method.
Skip caching of some of the queries
To skip caching some of the system's queries based on their SQL commands, set the SkipCachingCommands predicate:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
// How to skip caching specific commands
.SkipCachingCommands(commandText =>
commandText.Contains("NEWID()", StringComparison.InvariantCultureIgnoreCase));
});
// ...
Skip caching of some of the queries based on their results
To skip caching some of the system's queries based on their results, set the SkipCachingResults predicate:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
// Don't cache null values. Remove this optional setting if it's not necessary.
.SkipCachingResults(result =>
result.Value == null || (result.Value is EFTableRows rows && rows.RowsCount == 0));
});
// ...
Skip caching some of the queries based on their table names
To do not cache some of the system's queries based on their entity-types or table-names, use
CacheAllQueriesExceptContainingTypes or CacheAllQueriesExceptContainingTableNames methods:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
/*.CacheAllQueriesExceptContainingTypes(
CacheExpirationMode.Absolute, TimeSpan.FromMinutes(30),
typeof(Post), typeof(Product), typeof(User)
)*/
.CacheAllQueriesExceptContainingTableNames(
CacheExpirationMode.Absolute, TimeSpan.FromMinutes(30),
"posts", "products", "users"
);
});
// ...
This will not put the the specified system's queries in cache. In this case calling the Cacheable() methods won't be
necessary. If you specify the Cacheable() method, its setting will override this global setting.
Skip invalidating the related cache entries of a given query
Sometimes you don't want to invalidate the cache immediately, such when you are updating a post's likes or views count.
In this case to skip invalidating the related cache entries of a given CRUD command, set the
SkipCacheInvalidationCommands predicate:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
.SkipCacheInvalidationCommands(commandText =>
// How to skip invalidating the related cache entries of this query
commandText.Contains("NEWID()", StringComparison.InvariantCultureIgnoreCase));
});
// ...
Overriding the default cache-policy
Use OverrideCachePolicy() method to override the default/calculated cache-policy of the currently executing query:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
.OverrideCachePolicy(context =>
{
if (context.IsCrudCommand)
{
return null;
}
if (context.CommandTableNames.Contains(item: "posts"))
{
return new EFCachePolicy().ExpirationMode(CacheExpirationMode.NeverRemove);
}
return null; // Use the default/calculated EFCachePolicy
});
});
// ...
Using a different hash provider
This library uses
the XxHash64Unsafe
class to calculate the hash of a query and its parameters to produce a corresponding cache-key.
xxHash is an extremely fast non-cryptographic Hash algorithm. If you don't like it or you want to change it, just
implement the IEFHashProvider interface and then introduce it this way:
namespace EFCoreSecondLevelCacheInterceptor.AspNetCoreSample
{
public class Startup
{
public void ConfigureServices(IServiceCollection services)
{
services.AddEFSecondLevelCache(options =>
{
options.UseCustomHashProvider<MyCustomHashProvider>();
// ...
});
// ...
Disabling the interceptor for a while
If you want to disable this interceptor for a while, use the .EnableCachingInterceptor(enable: false) method. Its
default value is true.
Providing options to control the serialization behavior
The EFCacheKeyProvider class serializes parameter values of a DbCommand to JSON values. If it causes an exception in
some cases, you can specify a custom JsonSerializerOptions for it using the UseJsonSerializerOptions(options) method.
Does it work?!
You should enable the logging system to see the behind the scene of the caching interceptor.
First set the ConfigureLogging(true):
services.AddEFSecondLevelCache(options =>
options.UseMemoryCacheProvider().ConfigureLogging(true).UseCacheKeyPrefix("EF_")
// Fallback on db if the caching provider fails.
.UseDbCallsIfCachingProviderIsDown(TimeSpan.FromMinutes(1))
And then change the log level to Debug in your appsettings.json file:
Or ... you can use the second optional parameter of the ConfigureLogging method to access the published events of this
library more easily:
.ConfigureLogging(enable: environment.IsDevelopment(), cacheableEvent: args =>
{
switch (args.EventId)
{
case CacheableLogEventId.CacheHit:
break;
case CacheableLogEventId.QueryResultCached:
break;
case CacheableLogEventId.QueryResultInvalidated:
args.ServiceProvider.GetRequiredService<ILoggerFactory>()
.CreateLogger(nameof(EFCoreSecondLevelCacheInterceptor))
.LogWarning(message: "{EventId} -> {Message} -> {CommandText}", args.EventId,
args.Message, args.CommandText);
break;
case CacheableLogEventId.CachingSkipped:
break;
case CacheableLogEventId.InvalidationSkipped:
break;
case CacheableLogEventId.CachingSystemStarted:
break;
case CacheableLogEventId.CachingError:
break;
case CacheableLogEventId.QueryResultSuppressed:
break;
case CacheableLogEventId.CacheDependenciesCalculated:
break;
case CacheableLogEventId.CachePolicyCalculated:
break;
}
})
Now after running a query multiple times, you should have these logged lines:
Suppressed result with a TableRows[ee20d2d7-ffc7-4ff9-9484-e8d4eecde53e] from the cache[KeyHash: EB153BD4, CacheDependencies: Page.].
Using the TableRows[ee20d2d7-ffc7-4ff9-9484-e8d4eecde53e] from the cache.
Notes:
Having the Suppressed the result with the TableRows message means the caching interceptor is working fine.
The next Executed DbCommand means nothing and it always will be logged by EF.
At the beginning there will be a lot of internal commands executed by the EF to run migrations, etc. Ignore these
commands, because you will see the Suppressed the result with the TableRows messages for the frequently running
queries.
Also you should verify it with a real DB profiler. It will log the 1st executed query and then on the 2nd run, you
won't see it anymore.
Good candidates for query caching are global site settings and public data, such as infrequently changing articles or
comments. It can also be beneficial to cache data specific to a user so long as the cache expires frequently enough
relative to the size of the user base that memory consumption remains acceptable. Small, per-user data that frequently
exceeds the cache's lifetime, such as a user's photo path, is better held in user claims, which are stored in cookies,
than in this cache.
Scope
This cache is scoped to the application, not the current user. It does not use session variables. Accordingly, when
retrieving cached per-user data, be sure queries in include code such as .Where(x => .... && x.UserId == id).
Invalidation
This cache is updated when an entity is changed (insert, update, or delete) via a DbContext that uses this library. If
the database is updated through some other means, such as a stored procedure or trigger, the cache becomes stale.
Transactions
To avoid complications, all of the queries inside an explicit transaction (context.Database.BeginTransaction()) will
not be cached. But the cache invalidations due to its CRUD operations will occur. You can use
.AllowCachingWithExplicitTransactions(true) setting to disable it.
